فهرست مطالب

  • سال پانزدهم شماره 1 (پیاپی 55، فروردین و اردیبهشت 1398)
  • تاریخ انتشار: 1398/02/01
  • تعداد عناوین: 18
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  • شکیبا کیانیانی، محمد جواد وریدی *، مهدی وریدی صفحات 1-11
    چربی منبعی از انرژی مورد نیاز بدن و ویتامین های محلول در آن بوده و برکیفیت و ویژگی های تکنولوژیک محصول نهایی مانند بافت و عطر و طعم موثر است. اما به دلیل اثرات زیانبار چربی بر سلامتی، امروزه محصولات کم چرب مورد استقبال تولید کنندگان و مصرف کنندگان قرار گرفته است. کاهش چربی سبب افت کیفیت فرآورده های گوشتی می گردد. برای جبران این افت کیفیت می توان از افزودنی هایی نظیر ژل آلوئه ورا استفاده کرد. در این پژوهش ژل آلوئه ورا جایگزین صفر، 50 و 100 درصد چربی حیوانی و روغن گیاهی در فرمولاسیون سوسیس آلمانی شد و خصوصیات فیزیکوشیمیایی، میزان انرژی، رنگ، بافت و خصوصیات حسی نمونه های سوسیس اندازه گیری گردید. بر اساس نتایج حاصله با جایگزینی ژل تفاوت معناداری در میزان خاکستر، پروتئین و pH نمونه ها ایجاد نشد (05/0<p). کاهش چربی و افزودن ژل آلوئه ورا افزایش بسیار معناداری را در میزان رطوبت و کربوهیدرات نمونه ها ایجاد کرد. همچنین مقدار چربی و انرژی فرآورده را کاهش داد (01/0≥p). شاخص زردی نمونه ها با کاهش میزان چربی کاهش یافت (01/0≥p). اثر جایگزینی چربی بر مقدار روشنایی نمونه ها معنادار بود (01/0≥p) و با کاهش چربی حیوانی فرمولاسیون، مقدار روشنایی افزایش یافت، اما با کاهش مقدار روغن گیاهی میزان روشنایی کم شد. جایگزینی چربی با ژل آلوئه ورا بر مقدار قرمزی نمونه ها اثر معناداری نداشت (05/0<p). کاهش چربی، سفتی، قابلیت جویدن، حالت صمغی و چسبندگی را کاهش داد (05/0>p)، اما بر میزان کشسانی و پیوستگی نمونه ها اثرمعنی داری نداشت (05/0<p). از نظر ارزیاب های حسی نمونه فاقد چربی حیوانی بیشترین پذیرش کلی را دارا بود.
    کلیدواژگان: جایگزین چربی، ژل آلوئه ورا، سوسیس، فرآورده های کم چرب
  • فهیمه توریان *، مریم عزیزخانی صفحات 13-24
    پذیرش مصرف آنتی اکسیدان های سنتزی به علت اثرات زیان آور آنها بر سلامتی انسان، رو به کاهش است. در نتیجه، علاقه زیادی جهت یافتن آنتی اکسیدان های طبیعی موثر وجود دارد. زنیان گیاه دارویی ارزشمند است که در طب سنتی ایران به طور گسترده مورد استفاده قرار می گیرد. در تحقیق حاضر به ارزیابی خاصیت آنتی اکسیدانی عصاره آبی و الکلی (اتانولی و متانولی) میوه گیاه زنیان در روغن کانولا پرداخته شده است. به جهت بررسی فعالیت آنتی اکسیدانی عصاره ها، از دو آزمون بررسی میزان مهارکنندگی رادیکال آزاد DPPH و سامانه بتاکاروتن/ لینولئیک اسید استفاده شد. همچنین، رفتارآنتی اکسیدانی عصاره گیاه زنیان در روغن کانولا، با اندازه گیری اعداد پراکسید و تیوباربیتوریک اسید مورد ارزیابی قرار گرفت. در آزمون بی رنگ شدن بتاکاروتن، بیشترین بازدارندگی در غلظت 2 میلی گرم بر میلی لیتر را BHT (09/0 ± 96%) نشان داد و سپس عصاره اتانولی (0/0 ± 76%) قرار داشت. سپس در سامانه ◦DPPH و بی رنگ شدن بتاکاروتن، ابتدا قدرت فعالیت آنتی اکسیدانی BHTو بعد عصاره اتانولی در سطح غلظتی 400 و ppm 600 قرار گرفت .در آزمون گرمخانه گذاری، عصاره ها توانایی جلوگیری از تولید محصولات اولیه و ثانویه اکسیداسیون، در روغن کانولا را داشتند. همچنین نتایج آماری نشان داد که عصاره اتانولی در غلظت ppm600 تفاوت معناداری در عدد پراکسید و TBARS در مقایسه با غلظت ppm200 BHT نداشته (05/0p>) ولی عصاره آبی و متانولی فعالیت آنتی اکسیدانی پایین تری داشتند (05/0p<) .با توجه به نتایج به دست آمده، می توان از گیاه زنیان به عنوان آنتی اکسیدان طبیعی در مواد غذایی به ویژه روغن های خوراکی استفاده کرد.
    کلیدواژگان: زنیان، عصاره، فعالیت آنتی اکسیدانی، روغن کانولا
  • نیلوفر اسمعیلی خانی، شادی مهدی خانی، علی محمدی * صفحات 25-35
    کیفیت گوشت همیشه برای مصرف کنندگان آن بسیار مهم می باشد. تردکردن گوشت یکی از راه های بهبود کیفیت در گوشت و فرآورده های آن می باشد. در این مطالعه اثر سه سطح (0025/0، 005/0 و 01/0 درصد) از پروتئاز تولیدی به وسیله ی آسپرژیلوس نایجر بر میزان تردی گوشت طی 28 روز نگهداری، در دمای 4 درجه سانتی گراد مورد بررسی قرار گرفت. سپس تیمارها از نظر ویژگی های فیزیکوشیمیایی و حسی با نمونه شاهد ارزیابی شدند. در این مطالعه از آزمون های پروتئین محلول کل، محتوای رطوبتی، میزان pH، رنگ سنجی، سفتی بافت، ظرفیت نگهداری آب و آزمون حسی جهت بررسی پارامترهای کیفی گوشت استفاده شد. نتایج آزمون های انجام شده نشان داد که پروتئین های محلول، pH و محتوای رطوبتی تیمارهای تولید شده، با افزایش غلظت آنزیم از 0025/0 به 01/0 درصد به طور معنی داری افزایش یافته است (P<0/05)، اما سفتی بافت نمونه ها کاهش یافت. همچنین نتایج نشان داد که ظرفیت نگهداری آب تمامی تیمارها در طی زمان مدت نگهداری کاهش یافته است ولی تیمار 01/0 آنزیم بیشترین ظرفیت نگهداری را در پایان مطالعه نشان داد. شاخص روشنایی (L*) و شاخص زردی (b*) تیمارها در مدت زمان نگهداری کاهش ولی شاخص قرمزی (a*) افزایش یافت، پروتئاز قارچی در طی زمان نگهداری سبب ایجاد رنگ قرمز تیره در نمونه های گوشت شد. در خصوص ویژگی های حسی تیمار حاوی 0025/0 درصد آنزیم قارچی و شاهد پذیرش قابل قبول تری را نشان دادند.
    کلیدواژگان: آسپرژیلوس نایجر، پروتئاز، تردی گوشت، pH
  • مهسان ایرجی فر، محمد جواد وریدی *، مهدی وریدی، یونس زاهدی صفحات 37-54
    در این تحقیق اثر ماریناد اسید لاکتیک ( در چهار غلظت صفر، 5/0، 1 و 5/1 درصد) وکلرید سدیم (2 درصد) طی زمان های غوطه وری صفر، 24، 48 و 72 بر ویژگی های بافتی، حسی و الگوی پروتئولیز عضله دو سر ران (Biceps femoris) شتر یک کوهانه بررسی شد. طول سارکومر، شاخص تجزیه میوفیبریل، نیروی برشی وارنر- براتزلر، میزان کلاژن، آنالیز حسی و الگوی پروتئولیز پروتئین های میوفیبریلی با استفاده ازSDS-PAGE مورد بررسی قرار گرفت. نتایج نشان داد با افزایش غلظت اسید و زمان نگهداری نمونه ها، میزان نیروی برشی و کلاژن کاهش پیدا کرد درحالی که شاخص تجزیه میوفیبریل و طول سارکومر افزایش یافت. همچنین نتایج حاصل از SDS-PAGE نشان داد که اثر زمان بر مساحت باند (به عنوان شاخصی از پروتئولیز) زنجیره سنگین میوزین معنی دار نبود (05/0<p). درحالی که غلظت اسید اثر افزایشی معنی داری بر مساحت زنجیره سنگین داشت (05/0>p). در رابطه با پروتئین های c،α -اکتینین و اکتین هم غلظت و هم زمان اثر معنی دار و افزایشی در مساحت داشتند (05/0>p)، اما بر سایر باندها اثر معنی داری گزارش نشد (05/0<p). ارزیابی حسی نیز حاکی از تاثیر معنی دار ماریناد بر تردی و پذیرش کلی گوشت بود، به طوری که غلظت 5/1 درصد اسید بیشترین پذیرش و تردی را نشان داد (05/0>p). نتایج حاصل از این مطالعه نشان داد که ماریناد اسید لاکتیک می تواند به عنوان یک روش موثر بر ویژگی های بافتی و پروتئولیز عضله دوسر ران شتر به کار رود.
    کلیدواژگان: اسید لاکتیک، ویژگی های بافتی، شتر، عضله دوسر ران
  • مریم زائری، سیمین اسداللهی *، مهناز هاشمی روان صفحات 55-65
    کیک یکی از فرآورده های مهم غلات و محصولی از آرد گندم بوده که دارای انواع مختلف و با کالری های متفاوت می باشد. جایگزین های چربی ترکیباتی هستند که جهت تامین تمام یا برخی از خواص چربی به کار می روند در حالی که نسبت به آن کالری کمتری تولید می کنند. قابل توجه این که در محصولات قنادی، جایگزین‏های چربی بر پایه کربوهیدرات، به علت دارا بودن مزایای فنی و اقتصادی، در مقایسه با سایر جایگزین ها، بیشتر مورد استفاده قرار می گیرند که یکی از این جایگزین ها، صمغ ها می باشند. در همین راستا در تحقیق حاضر، جایگزین کردن بخشی از چربی با صمغ های دانه لوکاست و زانتان هرکدام به تنهایی در سطوح 2/0، 4/0 و 6/0 درصد، مخلوط آن ها به طور مساوی شامل 1/0، 2/0 و 3/0 درصد همچنین مخلوط نامساوی آن ها به صورت (2/0 و 4/0) و (4/0 و 2/0) مورد بررسی قرار گرفت. طبق نتایج، تیمار حاوی (6/0درصد صمغ زانتان) از بیشترین مقدار حجم، ارتفاع، رطوبت و تیمار شاهد از کمترین مقدار چربی و ویسکوزیته برخوردار بودند. همچنین تیمار حاوی (6/0 درصد صمغ لوکاست) دارای کمترین دانسیته اما تیمار شاهد دارای بیشترین مقدار صفت مذکور بودند. با توجه به نتایج آزمون بیاتی در روزهای اول، هفتم و پانزدهم، بیشترین مقدار سفتی بافت در تیمار شاهد اما کمترین مقدار آن در تیمار حاوی(6/0 درصد صمغ زانتان) مشاهده گردید. با لحاظ نمودن کلیه صفات، تیمار حاوی ترکیبی از 2/0 درصد صمغ لوکاست و 4/0 درصد صمغ زانتان، به عنوان مطلوب ترین تیمار از نظر ویژگی های فیزیکوشیمیایی و حسی نسبت به شاهد و سایر تیمارها معرفی گردید.
    کلیدواژگان: کیک روغنی، جایگزین چربی، صمغ لوکاست، صمغ زانتان
  • سپیده آریایی مجد، مانیا صالحی فر * صفحات 67-76
    یکی از فرآورده های تخمیری حائز اهمیت در سرتا سر جهان دونات تخمیری است که مشابه نان پس از طی مراحل تخمیر، تقسیم، شکل دهی و استراحت خمیر به جای پخت در فر در روغن سرخ می شود. بنابراین بهبود کیفیت و افزایش ماندگاری آن با استفاده از افزودنی های غذایی بسیار حائز اهمیت می باشد. هدف از این مطالعه ارزیابی امکان تولید دونات فراسودمند حاوی عصاره هیدروالکلی فلفل شیرین (5/1، 5/2و% 5/3) و عصاره هیدروالکلی سیب (8، 10 و 12%) در 100 گرم آرد بود. بر این اساس تاثیر عصاره های فلفل شیرین و سیب بر خواص فارینوگرافی خمیر و ویژگی های فیزیکوشیمیایی دونات شامل رطوبت، سختی بافت در روز اول و سوم و رنگ و همچنین آزمون ماندگاری شامل اندیس پراکسید در روزهای اول، پانزدهم و سی ام، مورد آزمون قرار گرفت. افزایش سطوح به کارگیری عصاره های فلفل شیرین و سیب در فرمولاسیون دونات به طور مستقیم میزان رطوبت را افزایش داد. همچنین مشخص شد که با افزایش درصد عصاره ها میزان سختی بافت و روشنایی رنگ و عدد پراکسید کاهش یافت. نتایج آزمون فارینوگرافی نشان داد که افزایش سطوح استفاده از عصاره ها ویژگی های فارینوگرافی خمیر را تضعیف کرد. طبق بررسی و ارزیابی های صورت گرفته شرایط بهینه شامل استفاده از 95/11 درصد عصاره سیب و 3/3 درصد عصاره فلفل شیرین در فرمولاسیون خمیر دونات بود.
    کلیدواژگان: دونات، عصاره فلفل شیرین، عصاره سیب، خواص فیزیکوشیمیایی، رئولوژی
  • پیوند قلی پور شهرکی، محمد فاضل * صفحات 77-89
    خشک کردن محصولات کشاورزی همواره یکی از قدیمی ترین و بهترین روش های ذخیره مواد غذایی است. برای بالا بردن کیفیت انجیر، باید فرایند خشک کردن بهینه سازی شود. پوشش های خوراکی به منظور افزایش کیفیت مواد غذایی، مورد استفاده قرار می گیرند. در این تحقیق اثر پارامترهای دما، سرعت جریان هوا و روش پوشش دهی محصول بر کیفیت خشک شدن انجیر رقم سبز با استفاده از دستگاه خشک کن کابینتی مورد بررسی قرار گرفت. متغیرها شامل 3 سطح پوشش (آب مقطر به عنوان شاهد بدون پوشش، محلول کربوکسی متیل سلولز (CMC) 1% حاوی 25/0 گرم بر لیتر گلیسرول، محلولCMC 1% حاوی 25/0 گرم بر لیتر گلیسرول و 2% اسید آسکوربیک)، 3 سطح دمای خشک کردن (60، 70 و 80 درجه سانتی گراد) و 3 سطح سرعت جریان هوای خشک (5/0، 1 و 5/1 متر بر ثانیه) بود. نتایج به دست آمده نشان داد که روش پوشش دهی، سرعت جریان هوا و دما چروکیدگی، جذب مجدد آب، سفتی، pH، آنتی اکسیدان، فلاونوئید و شاخصه های رنگی را تحت تاثیر قرار دادند. میزان چروکیدگی با استفاده از پوشش CMC%08/4 افزایش یافت ولی میزان جذب مجدد آب به پوشش دهی بستگی نداشت. چروکیدگی در سرعت جریان 1 متر بر ثانیه %92/2 افزایش پیدا کرد. نتایج حاصله نشان داد که با افزایش دما و سرعت جریان هوا جذب مجدد آب کاهش یافت. به طوری که در دمای 70 و 80 درجه سانتی گراد جذب مجدد آب به ترتیب %89/3 و %77/7 شد و با افزایش سرعت جریان هوا %45/2 کاهش یافت. با افزایش درجه حرارت خشک کردن به 70 و 80 درجه سانتی گراد، سفتی 15/2 و 30/5 نیوتون افزایش پیدا کرد. pH در نمونه های پوشش داده شده با CMC و CMC-اسید آسکوربیک کاهش یافت. ظرفیت آنتی اکسیدانی در پوشش CMC- اسید آسکوربیک بالاتر از شاهد و پوشش CMC بود. میزان فلاونوئید در پوشش CMC- اسید آسکوربیک بیش تر از نمونه شاهد و نمونه شاهد بیش تر از نمونه با پوشش CMC مشاهده شد. استفاده از پوشش CMC و CMC- اسید آسکوربیک به ترتیب به میزان %61/2 و %98/1 با افزایش روشنایی همراه بود. با افزایش سرعت جریان هوا به 1 و 5/1 متر بر ثانیه میزان روشنایی نمونه ها %008/3 و %42/11 افزایش یافت. افزایش دما کاهش میزان L* را موجب شد. پوشش ترکیبی CMC- اسید آسکوربیک باعث افزایش a*به میزان %44/1 گردید. همچنین مشاهده شد، میزان b* در نمونه CMC-اسید آسکوربیک(%20/0) و CMC (%05/0) نسبت به نمونه شاهد بیش تر بوده است. افزایش سرعت جریان هوا و دما با b* رابطه مستقیمی داشت. به طوری که b* در سرعت جریان هوا 1 و 5/1 متر بر ثانیه %48/0 و %41/1 و در دمای 70 و 80 درجه سانتی گراد %41/2 و %83/3 شد.
    کلیدواژگان: انجیر، پوشش خوراکی، کربوکسی متیل سلولز، خشک کردن
  • بهینه سازی استخراج پکتین از تفاله گوجه فرنگی به کمک امواج فراصوت با استفاده از روش سطح پاسخ
    مهدی زاهدی، زهره حمیدی، حسن احمدی گاولیقی صفحات 91-106
    پکتین هتروپلی ساکارید ساختاری دیواره سلولی گیاهان است و پس از استخراج به عنوان عامل ژله کننده در محصولات غذایی استفاده می شود. این پژوهش با هدف بهینه سازی و ارزیابی کمی و کیفی استخراج پکتین از تفاله گوجه فرنگی به عنوان یکی از عمده ترین ضایعات صنایع تبدیلی کشور انجام گرفت. همچنین از امواج فراصوت به عنوان روشی نوین و کارآمد جهت استخراج پکتین استفاده شد. راندمان استخراج و درصد گالاکتورونیک اسید پکتین در دامنه pH (5/2-5/1)، دمای (C°90-60)، زمان استخراج (30-6 دقیقه) و چگالی توان فراصوت (W/ml3/0-15/0) با روش سطح پاسخ (RSM) بهینه سازی شد. همچنین درجه استری، ویسکوزیته ذاتی و خصوصیات امولسیفایری پکتین تفاله گوجه فرنگی در شرایط بهینه تعیین گردید. با توجه به نتایج حاصل، بیشترین راندمان (5/10 %) و درجه خلوص پکتین (65 %) در شرایط pH برابر 2، دمای C°86، زمان 30 دقیقه و چگالی توان فراصوت W/ml 3/0 به دست آمد. تحت شرایط بهینه استخراج، پکتین با درجه استری و ویسکوزیته ذاتی به ترتیب 76 % و dl/g 6/2 حاصل گردید. خصوصیات امولسیفایری پکتین استخراج شده در نقطه بهینه در سه سطح غلظت پکتین 25/0، 5/0 و 1 % مورد بررسی قرار گرفت. بیشترین فعالیت امولسیفایری (5/87%) در غلظت 1 درصد حاصل شد. با نگه داری امولسیون در دو دمای C°4 وC°23، میزان پایداری امولسیون قابل توجهی(99 %) در غلظت 25/0% در دوره زمانی سی روزه به دست آمد. نتایج نشان داد، تفاله گوجه فرنگی می تواند به عنوان منبع ارزان قیمتی از پکتین مورد استفاده قرار گیرد.
    کلیدواژگان: استخراج پکتین، تفاله گوجه فرنگی، امواج فراصوت، فعالیت امولسیفایری
  • نفیسه رواتاب، سیمین اسداللهی *، محمدرضا اسحاقی صفحات 107-120
    شکلات شیری یکی از پرمصرف ترین شکلات هایی است که ترکیبات اصلی آن شامل پودرکاکائو، شکر، کره کاکائو و پودر شیر خشک می باشد. هدف از تحقیق حاضر این است که با استفاده از پودر دانه بزرک به عنوان جایگزین پودر و کره کاکائو، شکلاتی با میزان کالری پایین و همچنین به واسطه میزان بالای امگا- 3 در پودر بزرک، شکلاتی غنی شده با خواص درمانی تولید شود. تیمارهای پژوهش شامل شاهد، L10، L20، L30 و L40 به ترتیب با مقادیر صفر، 10، 20، 30 و 40 درصد پودر بزرک بودند که جایگزین کره و پودر کاکائو، شیر خشک و شکر شدند. آزمایش های انجام شده شامل بررسی خواص فیزیکوشیمیایی (قند، چربی، اسیدیته، رطوبت، پراکسید، خاکستر، اندازه ذرات، ویسکوزیته ظاهری و سنجش میزان امگا-3)، بافت سنجی و حسی بودند. طبق نتایج، بین تیمارهای مختلف از نظر میزان چربی، قند، اندازه ذرات، ویسکوزیته ظاهری، مقدار نفوذپذیری، پذیرش دهانی، پذیرش بویایی، پذیرش بافت، صدای شکست، پذیرش رنگ و باقی مانده امگا-3، اختلاف معنی دار مشاهده شد. در صورتی که در مقدار خاکستر، پراکسید، اسیدیته و رطوبت این اختلاف معنی دار نبود. مطابق نتایج، تیمار L30 به جهت دارا بودن امگا 3 و همچنین مطلوبیت در ویژگی‎ های بافتی و خواص حسی به عنوان تیمار برتر معرفی گردید.
    کلیدواژگان: شکلات شیری، پودر بزرک، امگا-3، خواص فیزیکوشیمیایی
  • هانیه عارفی، حجت کاراژیان * صفحات 121-131
    موس نوعی دسر هوا داده شده با ساختار کفی پایدار می باشد که مواد اصلی آن از به هم زدن سفیده تخم مرغ، خامه، کره، شکر، کاکائو تشکیل می شود. سفیده تخم مرغ اصلی ترین ماده مورد استفاده در تهیه موس است و به دلیل این که خاصیت کف کنندگی و هوادهی بسیار بالایی دارد، هدف یافتن جایگزین مناسب برای سفیده تخم مرغ به عنوان کف کنندگی و هوادهی می باشد. شیرین بیان یکی از مهم ترین گیاهان دارویی از لحاظ اقتصادی است که به صورت گسترده مورد پژوهش قرار گرفته است. به دلیل خواص فیزیکی، کف کنندگی شیرین بیان و هوادهی در محصولات، کاربردهای متنوعی در داروسازی و صنایع غذایی پیدا کرده است. استفاده از منابع گیاهی در رژیم غذایی روزانه بیش از پیش توصیه می شود. در این پژوهش ویژگی های فیزیکوشیمیایی و بافتی موس حاصل از جایگزینی تخم مرغ با سطوح مختلف شیرین بیان مورد ارزیابی قرار گرفت. شیرین بیان در چهار سطح 5/12، 25، 5/37 و 50 درصد جایگزین تخم مرغ در فرمولاسیون موس شد. رطوبت، افزایش حجم، دانسیته، فاز هوا، شاخص همزدن، شاخص دوام کف و شاخص های بافت مورد بررسی قرار گرفت. نتایج نشان داد که سطوح مختلف جایگزینی شیرین بیان کلیه خصوصیات را تحت تاثیر قرار داد، به طوری که با افزایش نسبت جایگزینی مقادیر رطوبت، افزایش حجم، شاخص دوام کف، فرایند هم زدن، فاز هوا نسبت به شاهد کاهش و دانسیته، قابلیت ارتجاع پذیری، قابلیت جویدن، پیوستگی وچسبندگی افزایش پیدا کرد. با توجه به نتایج ذکر شده، با استفاده از جایگزینی شیرین بیان در فرمولاسیون موس، می توان تا حدودی کیفیت محصول نهایی را تغییر داد.
    کلیدواژگان: موس، سفیده تخم مرغ، شیرین بیان، ویژگی های بافتی، خصوصیات فیزیکوشیمیایی
  • فرشته غلامی، سارا انصاری * صفحات 133-144
    در این تحقیق، برشته کردن دانه های سویا به دو روش آون و مادون قرمز انجام شد و از روش سطح پاسخ به منظور بررسی اثر هر یک از فرایندهای مذکور بر میزان رطوبت، ترکیبات فنولی، فعالیت آنتی اکسیدانی، سفتی و تغییرات رنگ دانه های سویا استفاده گردید. معادله پیشنهادی جهت بررسی اثر دما و زمان برشته کردن بر میزان کاهش رطوبت در روش آون درجه دوم و در روش مادون قرمز خطی بوده و اثر آنها معنی دار (05/0>p) گزارش شد. در هر دو روش، میزان ترکیبات فنولی کل و فعالیت آنتی اکسیدانی از معادله درجه دوم پیروی کرده و اثر فاکتورهای مربوطه هم معنی دار (05/0>p) بود و با افزایش دما و زمان، میزان پاسخ های فوق نیز افزایش یافت. سفتی و تغییرات رنگی در روش آون از معادله درجه یک و در روش مادون قرمز تنها تغییرات رنگی از معادله درجه اول پیروی کردند. اثر پارامترهای مربوطه در کلیه مدل های پیشنهادی معنی دار بود. شرایط بهینه برای برشته کردن دانه های سویا با آون و مادون قرمز به ترتیب °C223 در 13 دقیقه و °C231 در 11 دقیقه محاسبه گردید. در شرایط بهینه مقادیر رطوبت، ترکیبات فنولی کل، فعالیت آنتی اکسیدانی، سفتی و تغییرات رنگی اندازه گیری شده به ترتیب برای روش آون و مادون قرمز عبارتند از: (10/1، 53/4، 75/42، 03/9 و 93/4) و (58/1، 93/4، 85/47، 20/6 و 79/4). با توجه به نتایج، روش مادون قرمز در مقایسه با آون می تواند به عنوان یک روش جایگزین جهت برشته کردن دانه های سویا معرفی گردد.
    کلیدواژگان: دانه سویا، برشته کردن، مادون قرمز، آون، ویژگی های فیزیکوشیمیایی
  • عبدالمجید میرزاعلیان دستجردی *، مریم هاشمی، احمد شاکر اردکانی، سید حسین میردهقان صفحات 145-157
    پسته از محصولات مهم خشکباری و بومی ایران است که به خاطر کیفیت عالی از اهمیت اقتصادی و صادراتی ویژ‎ه‎ای برخوردار است. در این مطالعه، تاثیر فیلم‎های بسته‎بندی انعطاف‎پذیر روی برخی پارامترهای کیفی پسته خشک طی انبارمانی در دمای 3±20 درجه سانتی گراد و رطوبت 65-60 درصد به مدت 12 ماه مورد بررسی قرار گرفت. نمونه‎های 200 گرمی پسته در شش نوع فیلم‎ شامل پلاستیک تک لایه با جنس پلی‎اتیلن (PE)، پلاستیک دو لایه با ترکیب پلی‎آمید متالایز شده و پلی‎اتیلن اکسترودر (PA-ONM/PE ex)، پلاستیک سه لایه با ترکیب پلی‎استر، ‎پلی‎اور‎تان و پلی‎اتیلن (PEs/PU/PE)، پلاستیک سه لایه با ترکیب پلی‎پروپیلن‎کست، ‎پلی‎اورتان و پلی‎استر (CPP/PU/PEs)، پلاستیک پنج لایه با ترکیب پلی‎آمید، اتیلن‎وینیل‎الکل، دو لایه پلیمر چسبی اکستروژن و پلی‎اتیلن (PA/EVOH/Tie/Tie/PE)، پلاستیک هفت لایه با ترکیب پلی‎اتیلن، دو لایه اتیلن‎وینیل‎الکل، دو لایه پلیمر چسبی اکستروژن، پلی‎آمید و پلی‎اتیلن‎اکسترودر (PE/EVOH/EVOH/Tie/Tie/PA/PE ex) بسته‎بندی شدند و تیمار بدون پوشش به‎عنوان شاهد بود. آزمایش به صورت فاکتوریل در قالب طرح کاملا تصادفی با سه تکرار انجام و تجزیه و تحلیل داده‏‎ها با استفاده از نرم افزار9.1.3 SAS و مقایسه میانگین‎ها از طریق آزمون چنددامنه‎ای دانکن انجام گرفت. نتایج نشان داد که کاربرد پوشش پلیمری دو و هفت لایه در مقایسه با شاهد افت وزن، میزان اسید چرب آزاد و پراکسید کمتری طی دوره انبارمانی نشان دادند. همچنین نمونه های بسته‎بندی شده در این دو پوشش به ترتیب با مقدار 952/8 و 953/8 درصد دارای بالاترین میزان کربوهیدرات و نیز بالاترین نمره‎دهی برای پارامترهای ارزیابی حسی در پایان دوره انباری بودند. پس از یک سال نگهداری، میزان سفتی مغز نمونه‎های موجود در پوشش‎‎های دو و هفت لایه (با میانگین 792/2 و 659/2 کیلوگرم نیرو) نیز تفاوت معنی‎داری را در مقایسه با شاهد (211/3 کیلوگرم نیرو) نشان دادند. در مجموع استفاده از پوشش‎های پلیمری دو و هفت لایه تاثیر معنی‎داری در حفظ کیفیت ظاهری و غذایی پسته، نسبت به شاهد و سایر پوشش‎های پلیمری طی دور انباری 12 ماهه داشتند.
    کلیدواژگان: بسته‎بندی، پسته احمد آقایی، پوشش پلیمری، دوره انبارمانی، کیفیت
  • ندا درخشان، علی اکبر شکوهیان *، بهرام فتحی آچاچلویی صفحات 159-170
    استفاده از ترکیبات طبیعی جهت حفظ سلامتی انسان و امنیت غذایی، به عنوان نگهدارنده محصولات غذایی روبه گسترش است. هدف از انجام پژوهش حاضر بررسی امکان استفاده از پوشش پوترسین در چهار سطح (صفر و 2، 4، 6 میلی مولار)، ژل آلوئه ورا در چهار سطح (صفر، 15، 30 و 45 درصد) و تاثیر زمان نگهداری (15، 30 و 45 روز) برای میوه هلو بوده است. پس از پوشش دهی میوه ها در دمای 1- درجه سانتی گراد و رطوبت 95-90٪، در سردخانه نگهداری شدند. اندازه گیری شاخص های میزان ویتامین ث، مواد جامد محلول، اسیدیته کل، فنل کل، کاروتنوئیدها و فلاونوئیدها، صورت گرفت. بر اساس جدول تجزیه واریانس، اثرات سه گانه تیمارها در تمامی شاخص ها در سطح احتمال 1% معنی دار بودند. نتایج نشان دادند که در صفات اسیدیته کل (84/0 درصد) و فلاونوئیدها (23/50 میلی گرم در یک گرم وزن تر) بیش ترین مقدار در پوشش ترکیبی پوترسین 6 میلی مولار و آلوئه ورا 15% به دست آمد. مواد جامد محلول بیشتر در پوشش ترکیبی پوترسین 2 میلی مولار و آلوئه ورا 45% مشاهده شد (18/15 درصد بریکس). بیش ترین مقدار ویتامین ث (89/10 میلی گرم اسید آسکوربیک در 100 گرم نمونه در 15 روز اول) و کاروتنوئیدها (86/94 میلی گرم بر گرم وزن تر نمونه) در پوشش ترکیبی پوترسین 6 میلی مولار و آلوئه ورا 30% حاصل شد.
    کلیدواژگان: اسیدیته، پس از برداشت، پوشش دهی، فلاونوئید، فنل، کاروتنوئید
  • فاطمه سادات میرزا خلیلی، پیمان رجایی*، مهناز هاشمی روان صفحات 171-180
    امروزه جایگزینی نگهدارنده ها و افزودنی های شیمیایی با انواع طبیعی آن ها که خاصیت ضدمیکروبی و آنتی اکسیدانی دارند، متداول شده است. در این راستا در تحقیق حاضر امکان تولید نوشابه گازدار زعفرانی مورد بررسی قرار گرفت. جهت تهیه تیمارها از سه سطح زعفران (6/0، 2 و 4%) و سه سطح شکر (65، 70 و 75%) استفاده گردید. طبق نتایج، با افزایش درصد شکر و عصاره زعفران، میزان بریکس، اسیدیته، ماده خشک، قند کل، خاکستر در نوشیدنی به شکل معنی داری افزایش یافت اما pH روند کاهشی نشان داد. قابل توجه این که اختلاف بین وزن مخصوص نمونه ها معنی دار نبود. همچنین با افزودن منابع قندی، میزان باکتری مزوفیل در محدوده استاندارد افزایش یافت به گونه ای که بیشترین مقدار آن در نمونه حاوی 70% شکر مشاهده گردید. در مجموع، تیمار حاوی (75% شکر و 2% عصاره زعفران) از مطلوب ترین خواص فیزیکوشیمیایی، میکروبی و حسی برخوردار بود.
    کلیدواژگان: نوشابه گازدار، عصاره زعفران، خواص کیفی
  • بهارک حساس، لیلا ناطقی *، علیرضا شهاب لواسانی صفحات 181-198
    پنیر کوزه ، نوعی پنیر سخت می باشد که به صورت سنتی در نواحی غربی ایران از شیر خام گاو، گوسفند و گاهی بز تولید می شود. دوره رسیدگی این پنیر درون کوزه های سفالی داخل خاک سپری می شود، لذا دارای مجموعه ای از واریته های میکروارگانیسم ها بوده، بنابراین از ویژگی های حسی منحصر به فردی برخوردار است. با این حال، موضوع انتقال برخی باکتری های بیماری زا در این فرآورده و نیز درصد بالای چربی آن از دیدگاه سلامت عمومی بسیار قابل اهمیت است. لذا هدف کلی از این پژوهش بررسی خصوصیات فیزیکوشیمیایی، ضد میکروبی و حسی پنیر کوزه ای کم چرب (تهیه شده از شیر 5/1% چربی) حاوی پودر بتاگلوکان در غلظت های (25/0، 5/0 و 1%) و عصاره اتانولی پونه کوهی در غلظت های (1/0، 2/0 و 3/0%) و مقایسه آن با نمونه پنیر شاهد (تهیه شده از شیر 3% چربی) پس از طی 60 روز نگهداری بود. نتایج بررسی ضد میکروبی نشان داد استفاده از بتاگلوکان اثر معنی داری روی خواص ضدمیکروبی تیمارهای مورد بررسی نداشت و استفاده از عصاره اتانولی پونه و افزایش غلظت آن اثر معنی داری بر افزایش خواص ضدمیکروبی تیمارهای مورد آزمون داشت. مطابق با نتایج پس از طی60 روز نگهداری، تیمار حاوی 3/0 درصد عصاره اتانولی پونه در مقایسه با سایر تیمارها و نمونه شاهد بیشترین کاهش شمارش کلی میکروارگانیسم ها، لاکتوباسیلوس ها، کپک و مخمر، کلی فرم ها، اشرشیاکلی و استافیلوکوکوس اورئوس را نشان داد. نتایج بررسی خصوصیات فیزیکوشیمیایی نشان داد میزان پروتئین، چربی، اسیدیته و ازت محلول در آب تمامی تیمارهای مورد آزمون طی دوره نگهداری افزایش و pH و رطوبت و سختی بافت نمونه ها به طور معنی داری )05/0≥p) کاهش یافت. نتایج ارزیابی حسی پنیر نشان داد که تیمار حاوی 5/0 درصد بتاگلوکان و 3/0درصد عصاره اتانولی پونه از بالاترین قابلیت پذیرش حسی برخوردار بود. بنابراین با استفاده از 5/0درصد بتاگلوکان و 3/0درصد عصاره اتانولی پونه در فرمولاسیون پنیر کوزه ای کم چرب می توان، پنیری ایمن با بار میکروبی در حد استاندارد و بافت مطلوب در مقایسه با نمونه شاهد تولید نمود.
    کلیدواژگان: پنیر کوزه ای، بتاگلوکان، عصاره اتانولی پونه
  • مهساسادات رضوی، عبدالله گل محمدی * صفحات 199-210
    در تحقیق حاضر برخی خواص فیزیکی و مکانیکی گلابی رقم درگزی بررسی شد. برای تعیین خواص مکانیکی از دستگاه آزمون جامع کشش فشار استفاده شد. آزمایش ها در پنج سطح نیرویی مختلف (40، 50، 60، 70 و 80 نیوتن) و به صورت آزمون بارگذاری- بار برداری تحت سرعت ثابت mm/min 10 انجام شد. به ازای هر سطح نیرو سه تکرار درنظرگرفته شد. نتایج بررسی نشان داد که با افزایش نیروی بارگذاری، مقادیر انرژی بارگذاری، انرژی بار برداری، پسماند مکانیکی و اتلاف پسماند مکانیکی افزایش می یابد. همچنین، مشاهده شد با افزایش درجه کشسانی و شعاع انحناء نمونه در ناحیه بارگذاری، به ترتیب اتلاف پسماند مکانیکی و انرژی کرنشی کاهش می یابد. درجه کشسانی را می توان به عنوان شاخصی برای بیان میزان حساسیت میوه گلابی در نظر گرفت.نتایج مربوط به خواص فیزیکی نمونه ها شامل؛ میانگین طول، قطر میانگین، جرم، حجم،جرم مخصوص واقعی و حجمی، تخلخل و ضریب بسته بندی به ترتیب برابر با 162/84، mm 729/73، g 8742/188، cm3 4037/185، g/ cm3 01899/1 و g/ cm3 42759/0، 92009/57 و 42088/0 به دست آمد. همچنین بیش ترین و کمترین شعاع انحناء به ترتیب در جناح گونه و ساقه میوه با مقادیر 701/77 و mm 633/24 می باشند.
    کلیدواژگان: بارگذاری- بار برداری، انرژی کرنشی، اتلاف پسماند مکانیکی، حالت ارتجاعی، درجه کشسانی
  • کوثر کاکایی، محمد نوشاد، بهزاد ناصحی *، محمد‍ حجتی، شهرام بیرقی طوسی صفحات 211-221
    بهبود ارزش تغذیه ای اسنک ها به عنوان یکی از مهم ترین و پرمصرف ترین میان وعده ها در دنیا، امری ضروری می باشد. بنابراین هدف از این پژوهش، بررسی تاثیر افزودن پودر هسته انار (8/11 درصد) به عنوان منبع فیبر بر ویژگی های فیزیکوشیمیایی اسنک ها در طی (صفر، 30 و 60) روز انبارمانی بود. برای ارزیابی تاثیر افزودن پودر هسته انار بر ویژگی های اسنک ها، مقدار چربی، پروتئین، ترکیبات فنولی، خاصیت آنتی اکسیدانی، چگالی، سفتی، شاخص جذب روغن، شاخص حلالیت، مقدار فیبر نامحلول، محتوی رطوبتی، شاخص جذب آب و ریزساختمان اسنک های تولید شده مورد بررسی قرار گرفت. نتایج این پژوهش نشان داد که افزودن پودر هسته انار سبب افزایش حلالیت، سفتی، دانسیته، شاخص رنگی a*، ترکیبات فنل کل، خاصیت آنتی‎اکسیدانی و ارزش تغذیه‎ای (از نظر میزان آهن، روی، فیبر محلول و نامحلول، پروتئین و چربی) در نمونه ها شد. در حالی که میزان محتوی رطوبتی، شاخص جذب آب، شاخص های رنگی L* و b* و فعالیت آبی نمونه ها کاهش یافت. همچنین افزودن پودر هسته انار سبب کاهش تخلخل و ایجاد حفرات ناهمگن و نامنظم در ساختمان اسنک ها شد. افزایش مدت زمان ماندگاری سبب افزایش محتوای رطوبتی، سفتی و شاخص های L* و b* و کاهش میزان ترکیبات فنلی و خاصیت آنتی اکسیدانی در نمونه ها شد. بر اساس نتایج به دست آمده از این پژوهش، می توان از پودر هسته انار به عنوان منبع فراسومند برای افزایش خواص عملکرای اسنک ها استفاده کرد.
    کلیدواژگان: زمان ماندگاری، اسنک اکسترود (حجیم) شده، پودرهسته انار، خصوصیات فیزیکوشیمیایی
  • مهسا علیخانی فرادنبه، رضا اسماعیل زاده کناری *، مریم قادری قهفرخی صفحات 223-233
    گیاهان منبع غنی از ترکیبات فنولی هستندکه مهمترین آنتی اکسیدان های طبیعی به شمار می آیند. آنتی اکسیدان ها از عوامل اصلی خنثی کننده رادیکال های آزاد می باشند، که از شیوع بیماری های مزمن و تخریب بسیاری از مواد غذایی جلوگیری می کنند. این ترکیبات از پوست کیوی نیز قابل استخراج هستند. پس از تهیه پودر پوست کیوی، عصاره ها به دو روش پروب و حمام فراصوت استخراج شدند. ابتدا میزان فنول و فلاونوئید کل عصاره ها اندازهگیری و بعد برای ارزیابی خواص آنتی اکسیدانی عصاره های استخراج شده از دو روش دی فنیل پیکریلهیدرازیل (DPPH) و قدرت احیاکنندگی (FRAP) استفاده و با غلظت 1/0 میلی گرم در میلی لیتر آنتی اکسیدان مصنوعی TBHQ مقایسه شد. نتایج نشان داد که میزان فنول و فلاونوئید کل در عصاره استخراج UPAE-KP بیشتر از UBAE-KP است. نتایج آزمون به دام اندازی رادیکال های آزاد DPPH نشان داد که غلظت مهار 50% UPAE-KP و UBAE-KP به ترتیب دارای مقادیر 067/0±2/0 و 035/0±28/0 میلی گرم در میلی لیتر است. همچنین در قدرت احیاکنندگی، میزان جذب برای UPAE-KP بیشتر از UBAE-KP بود. عصارههای پوست کیوی استخراج شده با هر دو روش فراصوت، فعالیت آنتی اکسیدانی قابل قبولی را نشان دادند، با این تفاوت که UPAE-KP نسبت به UBAE-KP فعالیت آنتی اکسیدانی بالاتری را داشت. بنابراین، عصاره پوست کیوی میتواند به عنوان منبع مفیدی برای تامین آنتی اکسیدان های طبیعی باشد.
    کلیدواژگان: فراصوت، پوست کیوی، ترکیبات فنولی، فعالیت آنتی اکسیدانی
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  • Shakiba Kianiani, Mohammad Javad Varidi *, Mehdi Varidi Pages 1-11
    Introduction
    Meat and meat products contribute about 20% to human fat consumption. Fat is the main source of energy and the base of fat soluble vitamins. Besides, it improves cooking yield and water holding capacity, conserves taste and flavor of products and affects the emulsion stability, juiciness, costumer acceptability and structural and rheological properties of meat products. But Animal fat contains a relatively high amount of saturated fatty acids and cholesterol, which can increase the risk of cardiovascular disease, diabetes, cancer types and obesity. Thus, the meat industry is interested in merchandising fat-reduced meat products without neglecting the positive effects of fat on flavor and texture.
    Various researches have shown that the substitution of fat on a polysaccharides base such as fibers, starch, gums, and gels have improved and modified the texture, residual moisture and freeze stability, and decreased the price of the products.
    Aloe vera leaf gel contains about 99 – 99.5 % water and 1 - 0.5 % of the total solid content. On dry matter basis aloe vera gel consists of 55% polysaccharides, 17 % sugar, 16 % mineral, 7% protein, 4% lipids and 1% phenolic compounds (Lawless et al., 2014). The most important carbohydrates of aloe vera gel are the long chain polysaccharides, comprising glucose and mannose, known as the glucomannans [β (1, 4) – linked acetylated mannan]. All the solid content of aloe vera gel are surrounded by polysaccharide mucilage layer.
    Literature review pointed out there have been little investigations into the functionality of aloe vera gel in the emulsion meat products. According to the importance of producing low - fat meat products from one hand as well as the nutritional values and health characteristics of aloe vera gel on the other hand, this study was designed to replace the fat with aloe vera gel in the production of low - fat German sausage.
    Material and Methods
    Sausage samples containing 40% of red meat (German sausage) were produced based on the conventional plants formula. animal fat and vegetable oil replaced by 0, 50 and 100% aloe vera gel in the German sausage formulation. All samples were cooked at 90°C temperature to achieve the core temperature of 70° C, followed by cooling, they were kept in the refrigerator (4°C) until the subsequent experiments. The AOAC (2000) methods were used for measuring the moisture content, the amount of fat, ash and protein. The amount of carbohydrate was calculated based on the calculation of the total weight difference from the sum of ash, protein, fat and moisture (according to the method FAO / WHO). The amount of energy was computed based on the total amount of energy from fats, proteins and carbohydrates. To measure the pH of samples by pH meter, method of choe et al (2013) was followed. The color analysis was done on the surface of sausage cuts by chromometer. The parameters of color include L* (lightness), a* (redness) and b* (yellowness) were measured. Texture parameters include hardness(N), cohesiveness, springiness (cm), gumminess (N), chewiness (N.cm), adhesiveness were determined by texture analyzer as described by Bourne (1978). The sensory attributes were evaluated by 10 trained panelists. A five-point hedonic scale rating (1= very bad, 2=bad, 3= neither bad nor good, 4= good, 5= very good) was carried out.
    Results and Discussion
    Physicochemical properties analysis indicated significant differences among meat products (p ≤.0.01). The addition of aloe vera gel resulted a decrease in fat percentage and amount of energy, an increase in moisture and carbohydrate, but the amount of pH, protein and ash content did not change. This study showed that reducing the fat content and replacing by aloe vera gel caused a significant difference in the amount of energy (p≤.0.01).With respect to the significant contribution of fat in the production of energy, the amount of energy was reduced as expected by reducing the fat of the formulation. The results indicated that the value of L * showed the negative and positive trends with animal fat and vegetable oil changes, respectively (p≤.0.01). b* decreased by reducing the amount of fat and oil (p≤0.01), but the value of a* always remained constant (p˃0.05). The presence of aloe vera gel in sausage caused a reduction in hardness, adhesiveness and gumminess (p<0.05), while it did not affect the amount of adhesiveness and cohesiveness of samples (p˃0.05).
    The substitution of fat with aloe vera gel had a significant effect on the sensory characteristics of German sausage (p≤.0.01). By reducing fat and oil and adding aloe gel to the German sausage formulation, color acceptance score was decreased. In terms of panelists, the blank sample had the best color and the fifth sample color had the lowest score. Juiciness of the samples was increased by increasing the amount of gel. The results also showed that the fifth sample received the maximum score of juiciness. Sausages smell acceptance negatively changed by reducing the fat content and adding aloe vera gel. Third and fourth treatments got the highest texture score. Also, the third sample had the highest scores for taste and general acceptance. Chewiness analyzing showed that by increasing the amount of fat replacement the rate of this factor decreased. as well as the maximum rate of chewiness was related to the blank sample.
    Keywords: Fat replacement, Aloe Vera gel, Sausage, Low fat products
  • Fahimeh Tooryan *, Maryam Azizkhani Pages 13-24
    Introduction
    Lipids are valuable foods that operate as the medium of heat transfer to the food and susceptible to oxidation on storage and frying processes. Lipid oxidation is one of the major cause of food quality deterioration during storage for vegetable oils, fats and other food systems. The free radical are defined as any chemical species having one or more unpaired electrons is generally responsible for the deterioration and limiting the shelf life of fatty foods. Characteristic changes associated with oxidative deterioration include development of unpleasant tastes and odors as well as changes in color, specific gravity, viscosity and solubility .Moreover, the products of lipid oxidation may be potentially toxic and may lead to adverse effects such as the production of carcinogens, mutagenesis and aging. Autoxidation occurs when molecular oxygen reacts with unsaturated lipids like canola oil. Antioxidants are a group of chemicals affect the process of lipid oxidation at different stages and capable of extending the shelf life of food that contain lipids. In general, food industry have been added and applied the synthetic antioxidants such as BHA (Butylated hydroxyl anisole), BHT (Butylated hydroxyl anisole) and TBHQ (Tert-butyl hydroquinone) during the manufacturing process to retard lipid oxidation and prevent fat oxidative and rancidity. They are used to retard the development of unpleasant flavour caused by the oxidation of unsaturated fatty acids. They retard oxidation of lipids by reacting with free radicals, chelating free catalytic metals and also by acting as oxygen scavengers. However, there is concern about the safety and toxicity of synthetic antioxidants in relation to their metabolism and accumulation in body organs and tissues. Synthetic antioxidants are known among other things to cause impairment of blood clotting, lung damage and to act as tumor promoters. Consumers acceptance of synthetic antioxidants remains negative due to their perceived detrimental effect on human health like carcinogenic effects. Consequently, This has led to an increasing trend and interest in the search for effective natural antioxidant and there has been a tendency towards natural antioxidants and replace of these synthetic antioxidants with natural ones such as phenolic compounds. Finding new resources of vegetal antioxidants in order to use them in food (as an additive or alternative with artificial antioxidants) is an important research subject in the field of food science and technology.Researches on alternative natural products such as aromatic plants extract and essential oil have been extended. Phenolic compounds are defined as substances possessing a benzene ring bearing one or more hydroxyl substituents, including their functional derivatives. There are different sources of phenols such as grapes, olive oil, sorghum, beans, spices and herbs. Aromatic plants are used traditionally in various regions of Iran for their preservation and medicinal properties, in addition to enhancing the aroma and flavor of foods. Aromatic plants components that have antiradical activities were used as natural antioxidant in food and biological products. Carum copticum (C. copticum )is well known and valuable medicinal plant that is used widely in Iranian traditional medicine. In this study C. copticum ,as natural antioxidant, was added to Canola oil for improving its oxidative stability .The aim of this research was to evaluate the antioxidant properties of C. copticum extracts (aqueous and alcoholic),and its antioxidant activity in canola oil
    Materials and methods
    In this study, aqueous and alcoholic extract of C. copticum fruit was extracted as a natural antioxidant. In the first stage, the amount of phenolic compounds content in extracts were measured. Then to determine antioxidant power and activity of extracts the two methods was investigated, DPPH◦ free radical scavenging and β-carotene/linoleic acid system. Each extract at three concentrations of 200 ppm ,400ppm and 600ppm added to canola oil and storage in a period of 49 days. BHT were added to Canola oil at 100 and 200ppm. Also their oxidative stability in canola oil was investigated by measuring peroxide and thiobarbituric acid values.
    Results & discussion
    The results showed that, C. copticum has good total phenolic content and in β-caroten bleaching assay, by concentration of 2 mg/ml BHT showed the highest inhibition effect (%96 ± 0.09) and followed CE (%76±0.0). In DPPH◦ free radical scavenging and β-carotene/linoleic acid systems, the sequence of the power of antioxidant activity was BHT then CE in concentration of 400 and 600 ppm. In oven test, all extracts inhibited primary and secondary oxidation products of canola oil. Statistical results revealed that CE in concentration of 600 ppm, did not showed significant difference for PV and TBARS comparing with 200 ppm BHT(p>0.05). But CA and CM had lower antioxidant activity in comparision with 200 ppm BHT (p<0.05). Acocording to results, C. copticum is a potent antioxidant for stabilization of canola oil and can be used as a natural antioxidant. It seems that after complementary test because of appropriate antioxidant activity, C. copticum can be used as natural antioxidant in foodstuff, especially in edible oils to improve the oxidative stability of canola oil.
    Keywords: Carum copticum, extracts, antioxidant activity, canola oil
  • Nilofar Esmailikhani, Shadi Mehdikhani, Ali Mohammadi * Pages 25-35
    Introduction
    Meat quality is always very important for consumers. Tenderize meat one way to improve the quality of Meat and its products. In the study effect of three levels (0.0025, 0.005 and 0.01 percent) of protease produced by Aspergillus niger on meat tenderness during the 28 days of storage at 4 ° C were studied. Then treatments to control the physicochemical and sensory characteristics were evaluated. In this study tests the total soluble protein, moisture content, pH, colorimetric, texture analysis, water holding capacity and sensory evaluation of meat quality parameters were used. The results of the tests carried out showed that soluble proteins, pH and moisture content levels generated by increasing the enzyme from 0.0025 to 0.01 percent was significantly increased (P<0.05), But on the rigidity by increasing the enzyme decreased firmness. Results also showed that water holding capacity has decreased, but all treatments during storage period 0/01 enzyme treatment showed the highest capacity at the end. Brightness index (L *) and yellowness index (b *) during maintenance treatments reduce the redness index (a *) increased. The sensory characteristics of diet supplemented with 0.0025% of fungal enzymes and control the admission showed more acceptable. So this study using Aspergillus niger enzyme for use in to tenderize meat it considers appropriate.
    Materials and methods
    For this purpose, 4 samples of 500 grams of Rhomboideus muscle from the 1.5-year-old Holstein male calf from the Rock Company slaughterhouse were immediately prepared for killing. Samples were stored in a refrigerator at 4 ° C for 48 to 72 hours. Each muscle was maintained as a non-injectable control unit (control sample). Then injected into three other parts of the enzyme solution. Protein solution of Aspergillus Niger was obtained from the Iranian Institute of Science and Technology. Then injection of the extracts of the enzyme into the sequences by the injector with 0.01% (AN 0/01), 0.005% (AN 0/005) and 0.0025% (AN 0/0025) (Mg / 100 grams of meat) of fungal protease separately into meat pieces. The pieces of meat were treated using an injector with 4 needles in each row with 10 needles with a spacing of 2.8 cm and a pressure of 35 injections. After injection, the muscle samples were packed under vacuum and immediately stored at 4 ° C for 28 days. On the days 1, 7, 14, 21 and 28, the relevant tests were performed on the treatments. To measure the pH, 10 g of the milled meat was mixed in 90 g of deionised water. The prepared mixture was then plated with a rough filter paper (average watten-diameter of 150 mm). Finally, pH was measured using a digital pH meter. The homogeneous moisture content of the meat samples was measured using the oven method and according to AOAC standard No. 46/950. The basis of the test is based on the measurement of total nitrogen in foods, assuming that all N is a protein type and is based on the coefficients of N-to-protein conversion. To determine the protein values, use the method outlined in AOAC (1996). Used. To measure the protein, the Kjeldahl method was used by the Kjeldahl machine constructed in Japan. The color of the meat was measured by a color spectrometer (CR-300, Minolta, Co. Ltd., Japan) every seven days. White tile with b *: 1.72; a *: -0.02; L *: 97.46 is considered as reference.This test was performed to examine the tissue texture strength of the specimens by using Feismann et al. (1999) by Brookfield Engineering Laboratories, USA at 4 ± 2 ° C. In this test, a cylindrical probe with a smooth cross-section with a diameter of 12.7 mm and a speed of 1 ml / sec was used. In order to measure the water holding capacity, the amount of water extracted from the cutting surface of meat samples under 500 psi pressure and 1 minute time to the filter cassette was accurately weighed to 0.001 g and was expressed as extractable moisture content. The evaluation of sensory features in terms of five factors including hardship, substrate, texture, color and general acceptance was performed using 10 evaluated trainees by Hedonic method by completing an evaluation questionnaire. To each of the mentioned factors, the privilege was allocated from 1 to 5. The way to score was based on the fact that the number 5 represents the highest score and the number 1 represents the lowest score all experiments were performed in a completely randomized design with three replications. Means were compared using SPSS 21 and based on Duncan's tests at 5% level. The resulting charts in the 2013 excel software were drafted and compared.
    Results & Discussion
    There are several ways to improve the quality of meat and its better use in the production of meat products. One of these methods is to increase the solubility of the meat proteins and, consequently, to crumble and increase the properties of the emulsion and other functional properties such as increasing water holding capacity. Today the effects of the enzymes in plants, bacteria and fungi have been investigated. In this study, the Aspergillus Niger fungal enzyme was used to crust meat. One of the results of this study is that the fungal enzymes have been able to greatly increase the water content of the water, pH and soluble proteins in the flesh, due to increasing the duration of the enzyme's effect and the concentration of the enzyme on Insoluble proteins such as collagen and elastin are completely digestible and their nature has changed (Englund et al., 1968). Also, the results show that the enzyme breaks down some of the protein proteins and forms them in smaller molecular weight units. As you can see, increasing the amount of enzyme concentration on meat proteins has increased the amount of crust and solubility of meat proteins.
    Keywords: Aspergillus niger, Soluble protein, Meat tenderness, pH
  • Mahsan Irajifar, Mohammad Javad Varidi *, Mahdi Varidi, Younes Zahedi Pages 37-54
    Introduction
    Camel carcasses has lower fat content in comparison with cow, moreover, camel meat has relatively higher polyunsaturated fatty acids and lower cholesterol contents (Kadim et al., 2009a & 2006). However, calcium amount of camel meat is greater than that of cow, and its lower consumption is partly related to this issue. With increasing demand of camel meat, more attention has been paid to the quality and chemical composition of it. Acid marinade can be used through the diffusion of the solution and its propagation over time as an extensive method to improve the meat tenderness (Yusop et al., 2010). Lactic acid is often used in the meat industry as an antimicrobial during carcass slaughter. In addition, lactic acid can improve meat tenderness (Hinkle et al., 2010). The aim of the present study was to determine the influence of lactic acid and sodium chloride on textural and sensory properties, also and proteolysis pattern of biceps femoris muscle of camel.
    Materials and Methods
    Six 4 to 7 years old camels were transported to the slaughterhouse in Mashhad (Iran). Slaughtering and dressing of camels were carried out according to Islamic methods. All chemicals and reagents in the experiments were of analytical grade and purchased from Merck and Sigma-Aldrich companies. Biceps femoris muscle was used as an experimental material, cutting into 2×2×5 cm3 pieces, and laid in lactic acid solutions (0, 0.5, 1, and 1.5% v/v, all accompanied with 2% w/v NaCl) at a ratio of 1 to 4 (meat to marination solution) within plastic bags. Marination process was carried out for 0, 24, 48, 72 h at 4 °C. The meats were then removed from the marinade and dried lightly. After that, moisture, ash, protein and fat contents of the meat were specified by AOAC (2002). Shear force was measured by TA.XT plus texture analyzer (Stable Micro Systems, UK) provided with a Warner-Bratzler shear force blade method in order to evaluation of meat tenderness (Byrne et al., 2000). Myofibrillar fragmentation index (MFI) was determined as described by zahedi et al. (1393). Sarcomere length was measured with the method of Botha et al. (2007). One-dimensional gel electrophoresis was determined as described by zahedi et al. (1393). Collagen content was specified by AOAC (1993). Sensory properties including color, texture, flavor, juiciness and overall acceptance were performed using a 5-point structured hedonic scale (Hoffman et al., 2006 & 2008). One-way analysis of variance (ANOVA) was used to determine the significant differences between treatments using SPSS software (version 19). Duncan’s multiple range test was used to compare the means.
    Results and discussion
    Acid concentration and marination time had a significant effect (p <0.05) on sarcomere length. It was likely due to the fact that the addition of acid led to increase in pure positive charges on myofibrils and cytoskeletal proteins. As a result, more repulsive forces were generated between the protein molecules of myofibrils. Eventually, myofibrils swelling caused distancing Z lines from one another, and increasing the sarcomere length (Ke et al., 2008). The results of analysis of variance showed that the concentration of lactic acid had a significant effect on MFI (p<0.05), and MFI value was less than zero at 0% concentration, however, it was non-significant in relation to the time (p> 0.05). The higher MFI values of the marinated samples may be due to the proteolysis of myofibrile proteins using D-cathepsins which activated at acidic pH (range 3-6). Meat samples marinated in the highest concentration for 72 h showed the lowest WBSF (p<0.05). The tenderising mechanism of acid marinades was believed to be including weakening of structures due to swelling of meat, increasing proteolysis by cathepsins, and conversion of collagen to gelatin at low pH during cooking (Berge et al., 2001; Offer & Knight, 1988). The retention time and acid concentration did not have a significant effect (p> 0.05) on the collagen amount of lactic acid treated samples. It was likely that low acid concentration, although affecting some of the parameters, is not suitable for degradation of connective tissue (Hinkle et al., 2010). Sensory analysis showed that tenderness of the samples marinated at with 1.5% acid received the highest score (p<0.05), which was consistent with the instrumental results. Acid concentration significantly affected (p<0.05) total acceptance of the samples. Higher levels of acid can be used for marinating without adversely affecting the consumer acceptance. Results from SDS-PAGE showed that number of seven bands on gels, on average, were belonged to intact proteins, and other bands were considered as peptides which resulted from proteins proteolysis, especially heavy proteins. Also, time had non-significant effect on band area of myosin heavy chain (p>0.05), while, acid concentration had a significant effect on the area of ​​this protein (p<0.05). The band area of proteins C, α-actinin and actin proteins enhanced as a function of acid concentration and marination time (p<0.05).
    In conclusion, we can claim that lactic acid and sodium chloride can be used as an effective acidic marination to improve biceps femoris muscle of camel meat. This method can be advice as a trick for tenderizing camel meat in household consumptions, restaurants and also meat industry, thereby increasing demand for camel meat in order to gain further healthy benefits of it.
    Keywords: Lactic acid, biceps femoris, Camel
  • Maryam Zaeri, Simin Asadollahi *, Mahnaz Hashemiravan Pages 55-65
    Introduction
    Fat substitutes are the compounds that use for providing all or some fat properties, while producing fewer calories than it. It is noteworthy that in confectionary products, carbohydrate-based fat substitutes are more used than other substitutes because of having other technical and economic benefits and one of these substitutes is gum. In this regard, in the present research, the effects of locust bean gum and xanthan gum as a fat substitute on the physicochemical, rheological and sensory properties of oil cake were studied.
    Materials and Methods
    Treatments included: A0 (control), A1 (0.2% (w/w%) xanthan and 0% locust), A2 (0.4% (w/w%) xanthan and 0% locust), A3 (0.6% (w/w%) xanthan and 0% locust) B1 (0.2% (w/w%) locust and 0% Xanthan), B2 (0.4% (w/w%) locust and 0% Xanthan), B3 (0.6% (w/w%) locust and 0% Xanthan), C1 (0.1% (w/w%) locust and 0.2% xanthan), C2 (0.2% (w/w%) locust, and 0.2% xanthan), C3 (0.3% (w/w%) locust, and 0.3% xanthan), D1 (0.4% (w/w%) locust, and 0.2% xanthan) and D2 (0.2% (w/w%) locust and 0.4% xanthan). In order to produce an oil cake, in the first step, the eggs, the sugar and emulsifier in the formulation were completely mixed by mixer with high speed for 3 minutes. In the second step, the oil and water were added to the mixture and mixed by the mixer with high speed. In the third step, flour, vanilla, baking powder, invert syrup and salt were added and mixed for 3 minutes at medium speed. In the fourth step, the dough obtained from the previous stage was poured into the desired molds and cooked in an oven at 175 o C for 30 minutes. Finally, the cakes were packed in polyethylene bags and stored at room temperature. The tests performed on the dough included the density, viscosity and specific weight, as well as tests on the final product included the measurement of moisture, aw, volume, color, fat, height and sensory tests. On the other hand, to evaluate the effect of xanthan gum and locust gum on cake texture, the test of firmness was performed on days 1, 7 and 15. In order to analyze the data obtained from the experiment (except for the instrumental analysis of data on the staling conducted by using a factorial experiment in a completely randomized block design), a completely randomized design with three replications was used and the mean comparisons were conducted by Duncan's multiple range test, at the probability level of α=1% and by SPSS software version 16.
    Results and Discussion
    According to the results, adding gum at different levels increased the viscosity of the dough samples compared to the control. The reason for the results is that the reaction between the gums and the protein of flour, especially gluten, leads to the strength of the gluten network and the increase in viscosity of the dough. According to the results, with the addition of different levels of gum, the density of dough decreased, some reasons of which can be water absorption and the amount of air bubbles in the dough. According to the results, by increasing gum content, the moisture content of cake samples increased due to the presence of hydroxyl groups in these compounds that form a hydrogen bonding with water, resulting in the stability of the gluten dough network, better preservation of dough water, reduction of the staling and firmness of the product. Also, by increasing the amount of gum, the fat content of the samples decreased. The reason for decreasing the fat in the cake samples containing the gum was to use them in the formulation of produced cakes instead of oil. On the other hand, the height of the cake is directly related to the volume of the samples, so that the height of the cake samples will be decreased by decreasing the volume, which it is consistent with the results obtained in this study. According to the results obtained in this study, when the amount of gum used in the product structure increased, the amount of fat decreased, and gradually the height of the desired cakes also increased. Then, the volume of samples increased by increasing gum content. The reason for increasing in volume of the samples containing gum is increasing the viscosity of the dough, slowing down the gas release rate, maintaining it in the early stages of cooking, and thus retaining CO2 and water vapor in the air cells. According to the results, the addition of gum increased the L * color index compared to the control sample. The reason for the increase of L* color index in gum-based treatments can be attributed to the dark color of gums, and on the other hand, to the reaction of becoming brown in the formulation of cake production. Adding the different gum levels also decreased a* color index. This is due to the moisture content in the crust, the intensity of the Maillard reaction, and the amount of light and bright colored compounds in the cake. According to the results, adding different gum levels decreased the b* color index in the treatments containing it. Also, increasing the levels of xanthan and Locust gum consumption decreased the staling of samples. According to the results, the addition of gums to the treatments increased the sensory scores of flavor due to the presence of aldehyde compounds in xanthan and locust gums. Addition of Locust bean and xanthan gums also increased the sensory score of color. The reason for this result can be attributed to the Maillard reaction. Overall, the addition of different levels of gums increased the total acceptance score of samples compared to the control sample, which can be attributed to the presence of xanthan and locust gums which have the special and proper work properties. Finally, according to the results, D2 treatment was introduced as the best treatment.
    Keywords: Oil cake, Fat substitute, Locust bean gum, Xanthan gum
  • Sepideh Aryaee Majd, Mania Salehifar * Pages 67-76
    Introduction
    Donte is one of the most important fermented products in all over the world which similar to bread, after ferret fermentation process, dividing, shaping and rest of the dough, it would be frying in the oil instead of baking in the oven. We feel the need of using food additives (such as antioxidants, enzymes and etc.) in order to produce such high quality products with long shelf life because of industrialization of donut, large function production and increasing customer demand. The antioxidant compounds causes the food to have long-lasting shelf life and this results in producing a practical product. This research was carried out to evaluate effects of apple extract(in quantities of 8,10,12% ) and pimento extract (in quantities of % 5/1، 5/2، 5/3) as a rich source of Antioxidant affecting the rheological paste properties including the Farinography test, physicochemical properties such as hardness in periods of 1 to 3 days, humidity and color, shelf life index including peroxide in three periods of 1 , 15, and 30 days after cooking, DPPH and total Phenol inhibition tests and sensory evaluation of the product. Effects of the extracts on the rheological dough has shown that apple and pimento influencing the Farinography factors caused. Moreover none of these extracts had a meaningful effect on the index of paste quality. Result of phytochemical evaluation indicated that the hardness in two periods of 1 and 3, color value indicated, peroxide index and total acceptance decreased as the apple and pimento increased. The humidity content increased as the apple and pimento were used more. The result of DPPH and total Phenol inhibition tests showed that the pepper extract in DPPH free radical control was more successful than apple extract, and the amount of phenolic compounds in pepper extract was 2.4 more than apple extract. All experiments were replicated three times Optimized conditions included the use of 11.95% apple extract and 3. 3% sweet pepper extract in donut dough formulation. Generally addition of plant extracts can decrease oxidation speed of donut effectively.
    Materials and methods
    Include procedures and method of producing donut and methods of extracting apple and pimento also include test to measure flour such as moisture, ash, acidity, pH and protein and moisture, hardness, color, peroxide index, farinografy test, Total phenol and DPPH free radical inhibitory. The statistical population includes different levels of apple and pimento extracts, measured parameters have been studied by using simple line and polynomial equations 2 and 3.After testing in research methodology and data extraction, data analysis was carried out using RSM method and Design Expert 8 and statistical significance was set at (p<0.05) All results have been made 3 times, on average.
    Results & Discussion
    The effects of the extracts on the rheological dough has shown that apple and pimento influencing the Farinography factors caused an increase in water absorption, and pimento reduced the stability, development time and increased the degree of softening. Moreover none of these extracts had a meaningful effect on the index of paste quality. It should be mentioned that the aforementioned effects are more influenced by the apple extract Result of phytochemical evaluation indicated that the hardness in two periods of 1 and 3 decreased as the apple and pimento increased. The humidity content increased as the apple and pimento were used more. The result of low light color value indicated that L* decreased by increasing apple and pimento extracts, which this had no impact on a* and b* color indexes. The result of shelf life tests showed that by increasing the amount of apple and pimento extracts in donut samples in two periods of 5 and 30 days caused decrease peroxide index and The result of DPPH and total Phenol inhibition tests showed that the pepper extract in DPPH free radical control was more successful than apple extract, and the amount of phenolic compounds in pepper extract was 2.4 more than apple extract. The sensory evaluation results showed that the increase in apple and pimento caused reduction in total acceptance of the produced. All experiments were replicated three times Optimized conditions included the use of 11.95% apple extract and 3. 3% sweet pepper extract in donut dough formulation. Generally addition of plant extracts can decrease oxidation speed of donut effectively.
    Keywords: Donut, Pimento extract, Apple extract, Properties Physicochemical, Rheology
  • Peyvand Gholipour, Mohammad Fazel * Pages 77-89
    Introduction
    Ficus carica, commonly known as fig, is among the oldest types of fruit known to mankind. Drying is defined as a thermal process under controlled conditions in order to reduce the moisture in different types of food via evaporation. Edible films and coatings are used to enhance food quality by precluding oxidation and color changes in inappropriate conditions. Carboxymethyl cellulose (CMC) is thus widely used to improve food shelf life.
    Materials and methods
    All experiments were carried out on fresh edible green variety figs planted in the county of Neyriz Estahban. The figs were then immersed in the following solutions:Distilled water as a control variable without coating; carboxy methyl cellulose (CMC) solution 1% containing 0.25 gr/L glycerol; and CMC solution 1% containing 0.25 gr/L glycerol and 2% ascorbic acid. Preliminary tests including average diameter, pH, total flavonoids content, and antioxidant activity were performed on the figs. The fruits were dried using a device designed by the authors. At 60 ̊C, 70 ̊C, and 80 ̊C, the airflow in the device was 0.5 m/s, 1.0 m/s, and 1.5 m/s, respectively. After drying the samples, secondary experiments were performed which, in addition to the previous tests, included texture analysis, water reabsorption, volume measurement, shrinkage, and color analysis. A total of 27 treatments were applied in 3 rounds. A full factorial design was employed for statistical analyses while average values were compared via Duncan’s test at 5% significance. Calculations were performed using SPSS 16.0.
    Results & Discussion
    Using CMC coating, shrinkage increased compared to the control sample. As airflow accelerates from 0.5 m/s to 1.5 m/s, higher levels of shrinkage are observed. This could be attributed to the drier surface of the fruit caused by faster airflow. Shrinkage increases with the speed of airflow going from 0.5 m/s to 1.5 m/s. This is because at higher speeds, the sample is dried in a shorter period of time and sustains less damage.
    Water reabsorption was found to decrease with higher temperature and airflow. Weak reabsorption results from the breakdown of the internal structure of the fruits.
    CMC-ascorbic acid, CMC, and the control sample had the highest to lowest levels of firmness, respectively. The acid was found to preserve the internal cellular structure and preserve its breakdown. Moreover, firmness increases with the drying temperature.
    According to the results, the samples coated with CMC and CMC-ascorbic acid had lower pH compared to the control sample. Airflow speed and temperature are inversely and directly related to pH, respectively.
    In the CMC-ascorbic acid treatment, antioxidant capacity increased compared to the other two treatments. This may be associated with ascorbic acid’s higher ability to act as a carrier of anti-browning agents. Also, higher levels of antioxidant behavior were observed with higher temperature as it causes faster drying. Moreover, the coating acts to preserve the antioxidant and eliminates the impact of temperature.
    The highest amount of flavonoids was observed in the CMC-ascorbic acid treatment followed by the control sample and the CMC treatment. This is because the ascorbic acid serves to maintain the flavonoids in the samples. The flavonoid content increases with the airflow speed since the sample is dried in a shorter duration and the flavonoids are preserved. However, higher temperature reduces the flavonoid content since heat damages the pigment.
    The application of the CMC coating (alone or in combination with ascorbic acid) increased luminance compared to the control sample due to the preventative effect of the edible coating on the oxidation of the pigments in the fig samples. With faster airflows, surface moisture begins to vary which causes the coating to become lighter with higher L*. An increase in the temperature leads to lower L* as the heat causes the carotenoids and chlorophyll to break down and form brown pigments in the samples.
    Using the CMC-ascorbic acid coating increases a* in figs. Furthermore, as the temperature goes up from 60 ̊C, a* also increases.
    The coated samples demonstrate higher levels of b* compared to the control sample. In fact, the coating preserves the pigments and thus maintains the yellow color of the figs. The value of b* is directly related to the speed of the airflow because it decreases drying time. As a result, the product undergoes less heat. Finally, higher temperature leads to higher b* in the dried figs.
    Keywords: Fig, Edible coating, Carboxy methyl cellulose, Drying
  • Optimization of Ultrasound-assisted Extraction of Pectin from Tomato Pomace Using Response Surface Methodology
    Mahdi Zahedi, Zohreh Hamidi Esfahani, Hassan Ahmadi Gavlighi Pages 91-106
    Introduction
    Pectin is a structural heteropolysaccharide in the cell wall of plants and after extraction it is used as a gelling agent in food products. The main sources of pectin are apple and citrus peel, but pectin from various sources, may have unique properties. Therefore, research is ongoing to find new sources of pectin and study their properties. The conventional extracting method is performed using a solution of mineral acids, this process is time-consuming and has some disadvantages in terms of quantity and quality of extracted pectin. It is very important to look for new methods or modifications to produce pectin with high efficiency and quality. One of the new methods is ultrasonic extraction, which has been studied extensively. The aim of this study was to optimize and quantitative and qualitative evaluation of pectin extraction from tomato pomace as one of the major wastes of industries in Iran. Also Ultrasound was used as a new and effective method for extraction of pectin. Ultrasound assisted extraction (UAE) of pectin from waste tomato pomace was investigated and optimized using Box–Behnken response surface design. The individual and interactive effect of process variables (pH, temperature, extraction time and power density) on the pectin yield and purity was studied. Also, the degree of esterification, intrinsic viscosity and emulsifying properties were determined on optimized conditions.
    Materials and methods
    Tomato pomace was supplied from ATA Company located in Tehran, Iran. It was dried at 60 °C for 36 hours. Then was milled and sieved by 60 mesh size screen. Fatty acids and pigments were removed from tomato pomace and again dried. The obtained powder stored at ambient condition for further uses. Ultrasonic device (Ultrasonic Technology Development Company, IRAN and 400 w, 20 KHz) with 12 mm probe and double-shell tank was used to carry out the extraction. Response surface methodology (RSM) was carried out to study the effect of pH (1.5-2.5), temperature (60-90℃), extraction time (6-30 minutes), and power density (0.15-0.3 W/ml) as input variables on the yield and galacturonic acid (GalA) content as the output (responses). GalA content was determined by colorimetric method (titration), using the 3, 5- dimethylphenol as reagent and D-galacturonic acid as standard. To determine the degree of esterification, titration method was used. The intrinsic viscosity of pectin was determined by applying a capillary viscosimeter (Cannon Instruments Co., No. 150, Cannon-Fenske, Germany; k = 0.04137 mm2/s2). Emulsifying properties of pectin extracted at the optimal point were investigated at three levels of pectin concentration %0.25,% 0.5 and %1.
    Results and discussion
    The experimental data obtained were analyzed by analysis of variance (ANOVA) and second-order polynomial models were developed using multiple regression analysis both for pectin yield and GalA content. The models developed from the experimental design were predictive and good fit with the experimental data with high coefficient of determination (R2) value. Pectin yield and GalA content were more influenced by temperature. The highest extraction yield (10.5%) and galacturonic acid content (65%) was obtained at pH of 2, temperature of 86℃, time of 30 min, and power density of 0.3 W/ml, while in the conventional extraction method with the same extraction conditions, extraction yield of 4.5% and galactoronic acid content of 55% was obtained. According to results of this experiment, it can be concluded that main advantage of UAE is considerable shortening of extraction time with enhancement of pectin purity. Under optimal conditions, pectin with a degree of esterification 76% and intrinsic viscosity of 2.6 dl/g was obtained. The highest emulsifying activity (87.5%) was obtained at %1 concentration. By holding the emulsion at a temperature of 4°C and 23°C, the emulsion stability was significant (99%) at the concentration of %0.25 over a period of 30 days. These results showed that tomato pomace could be used as a good source of low cost pectin.
    Keywords: Pectin extraction, Tomato pomace, Ultrasound, Emulsifying activity
  • Nafiseh Ravatab, Simin Asadollahi *, Mohammad Reza Eshaghi Pages 107-120
    Introduction
    Chocolate is a complete and correct process of mixing one or more primary ingredients with the cocoa beans. These raw materials include the edible sweeteners or sugar, dry milk powder, edible essential oil and flavors as well as plant kernels. Despite high levels of fat and sugar, chocolate, has a significant contribution to human nutrition through the supply of antioxidants and polyphenols. It also has the beneficial minerals, especially potassium, magnesium, copper and iron. Milk chocolate is a complex rheological system that includes the solid phase (cocoa powder, sugar powder and no-fat dry milk powder) released in the continuous phase of cocoa butter. As mentioned, the chocolate contains three essential ingredients in foods, namely, protein, carbohydrate and fat, along with essential minerals that considering its physicochemical properties, the property of functionality can be activated in it by adding certain materials. The first member of omega-3 family is the alpha-linolenic acid that is not produced in the human body, hence it is called essential fatty acid and plays a very important role in many physiological responses of the human body and is considered as a necessity in the diet. The plant resources are healthier, cheaper, and more accessible. The highest amount of fatty acids, α-linolenic acid (short omega-3 chain), was found in plants. Among the plants, flaxseed has the highest fatty acid content (about 50%). Considering the above-mentioned cases, the possibility of producing the functional milk chocolate containing omega-3 fatty acid by this plant resource was investigated.
    Materials and Methods
    The treatments included control, L10, L20, L30 and L40 with the amounts of 0, 10, 20, 30 and 40% of flaxseed powder replacing butter, cocoa powder, dry milk and sugar. The experiments conducted included the study of physicochemical (sugar, fat, acidity, moisture content, peroxide, ash, particle size, texture and omega-3 levels) and sensory properties. In order to analyze the data of the research, a factorial experiment was used in a completely randomized design and the mean comparison was conducted by Duncan's multiple range test at the probability level of α =5%.
    Results & discussion
    The results obtained by studying the effect of adding flaxseed powder on the physicochemical properties, color, texture and sensory properties of functional milk chocolate showed that the addition of this material does not have a negative effect on the chemical properties of any treatment. The biggest concern was the oxidation of the oil in the flaxseed powder, which was solved with keeping conditions at 4 ° C and in none of the treatments the amount of peroxide did not increase more than the standard of chocolate (2%). On the other hand, the moisture content of the chocolate remained at the standard level due to the proper packaging and dry storage. Chocolate produced had a bitter taste in L30 and L40 treatments, despite having a good amount of sugar and dry milk powder, due to the relatively bitter taste of flaxseed oil and powder, but this bitterness was not so bad and unpleasant in L10 treatment. Chocolate acidity was not changed undesirably by adding flaxseed powder and replacing some of its oil with cocoa butter. Since the particle size of the flaxseed powder was more than that of cocoa powder and sugar, it reduced the volumetric surface, and fewer chemical bonds was formed between the hydrophilic and hydrophobic surfaces, resulting in less storage time of product at room temperature. Of course, this problem was less significant in L10 treatment, but in L30 and L40 treatments an inappropriate texture were found. The amount of omega-3 residues was zero in L10 and L20 treatments and was not detected by chromatography device, which indicated an inadequate ratio of antioxidant and flaxseed powder. However, since the maximum allowed antioxidants were used in chocolate, more amount of flaxseed should be used, so that as L30 and L40 treatment this fatty acid remains in the chocolate and does not oxidize. Also, by increasing the amount of flaxseed powder in treatments, viscosity also increased, due to the large size of particles and the lack of adequate bonding between hydrophilic and hydrophobic parts. Of course, this indicator was so high in L40 treatment that a problem was even created in molding. The texture analysis behavior of the chocolate indicated that the chocolate texture was loose in L40 treatment so that it lacked the value of production. The texture of this treatment was so loose that it became doughy at ambient temperature. In terms of sensory properties, a significant difference was found between the treatments and the control sample, indicating a decrease in the quality of chocolate produced. Overall, L40 treatment score was low due to so weak and doughy texture, inappropriate and bitter taste, the relatively dark color and the presence of many large pieces of flaxseed powder on chocolate. Therefore, its production does not seem logical, despite the proper amount of omega-3. L30 treatment had more desirable condition, but here, the texture was relatively loose too due to the presence of coarser flaxseeds. Of course, covering the bitter taste of flaxseed with sugar and dry milk powder and vanilla improved the opinion of the experts and increased their scores. It is noteworthy that the appearance and color of the product had better quality than L40 treatment. Regarding L10 and L20 treatments, although the scores of experts were better and they had better texture, color and flavor than two L30 and L40 treatments, but they did not have justifiable production due to the lack of remaining omega-3 in them that was the main purpose of this study. Totally, considering all properties, L30 treatment was introduced as the best treatment.
    Keywords: Milk Chocolate, Linseed powder, Omega-3, Physiochemical properties
  • Hanieh Arefi, Hojjat Karazhiyan * Pages 121-131
    Introduction
    Aerated dairy desserts have shown a great market potential as a function of consumer behavior, interested in lighter and healthier relish products. Mousse is an aerated dessert with stabilized foam structure that, although traditionally home-made, is nowadays produces on an industrial scale and is gaining space in the dessert market. The most popular mousse flavor is chocolate followed by orange, lemon and strawberry. The industrial production of aerated dairy dessert is delicate, requiring knowledge about the formation and stabilization of foam, the use of functional ingredients. Food foam is formed by air, liquid and surface-active agent such as proteins. The formation of air bubbles modifies the texture and the rheological properties of aerated food. In aerated confectionery, foams are produced by aeration of a mixture of sugar syrups and proteins. Egg white protein (EW) is the most widely used surface active agent for production of aerated dairy desserts. Foam is a two-phase system in which the diffused phase is air bubbles and the surface phase is formed by a thin layer of proteins with changed nature. These days, consumers prepare ready-made foods, and low-calorie, healthy foods and are more aware of the relationship between a diet and disease. Given the efforts to reduce the incidence of diseases such as cancer, cardiovascular diseases and health improvement, the expansion of plant-rich and anti-cancer foods can play a key role in ensuring health.
    Glycyrrhiza glabra (Licorice) is a perennial leguminous plant. The medicinal organ of the plant is constituted of its roots, containing triterpene saponins that has many indications. Licorice is one of the most important medicinal herbs in terms of economics that has been widely studied. The most striking compound of licorice is Glycyrrhizin, and this compound is responsible for licorice sweet flavor that is 50 times sweeter than sucrose. The aqueous extract (essential oil) of licorice root has a variety of applications in pharmacy and food industries due to its functional physical properties. Licorice root extract contain saponins which have surfactant properties. One distinctive property of saponins is that they yield relatively stable, soap-like foam in aqueous solution and can be used to adjust the foam in the food industries to improve the stability of the foam and create flavor and aroma. There is a growing commercial interest in using Liquorice root extract in food foams. However, little is known about the foaming behavior of the extract. Liquorice root extract can be used to modify food foams, to enhance foam stability. It can also be used in the development of new foamy foods.
    In general, the present study was carried out to develop a kind of mousse to which a native, local, natural plant ingredient was added and to verify the perspectives of the product with regard to potential for consumer health benefits and textural acceptance, and also to replace part of egg white with licorice as a plant alternative.
    Materials and method
    The ingredients in the preparation of Mousse are: egg white 15.67 g, sucrose 13.05 g, water 7.31 g, butter 5.57 g, cocoa 2.61 g, sugar powder 3.48 g, cream 52.33 g, vanilla 0.05 and various levels of licorice (12.5, 25, 37.5 and 50 percent), which replaced egg white in the above formulation.
    The samples' moisture content, overrun, volume of foam and density was measured. The texture analyzer was used to evaluate the textural attributes of the final product and TPA test was performed.
    Results and discussion
    The moisture content of samples reduced with increasing the substitution level. The moisture content of the product directly depends on the molecular weight, the type of hydrophobic and hydrophilic factors, and the number of these bonds. The most prominent compound of licorice is glycyrrhizin, a water soluble glycoside terpenoid that cannot be connected to a large amount of water. Therefore, it seems that reducing moisture content with increasing the replacement level is related to this characteristic of licorice.
    The highest amount of over run was quantitatively related to the control sample and the lowest amount was related to 50% licorice substitution level. Generally, overrun of samples decreased with increasing the amount of licorice replacement. The reason is the lack of the formation of a complex with Ovotransferrin (which is about 13% in egg white and helps formation of the foam) due to its denaturation. In conducted studies, it has been reported that with increasing the concentration of gum (gum in licorice), the volume of the foam system reduced.
    In fact, with increasing the viscosity of the aqueous phase by adding the gum, the air cannot enter the system during the stirring process, and therefore the volume of the system will be less increased. Albumin is a heterogeneous protein system that occurs during the foaming process of protein-protein interactions.
    Foam durability index of samples reduced with increasing the amount of the replacement of licorice. This is due to the fact that in low inter-surface tension, the surface covering film does not have sufficient strength, the two adjacent bubbles are easily deformed and undergoes considerable Van der Waals gravity. Thus, the bubbles mixed (coalescence) and the foam lost its stability. In general, licorice is less hydrophobic. This interacts with the formation of the coherent film on the air-water contact surface, which reduces the stability of the foam.
    Density of the foam samples increased with increasing the amount of licorice, the density of the foam is in fact a proportion of the diffused phase to the continuous phase and represents the amount of air entering it during the formation of the foam. In fact, the low density of the foam indicates a greater volume increase, and vice versa.
    The air phase of the foam samples reduced with increasing the amount of the replacement of licorice. The reason for this is that the use of the replacement of licorice reduced the ability of the foam due to reducing the elasticity of the interface of air bubbles and caused rapid degradation of the foam.
    According to the results obtained from the statistical analysis, it was found that with increasing the replacement of licorice in formulation, elasticity, chewing ability, cohesiveness, adhesive force, adhesiveness and the degree of softness increased. Therefore, using appropriate licorice concentrations, the amount of egg white consumption can be reduced to an acceptable level for mousse. In general, it can be said that using a low-cost source of a native, local, herbal plant, licorice in the formulation of an aerated dairy dessert we can produce a product without having a significant negative impact on the texture from the viewpoint of consumers.
    Keywords: Mousse, Egg White, Licorice, Textural attributes, physicochemical properties
  • Feresshteh Gholami, Sara Ansari * Pages 133-144
    Introduction
    Roasting is an essential process that improves the taste, color, texture and appearance of the product. The shelf-life is also extended as a result of roasting. The temperature and the duration of roasting are the most important factors that influence favorable traits. IR is a novel technique for roasting that, compared to conventional heating, has positive advantages such as shorten heating time, significant energy saving and uniform heating. This study aimed to investigate the effect of IR, compared to conventional, roasting on some physicochemical and quality properties of soybeans. Moreover, the conditions of roasting soybeans via the two mentioned methods were optimized using Response Surface Methodology (RSM).
    Material and methods
    Soybean seeds were collected from a commercial farm in Gorgan (North of Iran) and were dried in an oven at 40 °C for 48 hours until the moisture content became lower than 5 % w/w. For each treatment, 25 g of raw soybeans were spread in glass petri dishes and were then roasted under the conditions selected for each experiment. In conventional roasting an electrical oven with the temperature range of 180 to 260 °C and time duration of 5 to15 min was used. IR roasting was performed using an IR-warm air apparatus with a constant power of 1300 W at the air temperature of 180-240 °C for 5-15 min. After the temperature equilibrium was reached, the samples were packed in polyethylene bags and were kept at 4 °C until further analysis. For each roasting method, a central composite design consisted of two variables of time and temperature (each in three levels) and a total of 13 experiments were applied. Response surface analysis was performed using Design-Expert software. The moisture content of samples was determined by drying the samples in a drying oven at 105 °C until a constant weight was reached. The total phenol content was measured quantitatively by the Folin-Ciocalteu colorimetric method based on the reaction of reagents with the active hydroxyl groups of phenolic compounds. The radical scavenging activity of the samples was determined by the DPPH radical. The force needed to break the roasted seeds was evaluated using a texture analyzer equipped with a load cell of 25 Kg. The color of samples was evaluated in a special box under controlled conditions (in terms of light intensity and camera position) using a digital camera and the color parameters (L*, a* and b*) and the color change (ΔE) were determined.
    Results and Discussion
    According to the results, the second- and first-order models were suggested for the study of time and temperature effects on moisture reduction that were both significant (p<0.05). In two methods, total phenolic content and antioxidant activity models were significantly (p<0.05) second-order. With increasing time and temperature, these above values increased. Hardness and color differences of oven roasting were both first-order but only color differences were first-order for infrared roasting. Effects of two parameters were significant in all models. Optimum conditions for soybeans roasting sing oven and infrared were 223°C – 13 min and 231°C – 11 min, respectively. In optimum condition, experimental data for the moisture content, total phenolic content, antioxidant activity, hardness and color differences were: (1.10, 4.53, 42.75, 9.03, and 4.93) , (1.58, 4.93, 47.85, 6.20, and 4.79) respectively. Based on above results, infrared can be introduced as a replacement of conventional oven method for the roasting of soybeans.
    Keywords: Soybeans, Roasting, Infrared, Oven, Physicochemical properties
  • Abdol Majid Mirzaalian Dastjerdi *, Maryam Hashemi, Ahmad Shaker Ardakani, Seyed Hosein Mirdehghan Pages 145-157
    Introduction
    Pistachio is one of the dried and native products of Iran, which has a special economic and export significance due to its excellent quality. Pistachio kernel is rich in unsaturated fatty acids; therefore, its unsaturated fatty acids can tolerate oxidation and, as a result, change the flavor of the product. Various factors, such as temperature, relative humidity, light, etc., affect the storage of many nuts. During pistachio storage, the lowest rate of oxidation and hydrolysis occurs in low humidity and under the carbon dioxide atmospheric. Therefore, packaging with low-permeability plastic films, in a dry product with a moisture content of less than seven percent, can be a good way to maintain product quality. Pistachio packaging depends on several reasons include physical protection of the product, preventing product spoilage, attracting customers, preventing aflatoxin contamination, and ensuring a high-quality, healthy consumer product. Considering the high nutritional value of pistachios and its importance for exports, research is needed to improve the storage and the availability of a healthy, quality product. Therefore, in this research, the role of plastic coatings with different materials and layers on the shelf life and maintaining the nutritional value of dry pistachios was investigated.
    Materials and methods
    In this experiment, dry commercial Ahmad Aghaei pistachio cultivar was used. 200 grams of intact fruit was placed in plastic bags of different materials and then sealed with thermal sewing. Finally, the packages were placed at 20 ± 3 ° C. Polymeric coatings used include uncoated (control), single layer polyethylene plastics (PE), dual layer plastics with metallized polyamide composition, and extruded polyethylene (PA- ONM / PE ex), three layer plastics by combining polyester, polyurethane and polyethylene (PEs / Pu / PE), three layers of plastics with cast polypropylene, polyurethane and polyester composition (CPP / Pu / PEs), five layers plastics with polyamide, Ethylene vinyl Alcohol, two layers of extrusion and polyethylene plastics (PA / EVOH / Tie / Tie / PE), seven layers of plastics with polyethylene, two layers ethylene vinyl alcohol, two layers of extrusion bonded polymer, polyamide and extruded polyethylene (PE / EVOH / EVOH / Tie / Tie / PA / PE ex). The desired traits (weight loss, kernel hardness, peroxide value, free fatty acid, soluble sugars and sensory evaluation) was measured before the treatments and after 2, 4, 6, 8, 10 and 12 months of the storage period. The experiment was carried out in a factorial arrangement in a completely randomized design with three replications. Statistical analysis of the data was performed using SAS software version 9.1.3 and comparisons of the meanings by Duncan's multiple range test at a probability level of 1 percent. Drawing of the diagrams was done using Excel software.
    Results and discussion
    Pistachios packed with seven-layer and double-layered coatings showed the least weight loss and kernel hardness in the packaging due to the polymeric coating. Plastic coatings play an important role in preventing weight loss by creating a saturated micro-atmosphere around the fruit, and probably due to less moisture loss (less weight loss) in these packaging coatings, the hardness of the kernel was also lower than other materials. Also, during the storage period, the amount of peroxide value and free fatty acid in the control and the various types of packaging coatings increased, but this increase in the package with two and seven layers of slope was slower than the control and other materials. Double-layered and seven-layered treatments in comparison with control and other coatings had significantly lower peroxide value and free fatty acid content. In the tenth and twelfth months, the treat of (1.6) and seven layers (1.93) compared with control (10.4) and other coatings had significantly lower peroxide value. Also, at the end of the storage period (12 months), polyethylene (1.54), uncoated treatment (1.22) and tree layer packaging (CPP / PU / PEs (1.08) showed more free fatty acid content compared to other types of packaging. The most important degradation reaction that results in reduced product quality during the storage period is the radical oxidation mechanism and the formation of hydroperoxides. The main reason of kernel rancidity in nut packagings is inappropriate sewing of packages and the penetration of oxygen into the package. In the present study, two-layer and seven-layer packaging films showed less free fatty acid due to their low permeability to oxygen and moisture compared to other coatings. According to the results of other reports, it is likely that the higher peroxide value in unpackaged or packaged fruits in this study will be related to the presence of oxygen in the pack, which leads to an exacerbation of fat oxidation and the release of hydroperoxides. The influence of gases and light in the package, causing adverse changes in appearance and accelerating chemical reactions, as well as the presence of oxygen inside the package, also accelerates the oxidation reaction. Therefore, so the packaging type and the atmosphere inside it are two factors determining the shelf life of pistachios and the decrease score in texture, tastes, flavors of nuts during storage can be due to the absorption of moisture by nuts and the oxidation of fatty acids which affect the texture, taste and flavor. The coating used in this study showed better sensory parameters than the control.
    Keywords: Packaging, Ahmad Ahaghi dried pistachio, polymer coating, storage, quality
  • Neda Derakhshan, Ali Akbar Shokouhian *, Bahram Fathi Achachelooee Pages 159-170
    Introduction
    Peach fruit is considered to be a part of the fragrance fruits in terms of respiratory behavior, which is why it quickly becomes corrosive at normal temperature. Shelf life of peach is limited because of weight loss due to water loss and physiological abnormalities such as browning and tissue alteration. The Aloe Vera gel is a polyester coating and has an elastic property that is easily soluble in water and covers the entire area around the product to a similar extent. This gel acts as a protective layer on the product and protects the cells below the protective layer against mechanical damage and also prevents the loss of juices. Polyamines are a group of low-molecular-weight, naturally-occurring compounds with linear nitrogen groups found in almost all organisms and play a role in a wide range of physiological processes in plants, animals and microorganisms. The purpose of this experiment was to investigate the effect of Putrescine and Aloe Vera gel on the prolongation of the post-harvest life of peach fruit.
    Materials and methods
    Peach fruits (Prunus persica L.), the redtop cultivar at commercial maturing stage, when 80-50% of the fruits were painted, Harvested from the gardens of Moghan Agro Industry & Industry Co., located in Pars Abad city and after transferring to the laboratory, coating treatments as factorial based on completely randomized design with coating treatments in four levels of Putrescine (0, 2, 4, and 6 milli molar) and Aloe-vera gel treatments in four levels (0%, 15%, 30%, and 45%) in three time periods (15, 30 and 45 days) and three replicates with total of 144 experimental units was carried out. The fruits at -1° C and humidity of 95-90% were kept in cold storage. The pH of the juice were measured by a Digital pH Meter, soluble solids at room temperature was read by hand-made refractometer on a graded column. To measure total acid, titration was performed using 0.1% sodium hydroxide solution and the results were expressed in grams of malic acid in 100 grams of fresh weight. Measurement of vitamin C was done by titration with Decolor phenol Indole Phenol and Meta phosphoric acid and its amount expressed as mg of ascorbic acid in 100 grams of sample. The total phenol content was measured by the Folin- Sioculto method. The acetone method was used to measure carotenoid. Flavonoids were measured by acid ethanol method. The data of this study were analyzed using SPSS (9.1.3) and comparison of mean of treatments with LSD-test at probability level of 5%. Charts were also drawn using Microsoft Excel software.
    Results & Discussion
    Based on the analysis of variance table, the triple effects of Putrescine, aloe vera and time treatments in all indices had a significant effect at 1% probability level. Analysis of variance showed the lowest pH at combined treatment of 6 mM putrescine and 30% Aloe-vera gel. Also, the most titratable acidity was observed at combined treatment of 6 mM putrescine and 15% Aloe-vera gel and the most total soluble solids was observed at combined treatment of 2 mM and 45% Aloe-vera gel. Highest levels of vitamin C were observed at combined treatment of different levels of Aloe-vera gels at 6 mM putrescine. The most carotenoid levels was for combined treatment of 6 mM putrescine and 30% Aloe-vera gel and the most flavonoids was for combined treatments of 6 mM putrescine and 45% Aloe-vera gel. The pH peach juice increased during storage, due to the breakdown and decomposition of organic acids in the respiration process. The organic acids during storage are low due to their consumption during respiration and have a downward trend. The amount of soluble solids in fragrance fruits, such as peaches, increases during storage, when using putrescin significantly reduced the changes in soluble solids. The treatment of polyamide fruits slowly reduces the amount of total soluble solids that can be delayed in the production of ethylene and the ripening of fruit. It seems that the effect of polyamide treatments on their ability to maintain acidic conditions and the total acid content of the fruit extract, is related to their ability to compete with ethylene and delay in the ripening process. The amount of phenol over time has been increased. Phenol content of fruits and vegetables can be reduced or increased, which depends on storage conditions. With increasing maintenance period, the activity of PEL enzymes increases in different stages of harvesting, so that it has the highest amount at the time of commercial maturation. Based on the results of this study, it was observed that co-application of Putrescin coated treatments with aloe vera gel maintains biochemical parameters in terms of storage of peach fruit. Generally, the combination of 6 μM Putrescin and 30% Aloe Vera combination therapy had the best effect among other treatments in maintaining the traits in tomato fruit.
    Keywords: Acidity, Carotenoid, Flavonoid, Phenol, Post-harvest, protective layer
  • Fatemeh Sadat Mirza Khalili, Peyman Rajaei *, Mahnaz Hashemiravan Pages 171-180
    Introduction
    Today, the problem that the beverage industry faces and is largely unchanged, and may be added to its complexity day by day is to provide a healthy, durable, and acceptable product. One of the main steps in this regard can be replacing the preservatives and chemical additives with their natural varieties. Since Iran is very diverse and rich in vegetation, especially in medicinal plants, due to its special geographical conditions, and on the other hand, since the medicinal plants have the known antimicrobial and antioxidant properties, they can be used as a substitute for the chemical preservatives in the beverage industry. In this regard, the possibility of production of saffron gaseous beverage has been studied in this research.
    Materials and methods
    Initially, in order to produce the saffron gaseous beverages, the raw materials including saffron extract (Zardband Company), Sugar (Hedieh Company), Orang Serum Agar, Kant Agar Plate, Dichloran Rose-Bengal, Sodium Benzoate, Dipotassium Oxalate, Lead Acetate, Normal Sodium Hydroxide, activated carbon, citric acid, CO2 gas, ethyl alcohol, 70% ethanol and sodium hydroxide as well as materials used in the microbial tests including Lactobacillus agar medium (MRS Agar), Orange-Serum Agar, Dichloran Rose- Bengal (all from Merck, Germany) were prepared. Next, the treatments of research including T1 (65% sugar and 0.6% saffron), T2 (65% sugar and 4% saffron), T3 (65% sugar and 2% saffron), T4 (70% sugar and0.6% saffron), T5 (70% sugar and 4% saffron), T6 (70% sugar and 2% saffron), T7 (75% sugar and 0.6% saffron), T8 (75% Sugar and 4% saffron) and T9 (75% sugar and 2% saffron) were considered. In order to prepare the treatments, the syrup tanks were prepared. Usually, for each 7-unit syrup tank which is equal to 11.659 liters, 1,750 gallons of purified water were poured into the tank. The tank mixer was then turned on and the sugar was added according to the formulation of making the desired beverage to dissolve all the crystals of sugar in the water. Since the consumed sugar had foreign objects, the prepared syrup was not clear and clean, so it was completely transparent and clear by passing the material from special filters. In order to eliminate the pathogenic microorganisms, the syrup was pasteurized. After pasteurization, the syrup was directed to the steel tanks of the extract. The capacity of the extract tank was 10 units (17032.5 liters), 6 units (10219.5) and 4 units (6813 liters). Next, the extract was added at the same time as the syrup was added to the tanks. After mixing the concentrated extract and the syrup, the mixer was turned off and the mixture was placed in the same state for 15 minutes to remove its bubbles. It is recommended that the made extract will be kept in the tank for 24-12 hours in order to achieve better maturity. The prepared extract was directed by a transfer pump to a water and extract mixer (Intermix, Flumix or Perry Mix), to mix the water entered from the refinery with the ratio of 1 to 5 for the products with the brix less than 11 or with the ratio of 1 to 5.5 for the products with the brix below 10 and form the beverage drink. To improve the work efficiency and increase the quality of extract made, the solid materials such as citric acid and sodium benzoate were added to the syrup tanks by the additive tanks to allow the filtration. After the completion of each treatment, the samples were subjected to physicochemical, microbial and sensory tests. In the same regard, in order to analyze the data of research, a factorial experiment in a completely randomized block design was used. The mean comparison was performed by Duncan's multiple range test at the probability level of 1%=α and analyzed by SPSS software, version 16.
    Results and discussion
    According to the results, by adding sugar and saffron extract, the amount of brix was significantly increased and it seems the sucrose to be the main reason for the increase of brix because there is a direct relationship between the concentration of sucrose and brix. Also, by adding sugar and saffron extract to the beverages produced, the pH and acidity levels decreased and increased, respectively, but they were within the standard range. On the other hand, by adding sugar and saffron extract, the density of samples did not change significantly, but the amount of dry matter increased significantly, among which the increase in the amount of dry matter can be attributed to an increase in the sugar and saffron extract in the beverage. In this regard, the ash content of treatments and total sugar content of the samples were significantly increased due to increasing the amount of saffron extract and increasing the sugar content. According to the results obtained, the amount of mesophilic bacteria increased with the addition of sugars, but it remained within the standard range. Most of the mesophilic bacteria belonged to the sample containing 70% sugar. According to the results of sensory tests, the sweetness of beverage increased by increasing the sugar content, but in the samples in which the amount of saffron increased, the amount of sweetness showed no significant difference with the first sample. Since the saffron had a bitter and astringent taste, increasing the amount of sugar made the taste desired. On the other hand, as the amount of saffron increased, the color of samples was more attractive and their flavor was more favorable. In a general conclusion and based on the results of research, it was determined that it is possible to produce saffron gaseous beverage based on its chemical and medicinal properties, which could be an appropriate substitute compared to other beverages among which the treatment containing 75 % Sugar and 2% saffron extract was introduced as the most desired treatment.
    Keywords: Gaseous beverage, Saffron extract, Qualitative properties
  • Baharak Hassas, Leila Nateghi *, Alireza Shahab Lavasani Pages 181-198
    Introduction
    Jug cheese is a kind of hard cheese which traditionally produce from raw milk of cow, sheep and sometimes goat in west part of Iran. Its rippening period passed through the clay jug inside the soil, so it contains some varieties of microorganisms that provide it with specific and unique sensory properties. However, the transmission of some pathogenic bacteria in this product and its high fat content is very important in terms of general health.Therefore, the general objective(aim) of this study was to investigate the physicochemical, antimicrobial and sensory properties of low-fat jug cheese( produced produced from milk with 1.5% fat) Jug cheese containing Beta-Glucan powder ( 0. 25%, 0.5%, 1%) and menthe longifolia ethanolic extract (0.1, 0.2 and 0.3) and with compare the results with control cheese (produced from milk with 3% fat)during 60 days of ripening. Antibacterial results showed that properties using beta-glucan had no significant effect on the antimicrobial properties of the treatments and The use of ethanolic extract of mentha longifolia and increasing its concentration had significantly in the most extreme of the antimicrobial properties of treatments. According to results after 60 days of storage, the treatments containing 0.3% of Mentha longifolia extract, in comparison to the other treatments and Showed the most extreme decrease in the total count of microorganisms, lactobacillus, mould and yeast, coliforms, esherchia coli and staphylococcus aureus. The physicochemical properties investigation showed that the protein, fat, acidity and nitrogen soluble in water durin the preservation period have increased and pH, tissue hardness of the samples have significantly (p≤0.05) decreased. The results of sensory evaluation of cheese showed that the treatment which contained 0.5% beta-glucan and 0.3% ethanolic extract of mentha longifolia has the highest sensory properties. So using 0.5% beta-glucan and 0.3% ethanolic extract of menthe longifolia in low- fat cheese formulas can produce safe cheese with microbial and optimum texture at standard level.
    Materials and Method
    Jug cheese was produced from 1.5 fat cow milk obtained from Spoota Food Industries Complex, Urmia, Iran. First, milk was heated at 32-35ºC and cooled at 30ºC, then 0.06% cheese rennet (plant rennet, Cominux, Spain) was added and mixed for 5 minutes. After coagulation (45 min), the cheese was cut into 1*1*1 slices and wrapped in a cloth to be kept in room temperature for 12 hours under 0.1 weight plates for dewatering. Coagulants were impregnated in 3.5% salt solutions (since jug chesses is granular, there was no need to chop the samples). Therefore, the samples were squeezed into jugs and the jug was buried top-down in a 1-meter depth hole. Physicochemical, microbial and sensory properties of samples immediately after they were produced and on day 60 (1440 hours) were measured (Pakbin, 1391). Total protein was determined by macro-kjeldahl method with national standard No. 639. Soluble nitrogen was determined by kjeldahl method. Fat was determined by Gerber's method with national standard No. 366 (Anonymous, 1370). Level of moisture was determined by national standard No. 1753. pH was determined by a MA-Mettler pH-meter and titratable acidity (percentage of lactic acid) was determined by 0.1 normal and phenolphthalein as identifiers using national standard No. 2852 (Anonymous, 1385). Ash from cheese samples was measured by burning and full oxidation of food products in an oven at 550ºC (Khosroshahi, 1387). The Mohr titration method with national standard No. 1809 was used to measure salt in cheese samples (Anonymous, 1356). Tissue hardness (pressure or density) was measured using Universal Instron model 1140 and a probe at a constant speed of 100 mm/min. Compression test of cheese samples was done using a 36mm diameter cylindrical probe (hoseini et al, 1392). To measure number of living microorganism in jug cheese samples. To do so, 1g cheese was chopped with a sterile crucible or a mortar and mixed with 9cc buffered Peptone water. About 0.1cc of the solution was cultivated on a special medium by surface cultivation method. Number of microorganisms was measured by national standard No. 5484 in Kant Agar Plate mediums at 30ºC for 72 hours (Anonymous, 1381). Lactobacillus was measured in an MRS-Bile Agar medium (0.15% bile salt) with national standard No. 17164 at 37ºC for 72 hours (Anonymous, 1392). Molds and yeasts were measured, based on national standard No. 10154, in the YGC Agar medium for 5 days at 25ºC (Anonymous, 1386). To measure total formations, based on national standard No. 11166, a VRBA medium with two-layered pure palet method at 35ºC for 18-24 hours (Anonymous, 1387). E. coli was measured, with national standard No. 5234, in an EC Broth medium at 35ºC for 23 hours (Anonymous, 1394). Staphylococcus aureus was measured, based on national standard No. 6806-1, in a Bird-Parker medium with yolk and potassium tellurite at 37ºC for 48 hours (Anonymous, 1384). Sensory analysis was performed by 9 trained evaluators using a Five Point Hedonic Method with scales of one (very good), two (good), three (average), four (bad), and five (very bad) for taste, odor, tissue, and overall acceptability (Anonymous, 1387). In order to design the treatments, a completely randomized design with factorial arrangement was used. Treatments were designed with a control sample.To data analyze use Duncan one-way analysis of variance.
    Results & Discussion
    The results of antimicrobial evaluation showed treatments containing 0.3% ethanolic extract of mentha longifolia compared to other treatments showed the greatest reduction in total count of microorganisms, lactobacillus, mildew and yeast, coliforms, E. coli, Staphylococcus aureus. Thus, results of the study showed physicochemical characteristics the amount of protein, fat, acidity and nitrogen soluble in water increased and pH, moisture and texture hardness of samples significantly decreased (p≤0.05). The evaluation of sensory properties showed that treatment containing 0.5% β-glucan and 0.3% ethanolic extract of mentha longifolia had the highest sensory acceptability. Therefore, the use of 0.5% β-glucan with 0.3% ethanolic extract of mentha longifolia in the formulation of low-fat jug cheese, can be produced safe cheese with microbial and optimum texture at standard level.
    Keywords: Low-fat jug cheese, Beta- Glucan, ethanolic extract of Mentha longifolia
  • Mahsa Sadat Razavi, Abdollah Golmohammadi * Pages 199-210
    Introduction
    Considering the importance of appearance quality and effect of some factors such as area, perimeter, diameters, uniformity and defects on fruits, in grading, acceptability and final price, lead to measurement of some physical and mechanical properties of fruits. Pear fruit, belongs to Rosaceae family and Pomoideae sub-family, is one of the most important susceptible fruits in the world. Most of the pear fruits are originated of Pyrus Communis species. Iran, has degree thirteen of producing pear in the world. Dargazi pears, in Iran, are planted in north of Khorasan. By knowing the properties (physical and mechanical) of pear fruit, we can control probable damages that they undertake during harvesting, handling, packing, cooling, cleaning, sorting, storage, transporting and processing. Also, this knowledge will be useful in designing of harvesting machines and postharvest technologies. Until now, there has been no research in measuring physical and mechanical properties of Dargazi pear. So, the aim of this study was investigation of some physical properties including geometrical (length, mean diameter, radius of curvature), gravitical (mass, volume, ture density, bulk density) and mechanical properties (degree of elasticity, degree of plasticity, strain energy, resilience, hysteresis and hysteresis loss) of “Dargazi” pear.
    Materials and methods
    Pear fruits were hand-harvested from orchard, transported to laboratory and kept at temperature of 23˚C for further measurements. To determine mechanical properties, the Universal Test Machine (model STM 5) equipped with a 50 N load-cell (model DBBP-500, BONGSHINE, precision 2 kg) was used. The tests were performed on 75 pear samples divided to five groups for applying five force-level (40, 50, 60, 70 and 80 N) in form of uniaxial loading-unloading tests under constant speed of 10 mm/min. Samples were loaded between two solid steel plates (bottom plate was fixed). Three replications were considered for each force level. For measuring physical properties: mass, volume, dimensions; balance with 0.01 g precision, submerging method and digital caliper were used. To determine radius of curvature at three regions (crown, chick, calyx), image processing using a Canon camera model Powershot G10 and ImageJ software were used. To maintain uniform picture acquisition environmental conditions, samples were put in an isolated square wooden box, equipped by the camera at the top, three fluorescent lamps around the camera, and a hatch for putting samples in the box. The camera was connected to laptop using USB port to control image capturing. Images were obtained and processed in RGB color space. Drawing a circle from at least 3 points on the boundary line of interested region (curvatures at crown, chick and calyx) was used to determine radius of the circle and consequently, the radii of curvature at interested regions.
    Results and Discussion
    Analysis was performed using SPSS software. Mechanical properties were analyzed in form of completely randomized design. ANOVA, Duncan test and regression were used for understanding and explaining the relation between force and mechanical parameters. The results showed with increasing loading force, the values of loading energy (strain energy capacity), unloading energy (resilience), hysteresis (absorbed energy) and hysteresis loss will be increased. Also, with increasing degree of elasticity and radius of curvature at loading region (in otherwise, concentrated stress will be reduced because of minimized loading area), hysteresis and strain energy will be reduced, respectively. Resilience and force had high linear correlation with R2 = 0.992. Degree of elasticity and hysteresis can be used as indices for showing pear fruits susceptibility. Physical properties were analyzed using mean, maximum, minimum and standard deviation. The results of physical properties including mean length, mean diameter, mass, volume, true and bulk density, porosity and packaging coefficient are 84.162 mm, 73.729 mm, 188.8742 g, 185.4037 cm3, 1.01899 g/cm3 and 0.42759 g/cm3, 57.92009 and 0.42088, respectively. Also, the biggest and smallest radius of curvature were obtained at chick and calyx, 77.701 and 24.633 mm, respectively. The CV value of physical properties was less than 10 percent that shows the fruits uniformity. Dargazi pear has higher mean length, porosity and bulk density but smaller mean volume, mass and true density in comparison with Asian pear. Also, Dargazi pear has higher mean volume, porosity and true density but smaller mean length, mass and bulk density in comparison with Santa Maria pear. The applied image processing technique to determine the radius of curvature, has no limitation in measurement ranges, it’s possible to measure the biggest and smallest radii of curvature, also is nondestructive because of its non-contacting usage, so minimize possible damages.
    Keywords: Loading-Unloading, Strain Energy, Hysteresis Loss, Resilience, Degree of Elasticity
  • Kowsar Kakaei, Mohammad Noshad, Behzad Nasehi *, Mohammad Hojjati, Sharam Beiraghi, Toosi Pages 211-221
    Introduction
    In the past years, snack consuming in all age groups, special children have increased due to their low cost and eating readiness. Generally, these products have high starch content, but low nutrients such as vitamins, minerals, amino acids and fiber. In fact, most of the snacks are known as foods with high energy content and glycemic index, but low nutritional value. Adding fruits processing by-products to extruded snacks improves the nutritional value of snacks due to their high content of dietary fiber, bioactive compounds and minerals. Pomegranate (Punica granatum L.) is a perennial plant and is generally cultivated in tropical and subtropical regions the pomegranate seed is one of the pomegranate processing by-products including approximately 15-20% of total fruit. Pomegranate seed contains 36.5-42.4% fiber, 13.5-16.9% lipid, 8.5-11.3% protein and 24.09-33.41% carbohydrates. Therefore, pomegranate by-products rich in bioactive compounds and dietary fiber can be used as a functional ingredient. Since no research have been performed on using the pomegranate seed powder in making snacks yet, this research aimed to investigate the effect of pomegranate powders as a fiber supplement on the extruded physicochemical properties.
    Material and Methods
    The fruit of pomegranate were purchased from Khuzestan province in Iran. After peeling of pomegranate fruits, arils were pressed. The remaining pomaces were dried at 50 C for 48h. Dried pomace was powdered using a mixer grinder. The corn grits (Golden Corn Company, Iran) were prepared. The moisture and chemical component of raw materials were analyzed. The two screw extruders (model DS56, Jinan Saxin Company) was used to formulate and prepare snacks. First, response surface methodology (RSM) was used to optimize the amount of pomegranate powder to be added to the snacks. For this purpose, the influence of adding the pomegranate seed powder (0-20 %), extruder temperature (120-160 °C) and screw rotation speed (120-180 rpm) on the physicochemical properties of extruded samples were considered. For this reason, the moisture level of the input food was adjusted to 15 % and the feeding speed was 40 (kg/hr). The obtained results from optimization of the snacks formulation and process conditions shows that the optimum amount of factors are fallowing addition of fiber supplementary 11.8 %, the temperature of the extruder 160 °C, the screw speed of 147.1 rpm. After preparing optimal and control samples (without adding pomegranate powder), in order to evaluate the addition of pomegranate powder to the physicochemical properties of snacks, for this purpose, the effect of adding pomegranate powder on fat and protein content, total phenolic compounds, antioxidant activity, density, hardness, water and oil absorbance index, solubility index, soluble and in soluble fiber content, moisture content and microstructure of the produced snacks during 60 days of storage were investigated.
    Results and discussion
    By adding the pomegranate seed powder, the product moisture content decreased, which is probably due to high insoluble fiber content of pomegranate seed powder like apple residue. Moreover, by adding the pomegranate seed powder, the oil absorption index increased, which is probably due to presence of non-polar amino acids in the pomegranate seed powder. Existence of greater quantities of non-polar amino acids and presence of non-polar side chains in the extruded products may absorb oil hydrocarbon chains, leading to increase oil absorption index. Based on results, adding the pomegranate seed powder increases the hardness of the samples, which is probably due to the high amounts of oil and protein in the pomegranate seed powder. Researchers have reported that the use of food ingredients with high fat, protein, and fiber content increase the product tissue hardness. Also, the addition of pomegranate powder reduced water absorption of samples, which is probably due to the presence of insoluble water compounds such as fat and insoluble fibers in pomegranate powder and the reduction in the starch content of the samples due to the replacement of pomegranate powder. According to the results, addition of pomegranate powder increased the total phenol content and antioxidant properties of samples. While increasing the storage time, the total phenol content in the samples was reduced, which is probably due to the oxidation reactions that occur during storage. The results of this study showed that the addition of pomegranate powder increased the density, a * value, and nutritional value (such as iron, zinc, soluble and insoluble fiber, protein and fat content) in samples. While L* and b* values and water activity of the samples was reduced. Also, the addition of pomegranate powder decreased porosity and created heterogeneous and irregular cavities in the texture of snacks.
    Keywords: Shelf life, Extruded snacks, Pomegranate powder, Physicochemical properties
  • Mahsa Alikhani Faradonbeh, Reza Esmaeilzadeh Kenari *, Maryam Ghaderi Ghahfarokhi Pages 223-233
    Introduction
    The peel of fruits, in particular, are an abundant source of natural compounds and contain the higher amount of phenolics compared to the edible portions. Ultrasound-assisted extraction (UAE) is an ideal extraction method capable of producing high quantities of bioactive compounds with a shorter extraction time. Probe and bath systems are the two most common ways of applying ultrasound waves to the sample. Probe sonicators are constantly in contact with the sample and make reproducibility and repeatability difficult. In addition, the risk of sample contamination and foam production is higher. Bath sonicators can act on a range of samples simultaneously and allow for higher reproducibility. Kiwifruit belongs to family Actinidiaceae and genus Actinidia. Kiwifruit is characterized by a high content of vitamin C and other useful compounds such as vitamin E, flavonoids, and minerals. Phenolic compounds present in Kiwifruit peel are catechin, epicatechin, chlorogenic acid, caffeic acid, coumaric acid, and rutin. Several studies have been done on the extraction of various plants with ultrasonic waves. Most of the research on the extraction of plant extracts by ultrasound-assisted under various conditions of parentage such as time, solvent, temperature, and intensity of the sound obtained matched with other traditional methods of extraction and different studies have shown that there was never study on the effects of ultrasound bath and probes under the same conditions (temperature, solvent, time and frequency) on obtained extract and comparison of both two methods has been done. The aim of this study was comparing the antioxidant activity of Kiwifruit peel extract (KPE) obtained by two extraction methods ultrasound bath and probe techniques in same conditions temperature, solvent, time and frequency.
    Materials and Methods
    Hayward Kiwifruit variety was purchased from gardens in Tonekabon City. The peels were dried in the shadow at 25-27˚C, and then they were finely ground in a laboratory grinder. The dried peels were pulverized and sieved through a 40-mesh sieve to obtain the powdered samples. The dry plant material was then packed in the plastic bag and stored in a freezer at -18˚ C. 10 g of Kiwifruit peel powder was extracted with 100 mL of a mixture of ethanol–water 80% (v/v) at two methods Ultrasound Bath Extraction by using a 25 kHz ultrasonic system (model Elma Sonic S30H, Germany), temperature (45°C), time (20 min) and Ultrasound Probe Extraction by using a 25 kHz ultrasonic system (model VCX 250, Sonics & Materials, Inc., USA), temperature (45°C), time (20 min), amplitude of 45% with a probe of 1 cm in diameter was used. After obtaining extracts, an efficiency of extraction, total phenolic and flavonoid compounds, scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and ferric reducing antioxidant power (FRAP) assay were measured and concentration of 0.1 mg/ml of synthetic antioxidant TBHQ was as the control sample. All data were reported as mean ± standard deviation of three replicates. The results were compared by analysis of variance (ANOVA) using SPSS for Windows [version 16]. Mean differences were significant for extraction efficiency, total phenolic and flavonoid compounds based on T-test (binary comparison) and other tests based on Duncan's test at 0.05. Charts were drawn with Microsoft Excel version 2016.
    Discussion & Results
    These results showed that the highest amount of phenolic compounds, flavonoids, extraction efficiency, and antioxidant activity were obtained in UPAE-KP. In both extraction methods, with increasing KPE concentration, DPPH free radicals scavenging and ferric reducing antioxidant power also increased. The concentration of 2 mg/ml UPAE-KP extracted the highest percentage of inhibition (94.11%) in all of the concentrations of the extracts in two methods. UPAE-KP at concentrations of 1.5 and 2 mg/ml and UBAE-KP at a concentration of 2 mg/ml showed better performance in scavenging free radicals than TBHQ. Among the extracts, IC50 UPAE-KP was 0.2±0.06 mg/ml which was significantly different from UBAE-KP (P<0.05). TBHQ at a concentration of 0.1 mg/ml (with a percentage of inhibition of 88.04±0.5) showed a better radical inhibitory activity than the low concentrations of Kiwifruit Peel extracts. UPAE-KP with a lower IC50 (0.09±0.07) showed more reducing antioxidant power than UBAE-KP. TBHQ at a concentration of 0.1 mg/ml (with an absorption rate of 304/1) had greater reducing antioxidant power than the Kiwifruit Peel extracts at all concentrations except the concentration of 2 mg/ml UPAE-KP. In this study, the extraction of KPE with both ultrasound methods was acceptable in terms of efficiency and antioxidant activity, with the difference that the probe superior to the ultrasound bath. Therefore, according to the results, KPE was competitive with TBHQ activity. KPE can be used as a useful source to provide natural antioxidant, and the probe compared with the ultrasound bath is a better way of extracting the KPE phenolic compounds.
    Keywords: Kiwifruit Peel, Ultrasound, Antioxidant activity, Phenolic compounds