فهرست مطالب

پژوهش های صنایع غذایی - سال سی و سوم شماره 1 (بهار 1402)

فصلنامه پژوهش های صنایع غذایی
سال سی و سوم شماره 1 (بهار 1402)

  • تاریخ انتشار: 1402/01/14
  • تعداد عناوین: 10
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  • لیلا ناطقی*، پیمان رجایی، علیرضا ملکی کهکی صفحات 1-15
    زمینه مطالعاتی

     میوه انار(گلنار فارسی) یکی از مهمترین محصولات کشاورزی و گیاهان دارویی به علت وجود تانن و ترکیبات پلی فنولیک، خواص آنتی اکسیدانی و ضد میکروبی در درمان بیماری ها و به عنوان نگهدارنده طبیعی بکار می رود. هدف کلی از این تحقیق بررسی تاثیر سه متغیر نوع حلال، زمان و دما بر میزان استخراج فلاوونوییدها، IC50 و آنتوسیانین ها و اثر ضد میکروبی عصاره بهینه استخراج شده به روش خیساندن از گلنار فارسی بود.

    روش کار

    بدین منظور اثر نوع حلال (آب و متانول 80 %)، زمان (12، 30 و48 ساعت) و دما (20، 35 و 50 درجه سانتی گراد) بر مقدار ترکیبات زیست فعال و خواص ضدمیکروبی گلنار فارسی مورد بررسی قرار گرفت. 18 تیمار مطابق با روش سطح پاسخ باکس بنکن طراحی شد.

    نتایج

    بهینه سازی همزمان شرایط استخراج عصاره از گلنار فارسی با هدف دستیابی به بالاترین میزان ترکیبات فلاونوییدی، آنتوسیانینی و خواص آنتی اکسیدانی، با 614/95 % مطلوبیت در شرایط زمان استخراج 48 ساعت، دما C°50 و استفاده از حلال متانول پیش بینی شد. در شرایط مذکور میزان فلاونویید mg/g 6216/8، میزان آنتوسیانین µmol/g 7365/5 و میزان (mg/ml)IC50، 2793/7 بود. بالاترین مقدار میانگین حداقل غلظت مهارکنندگی (MIC) و حداقل غلظت کشندگی(MBC) عصاره گلنار فارسی استخراج شده در شرایط بهینه بر علیه باکتریهای استافیلوکوکوس اوریوس، اشرشیاکلای و کلستریدیوم پریفرانژنز به ترتیب 5/468 و 1875 µg/ml ، 5/937 و 3750 µg/ml، 5/937 و 5000 µg/ml بود. تیمار بهینه به روش خیساندن اثر ضد میکروبی بیشتری علیه باکتری استافیلوکوکوس اوریوس با بیشترین قطر هاله ی عدم رشد (mm13) در مقایسه با اشرشیاکلای وکلستریدیوم پریفرانژنز داشت.

    نتیجه گیری نهایی

    نتایج حاصل از این تحقیق نشان داد با بهینه سازی شرایط استخراج می توان میزان قابل توجهی از ترکیبات ضد میکروبی و آنتی اکسیدانی از گیاه گلنار فارسی استخراج نمود و از آن در صنایع غذایی و داروسازی استفاده نمود.

    کلیدواژگان: آنتوسیانین، آنتی اکسیدان، خیساندن، فلاونوئید، گلنار فارسی
  • مینا سیف زاده* صفحات 17-32
    زمینه مطالعاتی

     سس میگو فرآورده تخمیری است که به عنوان چاشنی غذایی در کشورهای آسیای جنوب شرقی استفاده می شود. در حال حاضر مهمترین روش فرآوری میگو تولید فرآورده های منجمد می باشد. به طوری که میگوی منجمد 65 درصد صادرات را شامل می شود. تحقیق حاضر با هدف تهیه سس از میگوی ژاپنی تازه تالاب انزلی، بررسی کیفیت و زمان ماندگاری آن در یخچال انجام شد.

    روش کار

    برای این تحقیق 4 تیمار شامل میگوی تازه عمل آوری شده با سوربیتول، برنج پخته و سوکرالوز در نظر گرفته شد. میگوی عمل آوری شده بانضمام نمک به عنوان نمونه شاهد بود. به همه تیمارها به نسبت 1:1 نمک، اسید استیک، منو سدیم گلوتامات و سوربات پتاسیم افزوده شد. تیمارهای آزمایشی و شاهد به مدت شش ماه در دمای یخچال نگهداری شدند.

    نتایج

    در تیمارهای آزمایشی و شاهد فاکتورهای شیمیایی، میکروبی و حسی طی مدت زمان نگهداری تغییرات معنی دار نشان دادند (05/0>p). باکتری های کلی فرم، اشریشیاکلی، استافیلوکوکوس و سودوموناس و کپک و مخمر در تیمارهای آزمایشی و شاهد مشاهده نشدند. ویژگی های حسی در تیمار برنج پخته در مقایسه با سایر تیمارها افزایش نشان دادند (05/0p>). ارزش غذایی و جذب نمک بین تیمارهای آزمایشی وشاهد تفاوت معنی دار نشان ندادند (05/0p>). تیمار سوربیتول در مقایسه با سایر تیمارها رطوبت و تازگی بیشتری داشت (05/0p>). مقدار سس در تیمار برنج پخته و سوربیتول در مقایسه با سایر تیمارها به ترتیب افزایش و کاهش معنی دار نشان دادند (05/0>p). تیمارهای شاهد و آزمایشی تا پایان زمان ماندگاری در یخچال از کیفیت مطلوبی برخوردار بودند.

    نتیجه گیری نهایی

    هر چند که سس تهیه شده از سوربیتول در مقایسه با سایر تیمارها از تازگی بیشتری برخوردار بود، اما با در نظر گرفتن این که طعم و مزه در تیمارتهیه شده از برنج پخته در مقایسه با سایر تیمارها بهترارزیابی گردید، پذیرش کلی و حجم سس تولید شده در این تیمار استفاده از برنج پخته برای تهیه سس از میگوی تازه قابل پیشنهاد است.

    کلیدواژگان: تالاب انزلی، زمان ماندگاری، سس میگو، کیفیت میکروبی، میگوی نیپوننس
  • محمدرضا مهربد، محمد حجتی*، حمید عزت پناه صفحات 33-48
    زمینه مطالعاتی

     دانه قهوه خام عطر و طعم ضعیفی دارد و قبل از مصرف باید بو داده شود.

    هدف

    از مایکروویو (650، 750 و 900 وات به مدت 5/1 دقیقه) و هوای داغ آون (C° 220 و 15 دقیقه) جهت بودادن دانه قهوه سبز استفاده شد.

    روش کار

    دانه قهوه سبز با آون و توانهای مختلف مایکروویو بو داده شد و ویژگی های فیزیکوشیمیایی (رطوبت، سختی بافت، رنگ، فعالیت آنتی اکسیدانی و ترکیبات فرار) و حسی نمونه ها در قالب آزمایش فاکتوریل با طرح پایه بلوک های کامل تصادفی بررسی شدند.

    نتایج

    میزان رطوبت، سختی، روشنایی و فعالیت آنتی اکسیدانی دانه های قهوه در اثر بودادن کاهش معنی داری یافت در حالیکه بودادن موجب افزایش شدت قرمزی و زردی دانه های قهوه شد. نمونه های تیمار شده با مایکروویو میزان سختی کمتر و فعالیت آنتی اکسیدانی بیشتری نسبت به نمونه های بوداده شده با آون داشتند. بودادن کاهش مقدار ترکیبات اسیدی را درپی داشت ولی مقادیر ترکیبات الکلی، کتونی، آلدهیدی، فورانی، پیرازینی و فنولیک در قهوه های تیمار شده افزایش معنی داری یافت. بیشترین و کمترین میزان ترکیبات فرار به ترتیب در قهوه تیمار شده با مایکرویو در توانهای 650 و 900 وات مشاهده شد. بودادن منجر به افزایش مقبولیت رنگ ظاهری قهوه شد. قهوه بو داده شده توسط مایکروویو با توان 650 وات به طور معنی داری نسبت به سایر نمونه ها از ویژگی های حسی بالایی برخوردار بود.

    نتیجه گیری نهایی

    مایکروویو با توان 650 وات با ایجاد ترکیبات معطر بیشتر در دانه های قهوه، پذیرش حسی بهتر و فعالیت آنتی اکسیدانی بیشتر می تواند روش مناسبی برای بودادن دانه های قهوه باشد.

    کلیدواژگان: قهوه، بودادن، فعالیت آنتی اکسیدانی، گازکروماتوگرافی، ترکیبات فرار
  • سعید خانزادی*، عباس مهرایی، محمد هاشمی، محمد عزیززاده صفحات 49-67
    زمینه مطالعاتی

     بهینه یابی پوشش نانوامولسیون کیتوزان حاوی اسانس زوفا باعث بهبود عملکرد این گروه از پوشش ها می گردد.

    هدف

    در این مطالعه اثرات پوشش نانوامولسیون کیتوزان حاوی اسانس زوفا روی پدیده ی ملانوزیس و ارزیابی رنگ قطعات میگو طی 12 روز در 4 درجه سانتی گراد بررسی شد.

    روش کار

    ابتدا اسانس زوفا به روش تقطیر با آب استخراج شد؛ اجزای تشکیل دهنده اسانس به وسیله GC/MS شناسایی شد. بیشترین ترکیبات آن شامل ایزوپینوکامفن (%45/35)، پینوکامفن (%81/11) و بتا-پاینن (%12/10) می باشد. این مطالعه شامل دو مرحله ی تهیه ی پوشش و مدل سازی غذایی می باشد. پس از تهیه ی نانوامولسیون کیتوزان حاوی اسانس، پارتیکل سایز و PDI تعیین شد. سپس نمونه ها در 10 تیمار آماده و برای ارزیابی رنگ و تعیین میزان ملانوزیس آنالیز شدند.

    نتایج

    در روز 12 کمترین میزان قرمزی و زردی در گروه های نانوامولسیون کیتوزان حاوی اسانس زوفا (1% و %5/0) در مقایسه با گروه کنترل مشاهده شد. میزان روشنایی نمونه ها با افزایش زمان نگهداری در تمامی تیمار ها کاهش یافت؛ یکی از دلایل این کاهش به دلیل ظهور لکه های سیاه است. تیمار نانوامولسیون کیتوزان حاوی زوفا %1، بالاترین امتیاز و تیمار های کنترل، کیتوزان و کیتوزان سونیکیت شده پایین ترین امتیاز را به لحاظ ملانوزیس تا انتهای دوره در مقایسه با کنترل داشتند.

    نتیجه گیری

    بر اساس نتایج این مطالعه پوشش نانوامولسیون کیتوزان حاوی اسانس زوفا می تواند باعث حفظ شاخص رنگ در گوشت میگو در مقایسه با گروه کنترل شود و رنگ آن را بهبود بخشد و به عنوان یک ترکیب ضد ملانوزیس جایگزین ترکیبات سنتزی مانند متا بی سولفیت سدیم شود.

    کلیدواژگان: کیتوزان، نانوامولسیون، اسانس زوفا، ملانوزیس، لکه ی سیاه
  • معصومه آقازاده*، جعفر نظرزاده، قاسم دبیری صفحات 69-81
    زمینه مطالعاتی

     اکسایش روغن باعث تغییر خصوصیات ارگانولپتیکی، کاهش ارزش غذایی و عمر نگهداری آن می‏شود و به دلیل تولید ترکیبات نامطلوب در روغن برای سلامتی مصرف کنندگان نامطلوب است. با توجه به عوارض ناشی از مصرف آنتی اکسیدان های سنتزی، تاکنون تلاش های فراوانی در زمینه شناسایی و استخراج ترکیبات آنتی اکسیدانی از منابع گیاهی به منظور استفاده در مواد غذایی و داروسازی به عنوان جایگزین انواع سنتزی صورت گرفته است. یکی از گیاهانی که امکان بررسی و مطالعه بیشتر ازنظر فعالیت آنتی اکسیدانی و میزان ترکیبات فنولی و فلاونوییدی برای آن وجود دارد گیاه پونه (Mentha Pulegium L.) است.

    هدف

    هدف از این پژوهش بررسی خاصیت آنتی اکسیدانی اسانس پونه در روغن بزرک، به منظور انتخاب یک جایگزین مناسب به جای آنتی اکسیدآن های سنتزی مانند ترسیو-بوتیل هیدروکینون(TBHQ) ، هست.

    روش کار

    در این پژوهش اسانس پونه به وسیله کلونجر (تقطیر با بخارآب) استخراج شده و در چهار سطح غلظت (05/0، 1/0، 2/0 و 3/0 درصد) (وزنی/وزنی) در به تاخیر انداختن اکسایش در روغن بزرک، با اثر آنتی اکسیدان سنتزی TBHQ در سطح غلظت 02/0 درصد از طریق محاسبه عدد اسیدی و عددپراکسید در طول فواصل زمانی (صفر، 7، 14، 21 و 28) روز، مورد مقایسه قرار گرفتند.

    نتایج

    نتایج حاکی از این است که بیشترین مقدار عدد پراکسید برابر 17/8 (میلی‏اکی‏والان/کیلوگرم) مربوط به نمونه شاهد در روز 28 و کمترین مقدار پراکسید برابر 83/3 (میلی‏اکی‏والان/کیلوگرم) مربوط به تیمار حاوی TBHQ در روز هفتم حاصل شد. همچنین بیشترین مقدار عدد اسیدی برابر62/2 (میلی‏گرم پتاس/گرم) مربوط به نمونه شاهد در روز 28 و کمترین مقدار عدد اسیدی برابر 88/1 (میلی‏گرم پتاس/گرم) مربوط به تیمار TBHQ در روز اول حاصل شده است.

    نتیجه‏ گیری نهایی

    با توجه به نتایج به دست آمده از هر دو آزمون عدد اسیدی و عدد پراکسید، اسانس پونه در غلظت های بالا اثر آنتی اکسیدانی قابل مقایسه ای با تیمار حاوی TBHQ نشان داد و می توان به عنوان جایگزین مناسبی برای آنتی اکسیدان های سنتزی محسوب شود.

    کلیدواژگان: اسانس، خاصیت آنتی‏ اکسیدانی، گیاه پونه، روغن بزرک، ترسیو-بوتیل هیدروکینون(TBHQ)
  • پروا عبدالهی، رضا اسماعیل زاده کناری*، رضا فرهمندفر، مریم عزیزخانی صفحات 83-96
    هدف

    هدف از این مطالعه بررسی اثر عصاره کاروتنوییدی استخراج شده با غلظت 200 پی پی ام از کینوای قرمز با روش سیال فوق بحرانی با کمک حلال اتانول10%، 15% در مقایسه با بتاکاروتن تجاری جهت پایدارسازی اکسایشی روغن سویا بود. روش کار: بدین منظور عصاره کاروتنوییدی از کینوای قرمز با روش سیال فوق بحرانی با کمک حلال های 10%، 15% اتانول استخراج شد و سپس همراه با بتاکاروتن تجاری با غلظت 200 پی پی ام به روغن سویا اضافه شد. نمونه ها به مدت 8 روز در دمای °C60 نگهداری شدند. آزمون های عدد پراکسید، عدد دی ان مزدوج و عدد تیوباربیتوریک اسید جهت بررسی تاثیر عصاره کاروتنوییدی و بتاکاروتن تجاری بر پایدارسازی روغن سویا اندازه گیری شدند.

    نتایج

    نتایج نشان داد که نمونه های حاوی عصاره کاروتنوییدی استخراج شده با سیال فوق بحرانی با کمک حلال های 10%، 15% اتانول در اکثر روز های نگهداری میزان پراکسید کمتری نسبت به نمونه های حاوی بتاکاروتن تجاری داشتند. کمترین میزان پراکسید در آخرین روز نگهداری با مقدار 21/7 میلی اکی والان بر کیلوگرم روغن مربوط به نمونه حاوی عصاره کاروتنوییدی استخراج شده با سیال فوق بحرانی با حلال 15% اتانول بود. نمونه های روغن سویا حاوی عصاره کاروتنوییدی در اکثر روزهای نگهداری به ویژه در آخرین روزهای نگهداری در مقایسه با نمونه های حاوی بتاکاروتن تجاری میزان دی ان مزدوج کمتری را نشان دادند و همچنین درکل روزهای نگهداری میزان تیوبار بیتوریک اسید کمتری داشتند.

    نتیجه گیری نهایی

    عصاره کاروتنویید استخراج شده با روش سیال فوق بحرانی در پایدارسازی اکسیداتیو روغن سویا نسبت به بتاکاروتن تجاری موثرتر بود.

    کلیدواژگان: پایداری اکسایشی، روغن سویا، سیال فوق بحرانی، عصاره کاروتنوئیدی کینوا، فعایت آنتی اکسیدانی
  • مریم جعفری*، زهرا اسیوند، سارا امیری سامانی صفحات 97-110

    در طی سال های اخیر تحقیقات بسیاری جهت یافتن منابع جدید هیدروکلوییدی به خصوص از منابع گیاهی بومی و بررسی خواص عملکردی آن ها انجام شده است و استخراج هیدروکلوییدها از منابع گیاهی جدید و مورد توجه زیادی قرار گرفته است.

    هدف

    گزنه رومی (Urtica pilulifera) از دیرباز در طب سنتی استفاده های فراوان دارویی داشته و دانه های این گیاه نیز می تواند منبع بالقوه ای برای استخراج موسیلاژ باشد. در تحقیق حاضر، بهینه سازی شرایط استخراج موسیلاژ دانه های این گیاه مورد بررسی قرار گرفته است.

    روش کار

    در این تحقیق با روش سطح پاسخ، تاثیر چهار متغیر مستقل در سه سطح شامل نسبت دانه به آب (1:5، 5/17: 1، 1:30)، دما (30، 5/57، 85 درجه سانتی گراد)، زمان (30، 135، 240 دقیقه) و pH (3، 5/6، 10) بر راندمان استخراج، محتوای پروتیین، پایداری امولسیون و شاخص های رنگ (L*، a* و b*) موسیلاژ دانه مورد بررسی قرار گرفت.

    نتایج

    افزایش دما (تا حد مشخص) و نسبت آب به دانه و pH بر افزایش راندمان استخراج موسیلاژ تاثیر معناداری (05/0>p) داشتند. در pHهای بالاتر، زمان کوتاه تر و مقادیر کمتر آب، محتوای پروتیینی موسیلاژ کمتر بود. موسیلاژ استخراج شده در pHهای پایین تر و مقادیر کمتر آب، تاثیر بیشتری در پایداری امولسیون نشان داد. بر اساس نتایج، فقط متغیر pH بر شاخص های رنگ تاثیرگذار بوده و با افزایش pH به ترتیب کاهش و افزایش معنی دار در شاخص روشنایی و قرمزی مشاهده شد.

    نتیجه گیری نهایی

    پس از بهینه سازی عددی، شرایط بهینه استخراج به صورتpH برابر با 23/4، زمان استخراج 9/239 دقیقه، دمای استخراج 79/45 درجه سانتی گراد و نسبت آب 5 برابر دانه تعیین شد. در شرایط بهینه بازده استخراج 08/11 درصد، محتوای پروتیینی 55/14 درصد، بیشترین پایداری امولسیون 50 درصد، شاخص L* 59/47 و شاخصa* 05/15 محاسبه شد که مطابقت خوبی با مقادیر پیش بینی شده داشت.

    کلیدواژگان: استخراج موسیلاژ، بهینه سازی، پایداری امولسیون، گزنه رومی
  • حسن محرم پور*، اکرم پزشکی نجف آبادی صفحات 111-127
    زمینه مطالعاتی

     افزودن باکتری های پروبیوتیک می تواند منجر به بهبود کارایی بیشتر باکتری های روده ای شود.

    هدف

    هدف از این مطالعه تولید شکلات پروبیوتیک و شکلات پروبیوتیک ریزپوشانی شده، بررسی و مقایسه خصوصیات شیمیایی، میکروبی و حسی آنها می باشد.

    روش کار

    در این تحقیق باکتری پروبیوتیک بیفیدوباکتریوم بیفیدوم با استفاده از آلژینات سدیم و کنسانتره پروتیین آب پنیر ریزپوشانی شده و سپس شکلات پروبیوتیک با افزودن گونه پروبیوتیک مذکور در مرحله قبل از تمپرینگ تولید گردید . تاثیر ناشی از ریزپوشانی روی زنده مانی، pH، اسیدیته، مقدار رطوبت، سختی، فعالیت آبی، ویسکوزیته، تنش تسلیم و ویژگیهای حسی شکلات، در طول 60 روز نگهداری در دمای C ° 22در مقایسه با نمونه شکلات حاوی باکتری پروبیوتیک ریزپوشانی نشده و شکلات معمولی(نمونه شاهد) ارزیابی شد.

    نتایج

    بررسی روند اسیدی شدن نشان داد که بیفیدوباکتریوم بیفیدوم ریزپوشانی شده و نشده تفاوت معنی داری ندارند ضمن اینکه تغییرات pH نیز بسیار ناچیز است. مقایسه دو نوع شکلات پروبیوتیک ریزپوشانی شده و نشده بیانگر وجود تفاوت معنی دار در فعالیت آبی، مقدار رطوبت، تنش تسلیم، ویسکوزیته و سختی بود. همچنین افزودن پروبیوتیکها در حالت آزاد و ریزپوشانی شده، تاثیر معنی داری روی بافت، رنگ، طعم، تردی و احساس دهانی نداشت. تفاوت زنده مانی باکتریایی محصول حاوی بیفیدوباکتریوم بیفیدوم ریزپوشانی شده در مقایسه با نوع آزاد بسیار ناچیز بود. نتایج ارزیابی زنده مانی در طی 20 روز نگهداری و در دمای 22 درجه سانتیگراد بیانگر آن بود که کاهش در تعداد باکتریهای بیفیدوباکتریوم بیفیدوم رخ داده است ولی شمارش آنها همچنان در محدوده تعریف شده برای فراورده های پروبیوتیک (106 تا 107 سلول زنده در هر گرم) است.

    نتیجه گیری نهایی

    هیچگونه تاثیر منفی قابل توجهی بر ویژگیهای فیزیکوشیمیایی و ریولوژیکی، و حسی شکلات پروبیوتیک، شکلات پروبیوتیک ریزپوشانی شده و نمونه شاهد در طی دوره نگهداری دیده نشد و بنابراین نیازی به تغییر در شرایط تکنولوژیکی و دستگاهی و همچنین خرید تجهیزات اضافی برای تولید شکلات پروبیوتیک وجود ندارد.

    کلیدواژگان: ریزپوشانی، شکلات پروبیوتیک، آلژینات سدیم، کنسانتره پروتئین آب پنیر
  • بیوک آقا فرمانی*، سمیه محمدخانی صفحات 129-141

    هدف از این مطالعه، تهیه پودر سفیده و تخم مرغ کامل با استفاده از تیمارهای اسیدی و آنزیمی بود. در روش آنزیمی، گلوگز اکسیداز-کاتالاز (°C30-h 6) برای تخم مرغ کامل مایع (6/7 pH) و سفیده مایع (9 pH) در اینکوباتور شیکردار انجام شد. در روش اسیدی (اسید سیتریک)، برای تخم مرغ کامل مایع، pH ها روی 6/7 (شاهد)، 6/6، 6/5 و 6/4 و برای سفیده تخم مرغ pH ها روی 9 (شاهد)، 8، 7 و 6 تنظیم شده و برای پاستوریزاسیون از بن ماری (°C65-min 5/2) استفاده شد. پاستوریزاسیون سفیده و تخم مرغ مایع بر اساس غیرفعال شدن آنزیم آلفا آمیلاز (با هدف S.senftenbarg 557W) سنجیده شد. پودر تخم مرغ کامل با pH های 6/7 (شاهد) و 6/6 تیره ترین به خاطر حداکثر واکنش مایلارد در مقابل نمونه با pH 6/5 در حد متوسط و نمونه های با pH های 6/7 (تیمار آنزیمی) و 6/4 روشن ترین (حداقل رنگ) بودند. کف کنندگی پودر تخم مرغ بازساخته در 6/4 pH بیشترین (72%) و شاهد (6/7 pH) کمترین (55%) را نشان دادند. نمونه تیمار شده آنزیمی (6/7 pH) قدرت کف کنندگی حدواسطی داشت. تیره ترین نمونه مربوط به پودر سفیده شاهد (9 pH) و روشن ترین رنگ در نمونه های با pH های 9 (تیمار آنزیمی)، 8، 7 و 6 (حداقل رنگ) بودند. نتایج آزمایشات نشان داد که در تهیه پودر سفیده تخم مرغ، نمونه های تیمار شده با آنزیم کمترین قهوه ای شدن را داشتند. پودر سفیده بازساخته با 6 pH بیشترین (82%) و شاهد (9 pH) کمترین (65%) میزان کف کنندگی را نشان دادند و نمونه تیمار شده آنزیمی (9 pH) قدرت کف کنندگی 68% داشت.

    کلیدواژگان: تیمار اسیدی، گلوکز، سیستم آنزیمی، واکنش قهوه ای شدن غیرآنزیمی، قابلیت کف کنندگی
  • بابک قنبرزاده*، لیلا حسینی پور، مصطفی سلطانی، وحید مفید، هدایت حسینی صفحات 143-164

    با توجه به گسترش مصرف دسرهای لبنی و بالابودن میزان قند این فرآورده ها، و از طرفی ارتباط مستقیم مصرف قند با بیماری هایی مانند چاقی، دیابت و امراض قلبی- عروقی، تولید دسرهای لبنی با استفاده از شیرین کننده های کم کالری می تواند از نظر تغذیه ای بسیار مهم باشد. از طرفی با توجه به نقش مهم قند ها در خصوصیات حسی، آب اندازی و بافتی دسر، جایگزینی آنها با شیرین کننده های کم کالری آسان نیست. هدف از این پژوهش بهینه سازی فرمولاسیون دسر لبنی کم کالری با روش طرح آمیخته دی اپتیمال با استفاده از شیرین کننده کم کالری سوکرالوز- سوربیتول در ترکیب با شیرین کننده های قندی رایج یعنی ساکارز و شربت فروکتوز بود. نتایج این تحقیق نشان داد که شکر (ساکارز) را می توان تا حد زیادی با شیرین کننده کم کالری بدون ایجاد عیب در ویژگی های مختلف حسی- بافتی جایگزین نمود و فرمولاسیون بهینه شامل 2/9 درصد ساکارز، 9/3 درصد شربت فروکتوز و 5/81 درصد شیرین کننده سوکرالوز-سوربیتول به دست آمد. آزمون های ریومتری نوسانی و پایا بر روی چهار نمونه شامل دسر حاوی 100% ساکارز ، دسر حاوی100% فروکتوز و دسر حاوی 100% شیرین کننده سوکرالوز-سوربیتول و دسر بهینه کم کالری انجام شد. نتایج نشان داد بالاترین ویسکوزیته ظاهری و بالاترین درجه سودوپلاستیسیته مربوط به نمونه بهینه بود. داده های تنش برشی-سرعت برشی در مدلهای هرشل بالکلی، کراس و کارایی برازش شدند وپارامترهای مدلها به دست آمد. در آزمون ریومتری نوسانی، در تمامی گستره فرکانس، مدول ذخیره بیشتر از مدول افت و وابستگی به فرکانس جزیی بود که نشان دهنده رفتار ژل قوی می باشد. همچنین، نمونه بهینه مدولهای ویسکوالاستیک بالاتری نسبت به نمونه های دیگر داشت.

    کلیدواژگان: دسر لبنی کم کالری، بهینه سازی، رئولوژی، حسی، طرح آمیخته دی اپتیمال
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  • Leila Nateghi *, Peiman Rajaei, Alirezaa Maleki Kahaki Pages 1-15
    Introduction

    Medicinal plants are widely used in traditional culture to treat certain illness all over the world and they are becoming popular in many modern societies among costumers as natural preservatives instead of synthetic chemicals in food products. In fact, they are a great source of antioxidants, which can reduce or stop the oxidation reactions, and their benefits against human diseases and food spoilage has attracted food designers and researchers’ attention. (Yang et al., 2016). Punica granatum; non-productive ancient, mystical, unique pomegranate flower borne on a small, long-living tree, is an important medicinal plant in north of Iran. Various studies have announced that has been used to treat wounds, bronchitis, diarrhea, digestive problems, cardiovascular disease, diabetes, dental conditions, bacterial infections, arthritis and obesity due to its astringent, hemostatic and antimicrobial properties. It is also effectively used to help oral inflammation (Gavanji et al., 2014). Secondary metabolites derived from this flower including total poly phenolic and flavonoid compounds such as gallic acid, ursolic acid, triterpenoids, maslinic acid, acetic acid, punicalagin, and anthocyanin are able to inactivating oxygen-free radicals (Jurenka et al., 2008). These secondary compounds can be found in different parts of the plant consists of leaves, trunk skin, roots, fruit peel, pomegranate juice, seeds and flowers (Salahvarzi et al., 2011). Therefore, the extraction of is Punica granatum utilized in pharmacy, cosmetics and food industries. Soaking is one of the methods mostly used to extract plants effective component which is applied by different solvents in different time and temperature.

    Material and methods

    Formerly, Punica granatum was prepared from Saveh and approved by the herbarium of medicinal plants of the Faculty of Pharmacy, University of Tehran with the scientific name of Punica granatum, pleniflora variety. Thus three soaking variables of solvent type (water and methanol 80%), time (12, 24 and 48 hours) and temperature (20, 35 and 50 °C) were executed for Punica granatum extraction. So 18 treatments were prepared under different conditions of time, temperature and solvent. Total flavonoid by aluminum chloride method, anthocyanin content and IC50 by free radical scavenging activity of Punica granatum extraction were measured. Evaluation of free radical scavenging was conducted with Diphenyl Picrylhydrazyl radical. The IC50 factor, /which demonstrates the amount of required sample to inhibit 50 percent of free radicals, was used. The lower the IC50, the lower concentration with higher antioxidants of extract would prevent oxidation process (Khalili et al., 2015). Confirming its antioxidant properties afterwards, the antimicrobial effect (MIC, MBC) of optimal treatment with two methods of micro dilution broth and diffusion in the well on Staphylococcus aureus, E.coli and Clostridium perfringens were studied. Data were analyzed by one-way variance Duncan test at 95% confidence level by using Minitab 16.

    Results and discussion

    The results of single optimization of independent variables showed the highest flavonoid and anthocyanin content was 8.545 mg/100g during 24h in 35° C using methanol and 6.121 μmol/g during 12h in 50 ° C using water, respectively. The amount of flavonoid and anthocyanin and antioxidant activity enhanced significantly (p≤0.05) over time at higher temperature. Indeed, the solvent has enough time to permeate into plant texture and molecules and the compound can separate from plant matrix and be solved in the solvent. As the increment in temperature decreases the viscosity of solvent and influences the spread rate of it, the mass transfer rate increases. Methanol 80% was more effective to extract antioxidants compared to water. This may be due to solvent polarity since extractability of anthocyanin, flavonoid and phenolic compounds are depended on degree of polarity and ratio of solute and solvent. The polarity of the flavonoid is an important factor to consider; the polarity of the solvent has to be desire for recovery. In addition, the solvent used in the extraction process may have an effect on the bioactivity of the recovered flavonoids. A polar solvent is commonly used for the extraction of isoflavones, flavones, and methylated flavones. In contrast, methanol is sufficient to extract polar flavonoids such as flavonoid glycosides. That’s the reason for ineffectiveness of water to extract total phenols and flavonoids though it can raise the extraction of anthocyanin. Anthocyanin is less stable in higher pH. Methanol raises the pH leading to anthocyanin destruction. The simultaneous optimized condition of Punica granatum extraction to access the most extracted flavonoid and anthocyanin amount and the highest antioxidant properties were predicted during 48h in 50 ° C using methanol solvent with 95/614% acceptability percentage. Under optimum condition 8/6216 mg/g flavonoid, 5/7365 μmol/g anthocyanin and 7.2793 mg/ml IC50 were measured. Based on the results of antimicrobial evaluation of optimized extraction with highest antioxidant activity the highest mean minimum inhibitory concentration(MIC) and the minimum bactericidal concentration (MBC) of Punica granatum against Staphylococcus aureus, E.coli and Clostridium perfringens were observed 468.5 and 1875 μg/ml, 937.5 and 3750 μg/ml , 937/5 and 5000 μg/ml, respectively. The results of the diameter of inhibition zone of Punica granatum extraction showed better antimicrobial effect against Staphylococcus aureus with the diameter of inhibition zone of (13mm) compared to E.coli and Clostridium perfringens. The antimicrobial activity of the Punica granatum extract was more effective against gram positive (S. aureus) compared to Gram-negative (E. coli) bacteria, which are eminent pathogenic microorganisms responsible for food poisoning. A possible explanation for these effects is that Gram-negative bacteria is more resistant. The higher inhibition of Gram-positive bacterium to Gram-negative one is related to structural differences in the cell wall. The Gram-positive bacteria including several layers of peptidoglycans, negatively charged, exhibiting a relatively high level of porosity and permeability. On the other hand, Gram-negative bacteria exposure the cell wall, an additional thoroughly organized outer membrane consisting phospholipids, proteins, lipoproteins and negatively charged lipopolysaccharides, functioning as a hurdle. Consequently, by hydroxyl group of flavonoid and poly phenolic compounds permeating to bacteria cell and bonding their enzymes prevent their metabolism and cause the cell destruction and death.

    Conclusion

    Thus, by optimizing extraction condition a significant amount of antimicrobial and antioxidant compounds of Punica granatum can be extracted and be used in food and pharmaceutical industry.

    Keywords: Antioxidant, Anthocyanin, Flavonoid, Punica granatum, Soaking
  • Mina Seifzadeh * Pages 17-32
    Introduction

    The term shrimp is used to refer to some decapod crustaceans, although the exact animals. Macrobrachium nipponense is a species of freshwater shrimp that was first described in 1849. Macrobrachium nipponense is native of Persian Gulf, Cold Temperature Northwest Pacific, East China Sea, South China Sea, Temperate Northern Pacific and Yellow Sea. This shrimp is native in Japan and Malaysia countries and introduced to China, Iran, Iraq, Philippines, Singapore and Russia. Its distribution is Southern Asia. It is introduced to Bohai Sea, Somali Sea, Sunda Shelf, Yangtze Estuary and Caspian Sea. Common names of Macrobrachium nipponense is Oriental river prawn, Bouquet Nipon, Tenaga ebi, Ho bsia and Camaron nipon. Food items reported for Macrobrachium nipponense is unspecified detritus. Macrobrachium nipponense be able to live in Benthic, freshwater, brackish and Tropical environments. This shrimp classified in Malacostraca, Decapoda and Palaemonidae. Shrimp is important types of seafood that are consumed worldwide. Shrimp is also the most popular type traded worldwide. They can be farmed domestically or caught in the wild. Shrimp as a source of protein a variety of different nutrients. It is rich in antioxidants. Shrimp's benefits include having both omega-3 and omega-6 fatty acids. The cholesterol in shrimp is fairly high, it's not bad for your health. Shrimp is low in calories yet and rich in Nutrients. Approximately 90% of the calories in shrimp come from protein, and the rest come from fat. They play important roles in the food chain and are an important food source. Macrobrachium nipponense is considered one of the most nutritious food sources in the world, which, unlike its high nutritional value, has not been considered for human consumption. Many fermented shrimp products are prepared in different parts of the world and the method of processing depends upon various factors, viz availability of raw materials, consumers preference and the climatic conditions of the region. In addition, shrimp sauce is a product that can be made cheaply from various shrimp raw materials, which are not normally used for food. Human uses of Macrobrachium nipponense is shrimp sauce. Sauces are known in different countries with different names and are commonly used as main dishes or seasonings. Sauce is a liquid condiment made from shrimp that have been coated in salt. It is used as a staple seasoning in East Asian cuisine and Southeast Asian cuisine, particularly Burma, Cambodia, China, Indonesia, Laos, Malaysia, Philippines, Taiwan, Thailand, and Vietnam. Fermentation is one of the oldest techniques in food preservation as it not only extends the shelf-life but also enhances the flavor and nutritional quality of the product. Shrimp sauce, a fermented product. It is a translucent, clear amber yellow or brown liquid, with a salty taste and shrimp flavor obtained from fermentation of a mixture of shrimp and salt, and the fermentation takes not less than 6 months. The product is intended for direct consumption as a seasoning, or condiment, or ingredient for many Asian dishes. it is the main source of protein in the diet and has become a necessity in the house, and it also contains free amino acids and other protein degradation products, essential fatty acids, considerable amount of eicosapentaenoic acid and docosahexaenoic acid that are beneficial to human health. These aroma compounds of the fish sauces were mainly from lipids, amino compounds, and sugars of the raw materials, in which lipid was the major contributor. Although fermented shrimp sauce itself may not be directly used for a physiological functional food because of its high concentration of sodium chloride, the sauce may be useful as a source of biologically active substances, traditional, food supplements in the diet, are widely used in the world as condiments, as flavoring, material, and sometimes as a substitute for the other sauce. The purpose of this study was to determine the chemical, microbial and sensory quality and shelf life of shrimp sauce produced of fresh shrimp from Anzali.

    Material and Methods

    For this research, four treatments including fresh shrimp processed by salt, sorbitol, cooked rice and sucralose were considered. All treatments included 1: 1 salt, acetic acid, sodium sulfate, glutamate and sorbate potassium. Fresh shrimp processed by salt of 1: 1 was as a control sample. The experimental and control treatments were kept at refrigeration temperature for storage period of six months.

    Results and Discussion

    In experimental and control treatments, chemical, microbial and sensory factors showed significant changes during storage (p<0.05). Pseudomonas, Staphylococcus, Coliform, Escherichia coli, yeasts and molds were not observed in test and control treatments. The treatments processed with cooked rice showed better taste and overall acceptance compared to the others (p>0.05). Protein, fat, ash, moisture and salt absorption showed no significant difference among test and control samples (p>0.05). Sorbitol treatment has more moisture and freshness compared with the other treatments (p>0.05). The amount of sauce production in treatment processed by cooked rice has significant increase compared with the other treatments (p<0.05). But, the amount of sauce production in treatment processed by sorbitol has significant decrease compared with the other treatments (p<0.05). The control and test treatments had good quality the end of storage period in the refrigeration.

    Conclusion

    According to the results of the experiments, although the treatments processed with sorbitol were of higher freshness compared to the others, but considering the processed treatments by cooked rice had better taste than other treatments, the significant increase in the amount of sauce produced and overall acceptance of this treatment, therefore treatment processed by cooked rice is recommended for the preparation of sauce from fresh shrimp.

    Keywords: Anzali Wetland, Macrobrachium nipponense, Microbial quality, Shelf life, Shrimp sauce
  • MOHAMMAD REZA MEHRBOD, MOHAMMAD HOJJATI *, Hamid Ezzatpanah Pages 33-48
    Introduction

    Coffee is one of the most popular beverages in the world, which contains large amounts of bioactive compounds and micronutrients that have beneficial effects on human health.Raw and unprocessed coffee beans are green and have a weak flavor and must be roasted before consumption to achieve the desired taste and flavor. The composition of coffee varies greatly during roasting and many factors, including the roasting method, have a great impact on the type and amount of compounds in coffee. Microwave as one of the roasting methods has advantages that have expanded its application in food processing. The aim of this study was to compare the effect of using the microwave as one of the roasting methods on the physicochemical including the moisture content, hardness, instrumental color, antioxidant activity, type and amounts of aromatic compounds, and sensory properties of green coffee beans with the common method of using hot air. For this purpose, 200 g of coffee beans of uniform size were used for each one of the roasting treatments.

    Materials and Methods

    In the present study, Arabica green coffee (Coffea arabica) beans produced in Brazil were roasted using direct oven hot-air (220 °C) for 15 minutes and various microwave powers (650, 750, and 900 watts) for 1.5 minutes. Moisture content was measured by accurately weighing ground coffee samples after drying them in an oven at 105 °C until constant weight. The hardness of coffee beans was investigated using a wedge probe (A/WEG) connected to a Texture Analyzer TA-XT2i equipped with a load cell of 25 kg. Instrumental color characteristics including lightness (L*), redness (a*), and yellowness (b*) were measured using a Konica Minolta Colorimeter CR-400. The antioxidant activity of coffee beans was assessed by DPPH• radical scavenging assay. The aromatic compounds of coffee samples were extracted and identified by the solid-phase microextraction (SPME) method and gas chromatography-mass spectrometry (GC-MS), respectively. Organoleptic attributes of brewed coffee samples including appearance color, odor intensity, taste, and overall acceptability were evaluated with a group of 10-trained panelists using an 11-point scale. All experiments were carried out using a completely randomized factorial design and the data reported were the mean of a minimum of three replicates.One-way analysis of variance (ANOVA) test was taken using SPSS Software and Duncan’s multiple range test was used to show significant differences of the mean values at P ≤ 0.05.

    Results

    The results of data analysis showed that the moisture content of coffee beans was significantly reduced by roasting and the lowest moisture content was observed in coffee roasted by microwave at 900 watts. The results also showed that roasting reduced the hardness of coffee and microwave-roasted beans had less hardness and the lowest texture hardness was observed in microwave-roasted coffee beans at 900 watts. Roasting decreased the lightness (L*) and increased the intensity of redness (a*) and yellowness (b*) of coffee beans, and in microwave-treated samples at higher powers, more differences were observed in the instrumental color characteristics of roasted coffee with the oven. The results revealed that the roasting process reduced the antioxidant activity of coffee in different concentrations; however, microwave-roasted coffees had more antioxidant activity than oven-roasted coffees. The results of the analysis of volatile compounds of coffee samples using solid-phase microextraction method by gas chromatography-mass spectrometer (SPME-GC/MS) showed that the content of total acidic compounds in roasted beans was significantly reduced compared to green coffee beans, while the amounts of alcoholic, ketone, aldehyde, furan, pyrazine and phenolic components in roasted coffees raised significantly compared to green coffee. The results showed that the roasting method had a significant effect on the type and amount of volatile compounds in coffee (p < 0.05). During the roasting process, some compounds were completely destroyed and some new compounds appeared instead. In the present study, the highest amount of volatile compounds was observed in coffee roasted by microwave at 650 watts. Furfuryl alcohol, 2-methylpyrazine γ-butyrolactone, and Pyridine were the predominant volatile compounds in roasted coffee. The results of the sensory evaluation showed that roasting had a significant effect on the sensory properties of coffee, so that roasting increased the acceptance of the appearance color of coffee, and coffee roasted by oven and microwave (650 watts) had the highest score. In addition, coffee roasted by microwave with a power of 650 watts had a significantly higher odor and taste score. Roasted coffee with 650 watts of microwave and oven had the highest overall acceptability, while samples prepared with 900 watts of the microwave with green coffee had the lowest overall acceptability.

    Conclusion

    In conclusion, based on the results of the present study, it could be stated that the use of microwave power at 650 watts due to the ability to create more aromatic components in coffee beans, better sensory acceptance, and more antioxidant activity could be a suitable method for roasting coffee beans.

    Keywords: Coffee, Roasting, Antioxidant Activity, Gas chromatography, Aromatic compounds
  • Saeid Khanzadi *, Abbas Mehraee, Mohammad Hashemi, Mohammad Azizzadeh Pages 49-67
    Introduction

    Shrimp are highly perishable due to the biochemical, microbiological or physical changes during Post-mortem storage, which results in limited shelf life of the product (Farajzadeh et al., 2016). Melanosis is considered a limiting factor for crustacean preservation. This alteration originates by the action of polyphenol oxidase and in some species, as deep-water rose shrimp, also by the action of activated hemocyanin (Martínez-Alvarez et al., 2020). Traditional methods for shrimp preservation such as cold storage, freezing and chilling can’t suppress effectively spoilage (Farajzadeh et al., 2016). Hyssopus officinalis, as valuable medicinal herb, is widely used in traditional medicine. Due to the increased resistance of pathogenic microorganisms to antibiotics and increasing of treatment costs, attentions has been focused to compounds of natural origin (Pirnia et al., 1399). Nano-applications are named as one of the novel methods, which provide high immobilization efficiency for essential oils (keykhosravy e al., 2020). The nanoemulsion is a stable delivery system with unique physicochemical and practical characteristics including high physical stability, optical transparency and high bioavailability (khanzadi et al., 2020). In this study, the effects of chitosan nanoemulsion coating containing Hyssopus officinalis essential oil were investigated on melanosis phenomenon and color evaluation of shrimp samples during 12 days at 4 °C.

    Material and methods

    First, Hyssopus officinalis essential oil was prepared; Hyssop oil was extracted separately by water distillation. The essential oils components were identified by GC/MS (Pirnia et al., 1399). This study includes two phases of edible coating preparation and food modeling. After preparation of chitosan nanoemulsion containing essential oil, particle size and PDI were determined (keykhosravy e al., 2020). A dynamic light scattering (DLS) device (Malvern Instruments Ltd., United Kingdom) was utilized to measure the particle size of the nanoemulsion droplets. The distribution of droplet size was considered in the terms of the mean droplet size (z-diameter) and polydispersity index (PDI) (Moghimi et al., 2016). Then, Shrimp samples were provided and they were immediately placed in insulated polystyrene ice flasks and transported to the laboratory of food hygiene, Ferdowsi university of Mashhad, Mashhad, Iran. The fillets were washed completely for removing external particles (Mohajer et al., 2021). Shrimp samples were randomly divided into ten groups:CON: without any coating solutionCH: Chitosan coatingSCH: Sonicated Chitosan coatingSMS: Sodium Metabisulfite coatingHEO 0.5%: Hyssopus officinalis essential oil (HEO) 0.5% (W/V)HEO 1%: Hyssopus officinalis essential oil (HEO) 1% (W/V)CE+HEO 0.5%: Chitosan coarse emulsion coating containing 0.5% (W/V) HEOCE+HEO 1%: Chitosan coarse emulsion coating containing 1% (W/V) HEONE+HEO 0.5%: Chitosan nanoemulsion coating containing 0.5% (W/V) HEONE+HEO 1%: Chitosan nanoemulsion coating containing 1% (W/V) HEO The prepared samples were covered with different solutions for 2 min and were allowed to drain for 1 h. All the samples were placed into zip packs. Lastly, the samples were kept at 4 ± 1 °C for 12 days and analyzed for color evaluation and melanosis during 2/4-day intervals (days 0, 2, 4, 8 and 12). Lightness (+L), yellowness (+b), and redness (+a) of samples were measured with a Hunterlab colorimeter (Hunter Associates Laboratory, Inc., Reston, Virginia, USA), using a CIELab scale (Salehi et al., 2018). Whiteness (W) was also calculated, as described by Park, 1994 (Park et., 1994). Melanosis or black spot of shrimp was performed based on ocular evaluations (Sani et al., 2017). First, the basic sensory evaluation techniques and characteristics of shrimp meat (taste, smell, color, and texture) were introduced to the members of the group. 21 evaluators (20-38 years) were selected from among the staff and students of the Food Hygiene Laboratory of the Faculty of Veterinary Medicine, Ferdowsi University of Mashhad. The evaluators evaluated the samples in individual panels with sufficient light and randomly. For each evaluator, drinking water was placed for the intervals between testing the samples (keykhosravy et al., 2021). Sensory evaluation was performed using a 4-point scoring technique. In this method, a score of four indicates the absence of black spots on the shrimp and a score of one indicates the presence of black spots across the surface of the shrimp.

    Results and discussion

    33 compounds were identified in Hyssop. Most of its compounds include isopinocamphen (35.45%), pinocamphen (11.81%) and beta-pinene (10.12%). The results are in agreement with Najafpour et al. (2001) and Fraternale et al. (2004). The z-diameter and PDI values of CE+HEO 0.5% were determined to be 570.3 ± 15.83 nm and 0.63±0.07, while for CE+HEO 1% were 402.2 ± 2.50 nm and 0.50±0.05, respectively. Z-diameter of the NE+HEO 1% and NE+HEO 0.5% were measured as 385.7 ± 3.09 nm and 538.9 ± 4.40 nm, and their PDI values were 0.55±0.03 and 0.76±0.01, respectively. Color is the most important visual feature for consumers in seafood. A value is infinite and positive values are equivalent to red and negative values are equivalent to green. B values are infinite and positive values are equivalent to yellow and negative values are equivalent to blue, and L index is equal to the brightness of the image which is between 0 zero equivalent to black and 100 Equivalent to full reflection of light (Salehi et al., 2018). On day 12, the lowest amount of redness and yellowness was observed in the groups of chitosan nanoemulsion containing Hyssopus officinalis essential oil (1% and 0.5%) compared to the control group. The brightness of the samples decreased with increasing storage time in all treatments; one of the reasons for this decrease is due to the appearance of black spots. Chitosan nanoemulsion treatment containing Hyssopus officinalis 1% had the highest score and control, chitosan and sonicated chitosan treatments had the lowest score in terms of melanosis by the end of the period compared to the control.

    Conclusion

    According to the results of this study, chitosan nanoemulsion coating containing Hyssopus officinalis essential oil can maintain the color index in shrimp meat compared to the control group and improve its color and replace synthetic compounds such as sodium metabisulfite as an anti-melanosis compound.

    Keywords: Chitosan, Nanoemulsion, Hyssopus officinalis, Melanosis, Black Spot
  • Masomeh Aghazadeh *, J Nazarzadeh, Gh Dabiri Pages 69-81
    Introduction

    The Oils and fats are considered as one of the most valuable nutrients, rich sources of energy and important precursors in the body's metabolic processes. These compounds play an important role in providing essential fatty acids and fat-soluble nutrients needed by the body. In addition to biological and nutritional role, lipids are important in food processing, determining the quality and organoleptic properties of food products. Edible oils containing high levels of unsaturated fatty acids (especially polyunsaturated fatty acids) are highly susceptible to oxidation. Oxidation of the oil leads to a loss in its organoleptic properties, nutritional value and shelf life, as well as a negative effect on the health of consumers due to the production of undesirable compounds in the oil. Adding antioxidant compounds to refined oils and fats is a common method used by manufacturers to protect these compounds from adverse changes during the storage and processing of food and to extend the shelf life of foods containing lipid compounds. Taking to account the side effects of the synthetic antioxidants, many efforts have been made to identify and extract the antioxidant compounds from plant sources to be used in food and pharmacy as an alternative for synthetic types. Mentha pulegium (L.) plant needs to be further studied in terms of antioxidant activity and phenolic and flavonoid compounds. It is an aromatic plant that grows in many countries and has been considered by various industries, such as food and medicine. This plant is a rich source of natural antioxidants, such as pulegone and other volatile compounds. The aim of this study was to investigate the antioxidant properties of Mentha pulegium (L.) essential oil in Linseed oil in order to select a suitable alternative to synthetic antioxidants such as TBHQ.

    Materials and methods

    In this study, Mentha pulegium (L.) essential oil was extracted by Clevenger (water vapor distillation). Chemical analysis of essential oil by gas chromatography equipped with spectrometer showed approximately 16 different compounds in the essential oil of this plant. Based on the findings obtained from chemical analysis of essential oil, polygon is the most important constituent of essential oil of peppermint plant, which accounts for 51.4%. The obtained essential oil was used in four levels of concentration (0.05%, 0.1%, 0.2% and 0.3%) (w/ w) to observe its effect on delaying oxidation process in Linseed oil. Its oxidant properties were compared with the effect of synthetic antioxidant TBHQ at the concentration level of 0.02% by calculating the determination of acid number and peroxide number during time intervals (zero-7-14-21-28) days. 28) days.

    Results and discussion

    The results indicate that the highest peroxide value of 8.17 (meq/Kg) was related to the control sample on the 28th day and the lowest peroxide value of 3.83 (meq/Kg) was related to the treatment containing TBHQ on the seventh day. Also, the highest acidity value of 2.62 was related to the control sample on the 28th day and the lowest acidity value of 1.88 was related to the TBHQ treatment on the first day. In all treatments of Linseed oil containing Mentha pulegium (L.) essential oil, the resistance time against oxidation was increased with increasing the concentration of essential oil. This indicates that with increasing the concentration of essential oil, the effect of antioxidant compounds in the essential oil in increasing the stability time of flaxseed oil has been increased.In different treatments of Linseed oil on all days, samples containing Mentha pulegium (L.) essential oil with a concentration of 0.3 had the lowest number of peroxide and after those treatments containing 0.2 and 0.1, respectively, showed less resistance to oxidation. The treatment containing TBHQ was less resistant to the oxidation process than these three treatments. Among the treatments, the highest number of peroxides in all days was related to the control sample, which is due to the lack of antioxidants and thus the increase of free radicals in this treatment. The above findings can be inferred from changes in acid number during the experiments.

    Conclusion

    Since Mentha pulegium (L.) essential oil has unique properties, several applications can be attributed to it; So that this natural effective substance can be a suitable alternative to artificial preservatives due to its role of inhibiting the growth of microorganisms and increasing the shelf life of food products. Also, the essential oils of this plant are considered as powerful antioxidants due to their phenolic compounds, so they can be considered as a suitable alternative to synthetic antioxidants whose adverse effects on humans have been proven. On the other hand, the constituents of this essential oil, which are mainly monoterpenes, have a pleasant aroma, and this aromatic plant can be used in various industries to create the desired natural aroma. According to the results obtained from both acid number and peroxide number tests, Mentha pulegium (L.) oil in high concentrations showed a comparable antioxidant effect with the treatment containing TBHQ and can be considered as a suitable alternative to synthetic antioxidants. Keywords: Essential oil, Antioxidant properties, Mentha pulegium (L.), Linseed oil, TBHQ

    Keywords: Essential oil, Antioxidant properties, Mentha pulegium (L.), Linseed oil, TBHQ
  • Parva Abdolahi, Reza Esmaeilzadeh Kenari *, Reza Farahmandfar, Maryam Azizkhani Pages 83-96

    Frying is the process of soaking food in hot oil in relationship with air and food at high temperature (around 140–190° C), during thermal processing, a set of chemical reactions such as hydrolysis, oxidation, thermal decomposition, and polymerization occurs (Keshavarz Moghadam And Moslehishad 2020). Quinoa (Chenopodium quinoa Willd.) is singled out as a food rich in antioxidants (Melini and Melini 2021). Colored quinoa cultivars have been demonstrated to be a good source of phenolics, flavonols, and betalains mainly contained in the quinoa hulls (Laqui-Vilca et al., 2018). The literature has reported the presence lutein and zeaxanthin in the seeds of three quinoa genotype (Multari et al., 2018).Carotenoids are unsaturated hydrocarbons and fat-soluble pigments, which are composed of 8 isoprene units. Thus, their chemical structure consists of ~40 carbon atoms (Mateos and García-Mesa 2006) which can quench singlet oxygen by their numerous conjugated double bonds. The degree of quenching increases as the number of the bonds rises in lutein, zeaxanthin, lycopene, astaxanthin, and isozeaxanthin (Kaur et al., 2015; Steenson and Min, 2000). Carbon dioxide, as the most common solvent used in the supercritical fuid extraction process, can pass through solids like a gas and dissolve substances in itself like a liquid. Therefore, the features of liquid solubility and gaseous permeability, as well as low viscosity under the supercritical conditions, make it possible for carbon dioxide to permeate the plant matrices. In addition, carbon dioxide can be easily separated from extractive materials without leaving toxic compounds in the extract (Salami et al., 2020). In this study, the antioxidant effect of carotenoid extract by supercritical fluid extraction method and commercial beta-carotene on the stabilization of soybean oil was investigated.

    Materials and methods

    Carotenoid extract of red quinoa was extracted by supercritical fluid method with co-solvent 10% and 15% ethanol and then added to soybean oil with commercial beta-carotene at a concentration of 200 ppm. Samples were stored at 60 ° C for 8 days. Peroxide value (PV), conjugated diene (CD) and thiobarbituric acid (TBA) tests and colorimetry were measured to evaluate the effect of carotenoid extract and commercial beta-carotene on the stability of soybean oil.

    Results and discussion

    With increasing storage time, the amount of peroxide in all samples containing antioxidants increased. All samples on the first day of storage had significantly less peroxide than the samples on the last day of storage (P <0.05). Samples containing carotenoid extract by supercritical fluid extraction method with the co-solvent of 10%, 15% ethanol had significantly less peroxide content in most storage days than samples containing commercial beta-carotene (P <0.05). The lowest amount of peroxide on the last day of storage with a value of 7.21 (meq / Kg fat) was related to the sample containing carotenoid extract with supercritical fluid extraction with 15% ethanol solvent. Samples containing beta-carotene and carotenoid extract by supercritical fluid extraction method with the co solvents of 10%, 15% ethanol increased the amount of conjugated diene value with increasing storage time. In general, there was a significant difference in all samples on the first and last day of storage (P <0.05). Samples containing carotenoid extract by supercritical fluid extraction method in most storage days, especially in the last days of storage, compared to samples containing commercial beta-carotene, had significantly less conjugated diene value (P <0.05), which could be due to its higher carotenoid content. On the last day of storage, the sample containing carotenoid extract by supercritical extraction method with the co-solvent of 15% ethanol with the amount of 16.032 mmol / L had the lowest and the sample containing commercial beta-carotene with the amount of 19.60 mmol / L had the highest amount of conjugated diene value. In the early days, the amount of thiobarbituric acid is low, but over time the primary oxidation products increase and begin to decompose, and the amount of this index increases and volatile aldehydes are formed. The amount of thiobarbituric acid in the samples increased with increasing storage time. Samples containing carotenoid extract with supercritical fluid extraction with 10% ethanol from the sixth day and samples containing beta-carotene and carotenoid extract with 15% ethanol on the last day had lower thiobarbituric acid levels than the previous day. Which was due to the oxidation of autooxidation products. Samples containing carotenoid extracts by supercritical fluid extraction method, due to their better antioxidant performance, had significantly lower thiobarbituric acid content than samples containing commercial beta-carotene (P <0.05). In all samples, the value of b * is higher than zero and positive and are in the yellow range and b * index of samples containing carotenoid extracts by supercritical fluid extraction method was higher than commercial beta-carotene due to the yellowing of carotenoid extracts added to oil (p <0.05). Index of a * samples containing commercial beta-carotene and carotenoid extract at a concentration of 200 ppm, there was no significant difference between samples containing commercial beta-carotene during storage at 60 ° C (p > 0.05). The parameter a * in most samples is lower than zero and negative, which may be due to changes in carotenoid pigments in the oil during storage. Carotenoid extracts by supercritical method with the co-solvent ethanol 10%, 15% due to turbidity and yellowish color reduced the transparency of oil samples, so they had significantly less L * than commercial beta-carotene samples (p <0.05).

    Conclusion

    In this study, red quinoa carotenoid extract was extracted using supercritical fluid with the co solvents of 10%, 15% and its antioxidant effect was compared with commercial beta-carotene at a concentration of 200 ppm on the stabilization of antioxidant-free soybean oil. The results of this study showed that the carotenoid extracts by the supercritical fluid extraction method performed better than commercial beta-carotene in reducing the amount of peroxide, conjugate diene and thiobarbituric acid. As a result, carotenoid extract was more effective in oxidative stabilization of soybean oil than commercial beta-carotene. b * index of samples containing carotenoid extracts by supercritical fluid extraction method was higher than commercial beta-carotene. The parameter a * in most samples was lower than zero and negative and the L * index of samples containing carotenoid extract by supercritical fluid extraction method was lower than commercial beta-carotene.

    Keywords: Antioxidant Activity, Carotenoid extract quinoa, oxidative stability, Soybean oil, Supercritical fl
  • Maryam Jafari *, Zahra Osivand, Sara Amiri Samani Pages 97-110
    Introduction

    Urtica is a genus of flowering plants in the family Urticaceae. They have a long history of use as an medicinal plants. The main varieties of the Urtica genus are Urtica dioica L., Urtica urens L., Urtica pilulifera L., Urtica cannabina L., Urtica membranacea Poiret, and Urtica kiovensis Rogoff). Roman nettle (Urtica pilulifera) is widely used in folk remedy to treat hypertension, hyperglycemia and inflammation of some organs while the seeds of this plant can be considered as a potential source for mucilage extraction. Given that in recent years, many studies have focused on finding new hydrocolloids and investigation of their physicochemical and functional properties, the aim of the present study was to optimize the mucilage extraction conditions from Roman nettle seeds in order to achieve maximum extraction yield and optimal physicochemical and functional properties of this hydrocolloid.

    Materials and methods

    The U. pilulifera seeds were purchased from a local market in Chaharmahal andBakhtiari Province, Shahrekord, Iran. The seeds were identified at Medical Plants Research Center. Then the seeds were manually cleaned to remove all foreign matter and stored in a plastic bag at refrigerator before to analysis. At first, proximate analysis of seeds including moisture content, crude oil, crude protein, crude fiber and ash content were determined using the AOAC official methods. Total of carbohydrate was determined by difference. Then, using the response surface method (RSM), the optimal conditions for extracting Roman nettle mucilage were determined. D- Optimal design analysis of the effects of four independent variables, including water to seed ratio (1:5-1:30), temperature (30-85 °C), soaking time (30-240 min) and pH (3-10) was studied on mucilage extraction yield, protein content, emulsion stability and color indices of extracted mucilage. For emulsion stability determination at first, 0.5% solution of mucilage was prepared at 70 ° C. The solution was then cooled and kept at 4 ° C for 24 hours to completely hydration. Oil-in-water emulsion (20% by weight) was prepared and then the emulsion was placed in a hot water bath at 80 ° C for 30 minutes, centrifuged at 1200 g for 10 minutes and finally stability of emulsion was calculated. Color indices including lightness (L*), redness (a*) and yellowness (b*) were measured by Hunterlab model Color flex (US).

    Results

    According to the obtained results, increase in temperature to a certain extent, water to seed ratio and pH had a significant effect (p<0.05) on mucilage extraction yield. Increasing the water-to-seed ratio allows more polysaccharide compounds to be hydrated due to the availability of sufficient water, which increases the thrust force to remove mucilage from the seed. Mucilage extraction yield increased at higher pH which can be due to the release of protein materials and easier release of mucilage. Ttemperature showed a quadratic effect on mucilage extraction yield, so that with increasing temperature to a certain extent, first the amount of mucilage extraction increased, which can be due to the decrease in the viscosity of mucilage attached to the seed and also higher mass transfer rates of soluble polysaccharides at higher temperature. However, a further increase in the extraction temperature showed the negative effect and reduced the extraction yield. This may be due to breaking and hydrolysis of the mucilage structure due to thermal stress in the aqueous medium. The most important and significant factors (p <0.05) on protein content were linear effect of pH, linear effect of time, effect of pH-time interaction, effect of water to seed ratio- time interaction and, quadratic effect of extraction temperature. At lower pH, the protein content of mucilage was significantly (p <0.05) higher than alkaline pH. In general, extraction of mucilage at higher pH and shorter time will lead to extraction of mucilage with minimal protein content may be due to the solubility of proteins in the alkaline pH range. Increasing the water-to-seed ratio also reduced the amount of protein in mucilage, which is probably due to the possibility of more solubility of the protein in the aqueous medium. Among the studied variables, the linear effect of pH, temperature and water-to-seed ratio showed a significant effect on the stability of emulsion containing mucilage (p <0.05). In addition, the interaction of pH and water to seed ratio as well as the interaction of extraction temperature and time, the quadratic effect of pH and the quadratic effect of water to grain ratio were also significant on the changes of this response. Since the presence of proteins with hydrocolloid can show a positive effect on the stability of the emulsion, therefore, the obvious decrease in the stability of emulsions prepared with mucilage extracted at higher pH is probably due to the lower protein content in these samples. What is clear is that when higher water-to-seed ratio and higher pH are used to extract mucilage, it will lead to the weakest emulsion stability. Increasing the water to grain ratio in the extraction stage can lead to the removal of more impurities from the grain and their entry into the mucilage, and thus have a negative effect on the stability of the emulsion. In the study of changes in L* and a* indices, it was found that pH was the only effective variable and with increasing pH, a significant decrease and increase (p<0.05) in lightness and redness indices were observed, respectively. Based on the numerical optimization method, optimized conditions for extraction of Roman nettle seeds mucilage were determined in terms of pH of 4.23, soaking time of 239.9 min, soaking temperature of 45.79 °C, and water to seed ratio of 1:5. Under the optimum conditions, extraction yield, protein content, the highest emulsion stability and L* and a* indices were 11.08%, 14.55%, 50%, 47.59 and 15.05, respectively, which was in good agreement with the predicted values.

    Keywords: Emulsion stability, Mucilage extraction, optimization, Roman nettle
  • Hasan Moharampour *, Akram Pezeshki Najaf Abadi Pages 111-127
    Introduction

    Chocolate is made of cocoa mass and sugar suspended in a cocoa butter matrix (Konar et al., 2016). One of the most important ingredients in chocolate manufacture is cocoa powder, which is a complex blend of proteins, polysaccharides, and lipids (Orkaz et al., 2020)In recent years, the global market of functional foods, especially supplements with probiotics, is expanding rapidly. Probiotics are the live microorganisms that, when administered in adequate amounts, provide health benefits to consumers (Tsuda et al., 2010). The health benefits of probiotics include preventing infectious diarrhea, decreasing cholesterol levels in the blood, reducing symptoms of lactose intolerance, increasing immunity to specific diseases, and acting as an antitumor/anticancer agent. Probiotic efficacy can be enhanced when these microorganisms are integrated into the diet, as interactions with food components can protect microbial cells as they pass through the gastrointestinal tract (Vindeola et al., 2011), influenced by the growing demand for functional chocolates that may help customers improve their health (Orkaz et al., 2020). milk chocolate, in particular, is known to be a source of a variety of physiologically active compounds with significant antioxidant activity, such as flavonoids and polyphenols (Todorovic et al., 2015).

    Material and method

    Probiotic strains B. bifidum were obtained from the Persian Type Culture Collection (PTCC), Tehran, Iran. Bifidobacterium bifidum was grown in 18 mL MRS broth, supplemented with 0.05% L-cysteine hydrochloride (Sigma, Sydney, Australia) MMRS (Modified MRS) to provide an anaerobic environment, at 37 °C for 48 h under anaerobic conditions using the Gas Pak system (Anaerocult A, Darmstadt, Merck, Germany). The cultures were transferred into 180 mL MMRS for B. bifidum and incubated under the same conditions. The cultures were then reactivated by transferring 3–4 times in MRS broth and the cells were harvested by centrifuging at 1500 g for 15 min at 25_C (Eppendorf Centrifuge, 5810R, Hamburg, Germany) and washed twice with sterile 0.1% peptone solution. The final cell concentration was adjusted to 1.0 * 109 Cfu ⁄mL (Zomorodi et al., 2010). Preparation of the microencapsulated solution: The whey protein isolated micro-coating solution was prepared according to Tellioghlu harsa & cabuk (2015) method with some modifications. Thus, first a solution of 8% whey protein isolate was prepared and for protein denaturation, it was heated at 80 ° C for 30 minutes and then cooled to ambient temperature. To prepare the alginate coating solution, first a 2% alginate solution was prepared in sterile distilled water and after sterilization (at 121 ° C for 15 minutes) it was cooled. Microencapsulation of microorganisms: The extrusion technique was used to microencapsulate bacteria. After washing, the cultures were suspended in 5 mL of sterile 0.1% peptone solution and mixed with 20 mL of 2% (w⁄ v) sodium alginate solution and 20 mL of 8 % (w⁄ v) whey protein concentrate solution sterilized at 121_C for 15 min. The cell suspension was injected through a 0.11-mm needle into sterile 0.05 M CaCl2 (Merck, Germany). The beads were allowed to stand for 30 min for jellification, and then rinsed with, and subsequently kept in, sterile 0.1% peptone solution at 4_C. After filtering from sterile filter paper, the seeds were transferred to sterile plates and placed in the freeze dryer for 2 days at -130 ° C for drying, and after drying under sterile conditions, they were powdered.

    Results and discussion

    Evaluation of survival of Bifidobacterium bifidum: Bacterial count results for probiotic chocolate increased from 7.33 Cfu/gr on the first day to 6.15 Cfu/gr on the 30th day and to 4.69 Cfu/gr on the 60th day, indicating that the probiotic chocolate retained its probiotic properties until the 30th day(P<0.05). Bacterial count results for microencapsulated probiotic chocolate increased from 6.48logcfu/gr to 6.33logcfu/gr on the 15th day and to 3.5 Cfu/gr on the 60th day, indicating that the microencapsulated probiotic chocolate retained its probiotic properties until the 15th day. Chocolate is one of the products that with increasing of water activity, the amount of damage to the product and the spoilage of the product is accelerated, and therefore it is necessary to pay much attention to the amount of aw. The results showed that probiotic chocolate has a higher water activity than plain chocolate, but not enough to cause probiotic bacteria activity in it (P<0.05). Investigation of acidity changes: The results indicate that the acidity changes for the control sample after 60 days of storage are 1.14 (in terms of oleic acid percentage). This value starts from 0.89 on the first day for microencapsulated probiotic chocolate and reaches 0.95 (in terms of oleic acid percentage) after 60 days of storage, which is not similar to the acidity changes for the unencapsulated sample, which means the trend of acidity changes is not too different for each of the samples. Probiotics remain in the incubator phase in the chocolate-based environment, so no activity occurs that produces lactic acid products that affect acidity. Investigation of pH changes: It is important to study the pH changes of chocolate samples because pH changes are one of the factors affecting product quality, spoilage and its shelf life. The pH values during the storage period for the probiotic chocolate samples show an almost constant trend. Investigation of moisture changes: The results showed that the moisture content of the control sample is higher than probiotic chocolate and microencapsulated probiotic chocolate, which is due to the smaller particle size in the control sample and thus the ability to absorb high moisture. The high moisture content of microencapsulated chocolate compared to the unencapsulated type is probably due to the presence of hygroscopic substances such as whey protein in the bacterial coatings, which have a high ability to absorb moisture and increase the amount of moisture. Investigation of texture hardness changes: Based on the results of texture hardness measurements, the highest hardness was observed in microencapsulated probiotic chocolate (after 60 days) and the lowest hardness was observed in plain chocolate (after 1 day), which could be due to the effects of the materials used to microencapsulation. Investigation of viscosity and yield value changes of chocolate: In this study the results of viscosity measurements show that due to the smaller size in the control sample and thus its ability to absorb high moisture, the viscosity and yield value of the control sample is higher than probiotic chocolate. In addition, microencapsulated probiotic chocolate has a high moisture absorption capacity compared to the unencapsulated type due to the presence of hygroscopic substances such as whey protein in the coating, resulting in higher viscosity and yield value. Sensory evaluation: results show that the probiotic chocolate containing Bifidobacterium bifidum is not significantly different from the microencapsulated type, by the method of sodium alginate - whey protein gel formation, and also the control sample which indicates that the addition of probiotics to chocolate or microencapsulation of probiotic bacteria did not have a significant effect on the desirability and organoleptic properties of chocolate.

    Conclusion

    There were not seen significant negative effects on physicochemical, rheological and sensory properties of probiotic chocolate, probiotic chocolate and microencapsulated probiotic during the storage time and therefore there is no need to change the technological and device conditions and also purchase additional equipment for probiotic chocolate production.

    Keywords: Microencapsulation, Probiotic chocolate, Sodium alginate, Whey protein concentrate
  • Boukaga Farmani *, Somaye Mohammadkhani Pages 129-141
    Introduction

    Effective factors for increasing the quality of dried egg products have been studied by various researchers (Bergquist, 1995). Non-enzymatic browning (Millard) is the reaction between amino group (proteins/amino acids) and glucose that occurred during production of egg powder, leading to undesirable color and lower nutritional values (Sisak et al., 2006). In order to remove negative effect of glucose from liquid egg before producing the powder, glucose oxidase enzyme is applied to prevent non-enzymatic browning. This enzyme catalyzes the oxidation of glucose to gluconolactone and hydrogen peroxide, which is followed by the production of gluconic acid (Wang et al., 2008). In addition, the hydrogen peroxide produced in the reaction can also kill or inhibit the growth of microorganisms (Dobbenie et al., 1995).

    Materials and Methods

    Eggs were washed, disinfected and separated to be ready for treating and processing. Liquid whole egg and egg white are transferred into glass jars and mixed to become homogeneous. Citric acid treatment (10% solution) and glucose oxidase-catalase mixture were used to eliminate or minimize the effect of glucose in all samples. In enzymatic method, liquid whole egg (pH 7.6) and liquid egg white (pH 9) was treated with glucose oxidase-catalase (30°C-6 h) for removing glucose effect. In the acidic method, citric acid was applied to adjust pH of liquid whole egg on 7.6 (control), 6.6, 5.6 and 4.6 and liquid egg white, on 9 (control), 8, 7 and 6 and then they were pasteurized by water bath (65°C- 2.5min). Pasteurization of white and whole egg was evaluated based on inactivation of alpha-amylase (S. senftenbarg 557W). The measured parameters were pH, non-enzymatic browning color, foaming volume, pasteurization adequacy, sensory properties. Experiments were conducted in completely randomized design with three replicates.

    Results and Discussion

    Powdered eggs should retain maximum physicochemical, appearance color and sensory properties of the fresh egg. The pasteurization index in white and whole egg was based on the killing S. senftenbarg 557W pathogenic bacterium. Therefore, adequacy of pasteurization is measured based on the inactivation of alpha-amylase enzyme (65°C-2.5 min) (da Silva et al., 2017). Evaluation of alpha-amylase activity is a rapid test (starch-iodine complex) to evaluate the pasteurization efficiency of liquid egg products. Decreasing the pH of liquid whole egg from pH 7.6 (control) to pH 4.6 using citric acid (10% solution) resulted in lighter color of the samples. The results showed that after drying pasteurized eggs, the samples with pHs of 7.6 (control) and 6.6 had the darkest color due to maximum non-enzymatic browning reaction. In contrast, samples with pH 5.6 had a moderate color, while samples with pHs of 7.6 (enzymatic treatment) and 4.6 had the brightest color. The results indicated that foaming ability of reconstituted whole egg powders were higher at pHs 5.6 and 4.6 in compared to other pHs. The sample with pH 4.6 and pH 7.6 showed the highest (72%) and the lowest (55%) foaming capacity, respectively. The enzyme-treated sample (pH 7.6) had moderate foaming capacity. Semi-trained sensory assessors were used to evaluate sensory attributes such as color, thermal stability and clotting of egg powder during reconstruction. In terms of moisture according to the national standard of Iran (National Standard 2487, 1396), all samples with different pHs had the standard moisture range (4.5-5%). Regarding the physicochemical properties of egg white, decreasing pH of the samples from pH 9 (control) to 6 pH with citric acid (10% solution), caused the brighter color of the samples. The results showed that sample of egg white dried with pH 9 (control) had the darkest color due to the maximum non-enzymatic browning reaction in contrast the samples with pHs 9 (enzymatic treatment), 8, 7 and 6 lightest color (minimum color reaction). The foaming ability of the reconstituted white powder was higher at pHs 6 and 8 as compared to other pHs such as control and enzymatic treatment, while the foaming capacity was moderate at pH 7. The samples with pH 6 and control (9 pH) had the highest (82%) and the lowest (65%) foaming, respectively. Semi-trained sensory assessors were used to evaluate sensory attributes such as color, thermal stability and clotting of white powder during reconstruction. In terms of moisture according to the national standard of Iran (National Standard 2487, 1396), all samples with different pHs had a standard moisture range (4.5-5%).

    Conclusion

    Glucose is the main problematic component in production of egg powders, which mainly affects the appearance of products and its negative effect is through the non-enzymatic browning reaction. Acidic methods (citric acid) is applied to reduce pH and minimize the effect of glucose as a rapid method and also enzymatic treatment (glucose oxidase-catalase) applied to remove glucose and inhibit the reaction of non-enzymatic browning and subsequently discoloration of powdered samples. The foaming ability of reconstituted powder products was good at low pHs. In contrast, properties such as thermal stability and clotting displayed different behavior at different pHs.

    Keywords: Acid treatment, Glucose, Enzymatic system, Non-enzymatic browning reaction, Foaming ability
  • Babak Ghanbarzadeh *, Leila Hoseinipour, Mostafa Soltani, Vahid Mofid, Hedayat Hosseini Pages 143-164
    Introduction

    Dairy desserts are very popular among different age groups. There is about 10-12% sugar in the formulation of desserts and since sugar plays an important role in the taste, texture, color and other characteristics of food, removing or completely replacing them causes problems in the physico-chemical properties of the final product (McCain et al., 2018). In such products, a combination of low-calorie sweeteners can be used along with bulking agents to provide sensory and textural properties (Di Monaco et al., 2018). One of the most widely used sweeteners in low-calorie products is sucralose, which is derived from sugar, tastes very close to sucrose, is 6 times sweeter than sucrose, and has no aftertaste (Shankar et al., 2013). Due to the low molecular weight of sucralose, it is possible to use sorbitol, which is a 6-carbon sugar alcohol and is slowly metabolized in the body, to improve the textural and sensory characteristics of the dessert (Sheet et al., 2014). One of the statistical methods to minimize the number of trials is the D-optimal mixed design method, which was used to optimize the sensory characteristics and syneresis of the final dessert (Mannarswamy et al., 2010). The aim of this research was to investigate the use of a combination of sweeteners as a substitute for sucrose to achieve a low-calorie dairy dessert with optimized sensory and textural properties with the mixed design method. Finally, the rheological characteristics of the optimized dessert were compared to control dessert samples containing common sweeteners such as fructose, and some rheological models were fitted to predict the behavior of the optimized dessert.

    Material and methods

    In order to prepare the dessert, first all the fixed powder components including skim milk powder (2%), starch (3%) and kappa-carrageenan (0.5%) were combined together to prevent clumping and dissolve better. Then, using a Thermomix device, the powder components were dissolved in fat-free milk (71.5%) and 40% fat cream (10%) at a temperature of 10°C for 5 minutes, and after adding sweeteners (sweetening strength equivalent to 13 % of sugar) according to Table 1-2 were dissolved for 30 minutes at 350 rpm at a temperature of 45°C and finally pasteurized at a temperature of 73°C for 30 seconds and immediately packed in 100 gram containers and at a temperature of 4 °C were kept for 2 days. In order to prepare the sucralose-sorbitol sweetener solution (C), before the dessert production, different percentages of sucralose (from 0.005 to 0.06) were prepared in 20% sorbitol solution and the sample that had the sweetness equivalent of 20% sucrose solution was determined by sensory evaluation method and was used in this research. Then, according to Table 1 the formulations obtained from the experimental design were prepared then syneresis and sensory evaluation including texture, taste, aroma, appearance, sweetness and overall acceptance were performed. The rheological properties of the dessert samples were measured with a MCR-301 rheometer (Anton Paar GmbH, Graz, Austria) and a cone and plate probe with a diameter of 50 mm, an angle of 1 degree, and a gap distance of 0.05 mm.

    Results and discussion

    The experimental design used in this study included three factors with two levels to investigate the relationship and effect of sucrose, fructose, sucralose-sorbitol sweeteners as independent variables on the obtained responses, including syneresis and sensory evaluation as dependent variables. was used (Table 1). The best fitted regression model, which was statistically significant (p<0.0001), was the Special cubic model for syneresis and the Quadratic model for other responses. Formulation optimization was done with the aim of the minimum percentage of sucrose, the minimum amount of syneresis, the best texture, taste, aroma, appearance, the most sweetness and the highest overall acceptance. The optimized formulation containing 9.2% sucrose, 9.3% fructose and 81.5% sucralose-sorbitol was obtained. According to the three-dimensional contour diagrams (Figure 1), the use of the combined sweetener sucralose-sorbitol in high amounts along with fructose syrup improves the textural properties. The graph related to other responses, increasing the concentration of C from low to high level leads to improvement of sensory evaluation results of taste, aroma, appearance, sweetness and overall acceptance. Therefore, it can be concluded that sucralose-sorbitol sweetener is a suitable substitute for sugar to be used in dairy desserts. Oscillatory and steady rheometric tests on 4 samples including dessert with 100% sucrose (sample 1), dessert containing 100% fructose (sample 2) and dessert containing 100% sucralose-sorbitol sweetener (sample 3) and optimized dessert (sample 4) was done. With the increase of shear rate, the apparent viscosity decreased in all samples, which indicates the non-Newtonian (pseudoplastic) behavior. The highest viscosity corresponds to the optimized sample. The effect of sweeteners on the rheological behavior of dessert was fitted well with Hershel–Bulkley, Cross, Carraeu models. Among them, the Cross model due to its high R2 (0.99) and low RMSE, can be a very suitable model for describing the rheological behavior in this research. The results of the investigation of thixotropic properties showed that the largest hysteresis loop area is related to sample number 4 and the lowest is related to sample number 3. Therefore, the presence of different sweetener has led to the production of desserts with higher viscosity but more thixotropic. For oscillatory rheological properties the linear viscoelastic region limit was determined as 1% strain by strain sweep analysis at 1 Hz frequency. We saw an increase in the values for the optimized sample, which indicated the positive effect of the optimized combination of sweeteners on the above parameters.

    Conclusion

    The design expert software and the D-optimal mixture design method were very efficient for designing the formulation of dairy desserts with alternative sweeteners in this research. Special cubic model for syneresis and Quadratic model for other responses of texture, taste, aroma, appearance, sweetness and overall acceptance were reported to be statistically significant. The composition of sugar substitute sweetener was obtained in the optimized formulation including 9.2% sucrose, 9.3% fructose and 81.5% sucralose-sorbitol. In order to check the rheological properties of the rheometric tests on the optimized dessert, the dessert containing 100% sucrose, the dessert containing 100% fructose sweetener and the dessert containing 100% sucralose-sorbitol sweetener were performed. The highest viscosity, the highest degree of pseudoplasticity was related to the optimized sample. Among the fitted models, Cross model is the most suitable model to describe the rheological behavior of dessert in this research due to the highest explanation coefficient (0.99) and the lowest RMSE. The results of oscillatory shear flow tests show the strong gel structure of the produced desserts.

    Keywords: Low calorie dessert, optimization, Rheology, Sensory Properties, D-optimal mixed design