فهرست مطالب

  • سال شانزدهم شماره 5 (پیاپی 65، آذر و دی 1399)
  • تاریخ انتشار: 1399/06/29
  • تعداد عناوین: 12
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  • محسن زندی*، علی گنجلو، ماندانا بی مکر صفحات 507-523

    شرایط نگهداری نامناسب منجر به کاهش کیفیت قابل توجه زالزالک می گردد که بر پذیرش نهایی مصرف کننده موثر است. تاکنون پژوهشی مبنی بر بررسی تاثیر شرایط نگهداری بر تغییرات خصوصیات فیزیکی و شیمیایی میوه زالزالک گزارش نشده است. در پژوهش حاضر تغییرات در خصوصیات فیزیکی و شیمیایی مرتبط با کیفیت میوه طی نگهداری زالزالک تحت شرایط مختلف نگهداری (محیط، یخچالی و سردخانه) مورد ارزیابی قرار گرفت؛ سپس پنچ مدل سینتیکی (مدل های درجه صفر، درجه اول، درجه دوم، تبدیل جزء و ویبال) بر داده های تجربی برازش گردید و پارامترهای مدل توسط تحلیل رگرسیونی محاسبه گردید. شرایط و زمان نگهداری تاثیر معناداری بر خصوصیات فیزیکی و شیمیایی (به غیر از برخی خصوصیات هندسی) داشت و تغییرات قابل توجهی در رنگ، سفتی بافت و افت وزن زالزالک رخ داد. سفتی بافت، اسیدیته قابل تیتر، pH، شاخص رسیدگی، خصوصیات رنگی (به غیر از خصیصه های a* و c*) به طور معناداری کاهش یافت و افت وزن، میزان مواد جامد محلول و خصیصه های a* و c نیز به طور معناداری افزایش پیدا نمودند. نتایج نشان داد که مدل های سینتیکی درجه اول و ویبال بهترین توصیف را از تغییرات خصوصیات فیزیکی و شیمیایی نشان دادند. وابستگی دمایی کیفیت میوه به شرایط نگهداری به طور موفقیت آمیزی توسط معادله آرنیوس توصیف گردید. خروجی این پژوهش نتایج مفید و ارزشمندی برای شرایط و نحوه نگهداری زالزالک فراهم می آورد.

    کلیدواژگان: زالزالک، شرایط نگهداری، مدل سازی سینتیکی، مدل آرنیوس، خصوصیات فیزیکی و شیمیایی
  • مسیح سرفرازی، محبت محبی*، مهدی سعادتمند طرزجان، علی میرشاهی صفحات 525-540

    در این مطالعه، شکر با مخلوط اینولین: مالتودکسترین در نسبت های 75:25 (CH2)، 50:50 (CH3) و 25:75 (CH4) جایگزین شد. سپس گاز دی اکسید کربن در فشار 6 بار به این سه شکلات علاوه بر شکلات حاوی شکر (CH1) تزریق شد تا شکلات حبابدار تولید شود. با استفاده از مقطع نگاری اشعه X از شکلات های حبابدار تصویربرداری شد و پس از پردازش، تصاویر به دست آمده با استفاده از روش چان-وز تقطیع شدند؛ یعنی، حباب ها از سایر قسمت های تصویر جدا شدند. ویژگی های حباب ها که در این تحقیق مورد بررسی قرار گرفتند عبارت بودند از: حجم کل، قطر و نسبت سطح به حجم. همچنین، بلورینگی، چگالی و سختی شکلات ها نیز با هم مقایسه شدند. نتایج نشان دادند که روش چان-وز توانست نویزهای موجود در تصویر را حذف کند. همچنین، نتایج پراش اشعه X نشان داد که نمودار CH3 قله های تیزتری نسبت به CH2 و CH4 دارد که این نشانی از بلورینگی بیشتر آن بود. میانگین قطر حباب های CH1 بیشتر از سایر نمونه ها بود که دلیل آن را می توان به بلورینگی بیشتر آن در مقایسه با نمونه های بدون شکر نسبت داد؛ زیرا ساختار متبلور CH1 از خروج گاز جلوگیری کرده و موجب به هم پیوستن حباب های کوچک و تشکیل حباب های بزرگتر شده است. همچنین، مشاهده شد که در تمام شکلات ها، چگالی شکلات حبابدار کمتر از شکلات بدون حباب است؛ زیرا بخشی از مواد جامد و چربی با گاز دی اکسید کربن جایگزین شد. نتایج اندازه گیری سختی نیز نشان داد که نمونه های بدون شکر حبابدار از نمونه های بدون گاز نرمتر بودند ولی در مورد CH1 عکس این پدیده مشاهده شد که دلیل آن را می توان به حضور شکر در این نمونه نسبت داد؛ زیرا در محصولات حبابدار، ذرات جامد، به ویژه شکر، یک اسکلت پیوسته را تشکیل می دهند و همان نقشی را ایفا می کنند که چربی در محصولات بدون حباب بازی می کند.

    کلیدواژگان: اینولین، مالتودکسترین، مقطع نگاری اشعه X، پراش اشعه X، چانوز، سختی
  • بهاره خلیق، مریم قراچورلو*، پیمانه قاسمی افشار صفحات 541-553

    ناخالصی های روغن و ترکیبات رنگی موجود در آن با استفاده از یک جاذب و طی فرآیند رنگبری از روغن خارج می شوند. در این تحقیق مقادیر مختلفی از اکسید آلومینیوم و منیزیم به خاک رنگبر تجاری افزوده شد. سپس فعال سازی با اسید هیدروکلریک صورت گرفت. رنگبری روغن با افزودن 2 درصد خاک های رنگبر متشکل از درصدهای مختلف سیلیس، اکسیدهای آلومینیوم و منیزیم، اکسیدهای آلومینیوم و منیزیم اسیدی و خاک رنگبر تجاری در مقایسه با نمونه شاهد انجام گرفت. مقدار عدد پراکسید، عدد اسیدی، کلروفیل، کاروتنویید، رنگ زرد و قرمز و مقادیر مس و آهن نمونه های رنگبری شده تعیین گردید. نتایج این پژوهش نشان داد که جاذب های حاوی اکسیدهای آلومینیوم و منیزیم دارای عملکرد یکسان با خاک رنگبر تجاری در کاهش پراکسید نمونه های روغن به میزان 3/96- 9/98 درصد بودند. استفاده از جاذب حاوی 95 درصد خاک تجاری و 5 درصد اکسید آلومینیوم اسیدی باعث کاهش 33/33 درصدی اندیس اسیدی شد. جاذب حاوی 90 درصد خاک تجاری و 10 درصد اکسید منیزیم، کلروفیل را به میزان 96/65 درصد کاهش داد. با استفاده از جاذب حاوی 90 درصد خاک تجاری و 10 درصد اکسید منیزیم، کاروتنویید 40/93 درصد کاهش یافت. جاذب های حاوی 95 درصد خاک تجاری و 5 درصد اکسید آلومینیوم، 95 درصد خاک تجاری و 5 درصد اکسید منیزیم، 95 درصد خاک تجاری و 5 درصد اکسید منیزیم اسیدی عملکرد یکسانی مشابه خاک تجاری در کاهش رنگ قرمز داشتند. مس و آهن در نمونه رنگبری شده با جاذب حاوی 50 درصد خاک تجاری و50 درصد اکسید آلومینیوم و جاذب حاوی 50 درصد خاک تجاری و 50 درصد اکسید منیزیم کاهش 100 درصدی یافتند. نتایج این پژوهش نشان داد اکسیدهای آلومینیوم و منیزیم می تواند عملکرد خاک های رنگبر را بهبود دهند به طوریکه جاذب های حاوی نزدیک به 50 درصد اکسیدهای آلومینیوم و منیزیم نتایج بهتری در رنگبری در مقایسه با جاذب تجاری داشته اند.

    کلیدواژگان: اکسید آلومینیوم، اکسید منیزیم، خاک رنگبر، روغن سویا، رنگبری
  • رضا باتقوا، معصومه مهربان*، احمد احتیاطی صفحات 555-568

    تحقیقات نشان داده است که برخی پپتیدهای زیست فعال با بازدارندگی آنزیم مبدل آنژیوتنسین (ACE)، باعث حفظ انعطاف پذیری دیواره رگ ها و جلوگیری از افزایش فشار خون می شوند. پروتیین سویا به عنوان یک منبع این گونه پپتیدها شناخته شده است. در این تحقیق، از طرح کاملا تصادفی در قالب فاکتوریل برای بررسی اثر افزودن ایزوله پروتیین سویا، پروتیین سویا اکسترود شده و هیدرولیزات پروتیین سویا در سطح های 5 و 10 درصد جایگزین آرد گندم و سه زمان تخمیر 30، 60 و 90 دقیقه، جهت بررسی فعالیت بازدارندگی ACE پپتیدهای جدا شده از خمیر آرد گندم استفاده شد. عصاره آبی خمیر پس از بررسی پروفایل وزن مولکولی به روش SDS-PAGE و اطمینان از حضور غلظت مناسب پپتیدهای با وزن مولکولی کم، از غشای 3 کیلو دالتون عبور داده شد و پپتیدهای زیست فعال جدا شده مورد آزمون قرار گرفت. آنالیز واریانس نتایج نشان داد که نوع پروتیین، درصد جایگزینی و زمان تخمیر با بر شدت درجه هیدرولیز و بر میزان فعالیت بازدارندگی ACE، پپتیدهای زیست فعال جدا شده از خمیر، موثر بودند (P<0.05). مقایسه میانگین نشان داد که خمیر حاوی هیدرولیزات پروتیین سویا بیشترین درجه هیدرولیز را داشت و همچنین بیشترین میزان بازدارندگی ACE در نمونه های حاوی این مشتق پروتیینی مشاهده شد. ایزوله پروتیین سویا و پروتیین سویا اکسترود شده، درجه هیدرولیز متفاوت ولی درصد بازدارندگی ACE مشابهی داشتند. بر اساس نتایج حاصل شده، جایگزینی آرد گندم با 5 درصد از هیدرولیزات پروتیین سویا تولید گونه های پپتید موثر در بازدارندگی ACE در خمیر را تا حد بازدارندگی بیشتر از 83 درصد امکان پذیر می سازد.

    کلیدواژگان: آنزیم مبدل آنژیوتنسین، ایزوله پروتئین سویا، پروتئین سویا اکسترود، نان، هیدرولیزات
  • محیا اورجی، مزدک علیمی*، علی معتمدزادگان، شیرین شکوهی صفحات 569-580

    در بین حبوبات مختلف، باقلا حاوی مقدار زیادی پروتیین، فیبر، ویتامین های گروه B و مواد معدنی است که می توان با هدف توسعه مواد غذایی نوین با مشخصات تغذیه ای بهبود یافته مورد استفاده قرار گیرد. در این پژوهش جهت بهینه سازی استخراج و اصلاح ویژگی های فیزیکوشیمیایی پروتیین و فیبر باقلا، از اولتراسوند و هیدرولیز آنزیمی استفاده شد. به طوری که پروتیین های باقلا تحت تاثیر اولتراسوند در قدرت های 200، 300 و 400  وات و در طی مدت زمان های 15، 25 و 35 دقیقه و آنزیم آلکالاز 2.4 LFG در دوز های مصرفی 15/0، 3/0 و 45/0 درصد در مدت زمان های 15، 25 و 35 دقیقه استخراج و تیمار ها توسط نرم افزار دیزاین اکسپرت طراحی شدند. استخراج فیبر باقلا، تحت شرایط قلیایی از محلول 0012/0، 012/0 و 12/0 درصد هیدروکسید سدیم تا رسیدن به pH 12، 11 و 10  و آنزیم Termamy 2x جهت هیدرولیز آنزیمی استفاده شد. نتایج نشان داد، استفاده از اولتراسوند و هیدرولیز آنزیمی تاثیر مثبتی در حلالیت، ظرفیت جذب روغن و میزان خاصیت امولسیون کنندگی نمونه های پروتیین باقلا داشت. همچنین پتانسیل زتا تمام تیمارها منفی بود، که نشان می دهد محلول تیمار های پروتیین باقلا حاوی آمینواسید هایی با بار منفی بیشتری نسبت به اسید های آمینه با بار مثبت است. در بین نمونه های فیبر باقلا، نمونه فیبر با pH 10 بالاترین ظرفیت نگهداری آب و بالاترین سطح G' که نشان دهنده وجود ویژگی جامد و الاستیکی بیشتری نسبت به دو نمونه دیگر است را نشان داد. همچنین در تمامی نمونه های فیبر، با افزایش سرعت برشی، ویسکوزیته کاهش یافت و یک رفتار رقیق شونده با برش یا سودوپلاستیک از خود نشان دادند.

    کلیدواژگان: باقلا، استخراج، پروتئین، فیبر
  • مهیار راد*، حامد غفوری، زهره غلامی صفحات 581-605

    قارچ های خوراکی از فسادپذیرترین محصولات هستند و بلافاصله بعد از برداشت شروع به از دست دادن کیفیت می کنند که ماندگاری کوتاه این محصولات منجر به ایجاد مشکلاتی در هنگام پخش و بازاریابی این محصول به صورت تازه می شود. پوشش های خوراکی وسیله ای مناسب برای طولانی کردن عمر مفید مواد غذایی و افزایش کیفیت آنها بدون ایجاد آلودگی محیط زیست هستند. در این تحقیق بررسی امکان افزایش ماندگاری قارچ دکمه ای با استفاده از آنزیم بری و بعد پوشش دهی با کربوکسی متیل سلولز و متابی سولفیت سدیم مورد مطالعه قرار گرفت. متغیرهای مستقل شامل غلظت کربوکسی متیل سلولز و متابی سولفیت سدیم (صفر تا 2 درصد) و مدت زمان نگهداری تا 16 روز در دمای 4 درجه سانتی گراد بودند. آزمایشات بر اساس 3 فاکتور سه سطحی حاوی 6 نقطه مرکزی بعد از صفر و 4 و 8 و 16 روز نگهداری در دمای 4 درجه سانتی گراد طراحی شد. آزمایش های انجام شده روی قارچ دکمه ای شامل اندازه گیری  pH، درصد افت وزن، مواد جامد محلول، بافت، رنگ، میزان قهوه ای شدن، شمارش کلی میکروارگانیسم ها و شمارش کپک و مخمر بود. نتایج در این پژوهش نشان داد که نمونه پوشش داده شده با غلظت 2 درصد کربوکسی متیل سلولز به همراه غلظت 2 درصد متابی سولفیت سدیم باعث افزایش pH و میزان مواد جامد محلول گردید. کمترین مقدار شمارش کلی میکروارگانیسم ها و شمارش کپک و مخمر بعداز 16 روز نگهداری در دمای 4 درجه سانتی گراد در نمونه پوشش داده شده با غلظت 2درصد کربوکسی متیل سلولز به همراه غلظت 2درصد متابی سولفیت سدیم مشاهده شد. همچنین کمترین تغییرات رنگ، افت وزن و کاهش در سفتی بافت در این نمونه مشاهده گردید. بر اساس نتایج این پژوهش، پوشش های کربوکسی متیل سلولز و متابی سولفیت سدیم را می توان به عنوان یک ماده پوشش دهنده مناسب برای حفظ خصوصیات ارگانولپتیکی، شیمیایی، میکروبی و ماندگاری قارچ دکمه ای مورد استفاده قرار داد.

    کلیدواژگان: پوشش خوراکی، قارچ دکمه ای، کربوکسی متیل سلولز، متابی سولفیت سدیم، ماندگاری
  • مهران اعلمی*، بهاره فتحی صفحات 607-619

    ارزن یکی از غلات مقاوم به خشکسالی، آفت و بیماری و دارای فصل رشد کوتاه است. دانه های ارزن فاقد گلوتن بوده و می تواند در تولید محصولات غذایی برای بیماران سلیاکی استفاده شود. با توجه به کیفیت پایین محصولات پخت حاصل از غلات بدون گلوتن می توان از افزودنی ها و تیمار فیزیکی آرد برای بهبود ویژگی های پخت استفاده نمود. از این رو در تحقیق حاضر از تیمار حرارتی-رطوبتی دانه های ارزن به عنوان روشی برای اصلاح ویژگی های آرد استفاده شد. در این پژوهش، تاثیر تیمار حرارتی-رطوبتی دانه های ارزن پروسو با رطوبت 20، 25 و 30 درصد در دماهای 100 و 120 درجه سانتی گراد به مدت 3 ساعت بر روی ویژگی های مختلف خمیر (ثقل ویژه و ویسکوزیته) و کیک (حجم، رنگ، رطوبت و سفتی در طول نگهداری، ریزساختار) مورد ارزیابی قرار گرفت. افزایش دما و رطوبت تیمار به طور معنی داری در سطح اطمینان 95 درصد ویسکوزیته خمیر و همچنین تیرگی و قرمزی رنگ کیک را افزایش داد. نمونه های تیمار شده در رطوبت و دمای کمتر موجب افزایش حجم کیک نسبت به نمونه شاهد شدند در حالی که در نمونه های تیمار شده در رطوبت و دمای بالاتر، بهبودی در حجم کیک مشاهده نگردید. با این حال در روز پخت و در طول نگهداری، بهبودی در بافت و میزان رطوبت مغز کیک در اثر تیمار حرارتی-رطوبتی دانه های ارزن ایجاد نگردید. بررسی ریزساختار کیک نشان داد که تیمار حرارتی-رطوبتی دانه ارزن موجب افزایش حفرات ریز و یکنواخت در بافت کیک گردید. بر اساس یافته های این پژوهش، تیمار حرارتی-رطوبتی ارزن می تواند روش مناسبی برای بهبود کیفیت کیک بدون گلوتن باشد.

    کلیدواژگان: دانه ارزن، تیمار حرارتی-رطوبتی، کیک، بدون گلوتن
  • مریم کشانی، نفیسه زمین دار*، رضا حاجیان صفحات 621-628

    از نکات مهم در فرایند مواد غذایی منجمد، انجمادزدایی با حداقل آسیب به ویژگی‎های کیفی آن است. با توجه به اینکه روش های معمول مورد استفاده برای رفع انجماد موادغذایی سرعت کمی داشته و باعث کاهش کیفیت محصول می شوند، استفاده از روش های انجمادزدایی کارآمد ضروری به نظر می رسد. انجمادزدایی اهمیک یک روش حرارتی- الکتریکی با توانایی تولید گرمای یکنواخت تر نسبت به دیگر روش های انجمادزدایی می باشد. در این روش با تعیین میزان جریان الکتریکی گذرا از محصول می توان سرعت انجمادزدایی را تغییر داد. در این پژوهش تاثیر انجمادزدایی مکعب های منجمد ماهی تن با روش اهمیک به صورت غوطه وری در ولتاژ 50، فرکانس ثابت 50 هرتز و در سه غلظت مختلف آب نمک (3/0، 4/0، 5/0درصد) مورد بررسی قرار گرفت و خواص شیمیایی و فیزیکی نمونه ها طی سه روز نگهداری در دمای 4 درجه سانتی گراد بعد از انجمادزدایی اندازه گیری شد. مطابق با نتایج آزمون تجزیه واریانس طرح کاملا تصادفی، گذشت زمان باعث افزایش حلالیت پروتیین، pH، کل نیتروژن فرار باند شده، کاهش افت سانتریفوژ و افشره دارای اسانس گردید. اثر غلظت بر سرعت رفع انجماد معنی دار نبود ولی بر افت انجمادزدایی، افت تبخیر، افت سانتریفوژ، تلفات عصاره و کل نیتروژن فرار باند شده در سطح احتمال 5% اثر معنی داری نشان داد.

    کلیدواژگان: ماهی تن، انجمادزدایی اهمیک، ازت فرار، حلالیت پروتئین
  • مریم سادات ستوده، نفیسه سلطانی زاده* صفحات 629-641

    هدف از این پژوهش بررسی نقش اندازه ذرات آرد سوخاری و اثر افزودن ایزوله پروتیین سویا به آرد سوخاری و خمیرآبه بر ویژگی های ناگت مرغ بود. آرد سوخاری در سه اندازه ریز، متوسط و درشت تهیه شد. سپس 3 درصد ایزوله پروتیین سویا به طور جداگانه یک بار به آرد سوخاری با اندازه ذرات متفاوت و یک بار به خمیرآبه افزوده شد و در تهیه ناگت مورد استفاده قرار گرفت. در نهایت، مقدار جذب آرد سوخاری، میزان رطوبت، افت پخت، تخلخل، جذب روغن، رنگ و ویژگی های بافتی ناگت های مرغ مورد ارزیابی قرار گرفت. بر اساس نتایج به دست آمده ناگت های مرغ پوشش داده شده با ذرات آرد سوخاری ریز، بیشترین محتوی رطوبت و کمترین تخلخل و جذب روغن را داشتند. استفاده از ایزوله پروتیین سویا در خمیرآبه تغییرات قابل توجهی در خصوصیات بافتی ایجاد کرد اما تاثیر معنی داری بر رنگ نداشت. این در حالی است که افزودن ایزوله پروتیین سویا به آرد سوخاری اثر معنی دار بیشتری در نگهداری رطوبت و کاهش افت پخت، تخلخل و جذب روغن نشان داد. همچنین براساس نتایج به دست آمده افزودن ایزوله پروتیین سویا به آرد سوخاری تاثیر معنی داری در کاهش جذب روغن و بهبود ویژگی های ناگت مرغ نسبت به افزودن این ترکیب به خمیرآبه داشت. به طور کلی استفاده از آرد سوخاری ریز که دارای 3 درصد ایزوله پروتیین سویا است می تواند نقش قابل توجهی در بهبود ویژگی های کیفی و تغذیه ای ناگت مرغ داشته باشد.

    کلیدواژگان: ایزوله پروتئین سویا، ناگت مرغ، آرد سوخاری، لایه خمیرآبه
  • هادی تناور، حسن برزگر*، بهروز علیزاده بهبهانی، محمدامین مهرنیا صفحات 643-653

    گیاه پونه با نام علمی Mentha pulegium متعلق به خانواده نعناعیان است. در این پژوهش پس از استخراج اسانس به روش تقطیر با آب، ترکیبات شیمیایی اسانس با استفاده از دستگاه کروماتوگرافی گازی متصل به طیف سنج جرمی شناسایی شد. فعالیت آنتیکسیدانی اسانس پونه به روش های بررسی توانایی مهارکنندگی رادیکال DPPH و ABTS و همچنین میزان مقاومت در برابر اکسیداسیون لینولییک اسید و تغییر رنگ بتاکاروتن بررسی شد. سنجش میزان ترکیبات فنلی کل با استفاده از روش فولین سیوکالتو محاسبه گردید. تعیین میزان فلاونویید به روش رنگ سنجی آلومینیوم کلراید صورت گرفت. اثر سایتوتوکسیک اسانس پونه در غلظت های مختلف اسانس (1، 125/3، 25/6، 5/12، 25، 50، 100 و 200 میلی گرم بر میلی لیتر) در برابر رده سلولی سرطان روده بزرگ (HT29) با استفاده از روش MTT بررسی شد. نتایج نشان داد که اسانس پونه دارای 25 ترکیب است که عمده ترین ترکیبات شیمیایی موجود در آن شامل دی ال- لیمونن 44/28%، دی- کاروون 76/18%، اوکالیپتول 86/8% و پولگون 65/8% بود. میزان مهار رادیکال های آزاد اسانس پونه با DPPH و ABTS به ترتیب 5/51% و 43/53% بود. میزان مقاومت اسانس پونه در برابر اکسیداسیون لینولییک اسید و تغییر رنگ بتاکاروتن برابر با 22/59 درصد بود. میزان فنل کل اسانس و فلاونویید به ترتیب برابر با 35/73 میلی گرم گالیک اسید بر گرم اسانس و 9/19 میلی گرم کویرستین بر اکی والان بود. نتایج اثر سایتوتوکسیک اسانس پونه نشان داد که درصد زنده مانی سلول های HT29 به ترتیب 100، 21/70، 26/61، 98/51، 12/35، 44/24، 65/18 و 92/10 بود. براساس نتایج به دست آمده با افزایش غلظت اسانس پونه، تاثیر بر رده سلولی HT29 افزایش یافته و درصد زنده مانی سلول های HT29 کاهش یافت.

    کلیدواژگان: اسانس پونه، بتاکاروتن لینولئیک اسید، فلاونوئید کل، کروماتوگرافی گازی
  • شیما نصیری، سامان آبدانان مهدی زاده*، مختار حیدری صفحات 655-667

    استحکام محصولات یکی از عوامل مهم و تاثیرگذار در میزان بازارپسندی و همچنین تعیین کیفیت میوه ها به خصوص "به" می باشد. لذا در پژوهش حاضر پس از تعیین مجموعه ای از تغییرات فیزیکی و شیمیایی میوه، پاسخ صوتی آن طی مدت زمان 4 ماه (هر 15 روز یک بار) مورد بررسی قرار گرفت. به منظور تعیین سفتی میوه به صورت غیرمخرب چهار ویژگی (پیک آکوستیک، حداکثر فشار آکوستیک، میانگین فشار آکوستیک و فرکانس طبیعی) استخراج و با استفاده از برنامه نویسی ژنتیک و شبکه عصبی مدل سازی انجام و با مدل های موجود (FI و SIQ-FT) مقایسه گردید. در این مطالعه نشان داده شد که مدل سازی به روش برنامه نویسی ژنتیک و شبکه عصبی با ضریب همبستگی به ترتیب 9567/0 و 933/0 دارای عملکردی مطلوب تری در پیش بینی مقدار سفتی محصول "به" نسبت به مدل های موجود FI و SIQ-FT با ضریب همبستگی به ترتیب 601/0 و 754/0 دارند.

    کلیدواژگان: برنامه نویسی ژنتیک، شبکه عصبی، به، انبارمانی، سفتی
  • فروزان جلالی زند، محمد گلی* صفحات 669-685

    در این تحقیق با کپسوله کردن، سلنیوم به عنوان ریزمغذی حیاتی و آنتی اکسیدان طبیعی جایگزین آنتی اکسیدان های سنتزی با آثار سوء شد. سلنیت سدیم با غلظت های (100، 300، 500، 700 و 900 میلی گرم در 20 میلی لیتر محلول اسپری شونده) با ترکیبی از مواد دیواره شامل صمغ عربی (25، 26، 27، 28 و 29 درصد) و صمغ فارسی متناظر آن (5، 4، 3، 2 و 1 درصد) به روش تبخیر حلال پرداخته شد. دو فرمول بهینه شامل، بهینه یک و دو به‎ترتیب 390 پی پی ام و480 پی پی ام کپسول (معادل 6/8 پی پی ام نمک سلنیت سدیم)، آنتی اکسیدان سنتزی بوتیل هیدروکسی آنیزول (200 پی پی ام) و نمک سلنیت سدیم (6/8 پی پپی ام) به روغن سویای فاقد آنتی اکسیدان اضافه شد. سپس اندیس پراکسید، اسیدیته، تیوباربیتوریک اسید، عدد آنیزیدین، عدد توتوکس و فعالیت آنتی اکسیدانی آن ها در روغن سویای فاقد آنتی اکسیدان در طول مدت زمان (صفر، 180 و 360 روز) با کمک نرم افزاز SPSS آنالیز شد. با حضور آنتی اکسیدان سلنیت سدیم کپسوله شده و آنتی اکسیدان سنتزی بوتیل هیدروکسی آنیزول در روغن سویا، عدد پراکسید، اسیدیته، تیوباربیتوریک اسید، عدد آنیزیدین، عدد توتوکس کاهش و فعالیت آنتی اکسیدانی افزایش معنی دار یافت(05/0>P). بر حسب تاثیرات مثبت آنتی اکسیدانی در روغن سویا ترتیب تیمارهای موثر و پیشنهادی این تحقیق شامل: بهینه 2> بهینه 1≥ آنتی اکسیدان بوتیل هیدروکسی آنیزول> نمک سلنیت سدیم> شاهد فاقد آنتی اکسیدان گزارش شد. نتایج حاصل از این پژوهش می تواند استفاده از آنتی اکسیدان سلنیت سدیم کپسوله شده (بهینه 1و 2) به عنوان جایگزین آنتی اکسیدان سنتزی بوتیل هیدروکسی آنیزول جهت افزایش ماندگاری روغن سویا را پیشنهاد نماید.

    کلیدواژگان: میکروکپسولاسیون، صمغ عربی- فارسی، سلنیت سدیم، فعالیت آنتی اکسیدانی، روغن سویا
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  • Mohsen Zandi*, Ali Ganjloo, Mandana Bimakr Pages 507-523
    Introduction

    Hawthorn (Crataegus pinnatifida), belonging to the Rosaceae family, consists of small trees and shrubs. The color of the ripe fruit varied from yellow, through green to red and on to dark purple. Most of the species ripen their fruit in early to mid-autumn. Beneficial effects of hawthorn fruit extracts have been confirmed by various studies. Pharmacological data showed that hawthorn fruit and its preparations enhance myocardial contraction and conductivity, protect against ischemia. They have a sedative action, a protective effect against arrhythmia and increase of coronary vessel flow. They have also positive effects on the cardiovascular system. Hawthorn is one of the most widely consumed horticultural products, either in fresh or processed form. It is also an important component of many processed food products because of its excellent flavor, attractive color and high content of many macro- and micro-nutrients. Uncertain storage conditions lead to considerable quality loss in hawthorn fruits, which affect their consumer acceptability. Properties such as color, firmness and moisture provide valuable information for the monitoring of quality changes in postharvest fruits because of their reliability and rapid and easy measurement. These changes are consequences of many biochemical and physiological processes that occur during fruit ripening, such as respiration and transpiration. In addition, these changes depend on the external conditions to which the fruit is exposed. To estimate changes in fruit quality as a function of storage conditions, the evolution of certain quality-indicative properties such as color, firmness or weight can be used to provide related information on the quality grade of the product stored. Kinetic models can be used as tools to describe quantitative physicochemical changes in foods during processing. Kinetic models can be linear or non-linear forms of rate law equations. The rate process of food constituents is usually defined by zero, first or second order kinetics.

    Method and material

    In this study, changes in physicochemical characteristics associated with fruit quality were investigated during various hawthorn fruit storage conditions include: cold (1ºC and RH=90%), refrigerator (10 ºC and RH=85%) and room conditions (25 ºC and RH=60%). Color quality parameters (L*, a*, b*, C*, h* and ΔE), geometrical parameters, weight loss, firmness, total soluble solid (TSS), pH, titratable acidity (TA) and ripening index (RPI) were the measured factors. Different mathematical models were successfully proposed and adjusted to represent the change in physicochemical properties as a function of storage temperature. Among various kinetics model, five models (Zero-order, First-order, Second-order, Fractional conversion and Weibull models) were fitted to experimental data and model parameters in equations were determined by multiple regression analysis.

    Result and discussion

    Storage of hawthorn fruits at different temperature affected their color (L*, a*, b*, C*, h* and ΔE), geometrical, physical (weight loss, firmness) and chemical properties (TSS, pH, TA and RPI). Storage at all conditions had significant impact on the physicochemical parameters analyzed (except some geometrical characteristics). Significant alterations in hawthorn color, firmness and weight loss were observed. The firmness, titratable acidity, pH, ripening index, color characteristics (except a* and C*) decreased while weight loss, total soluble solid, a* and C* increased significantly (p<0.05). Hawthorn stored at low temperatures revealed a delay on quality reduction reactions in terms of color, firmness and weight loss. The results indicated that the First-order and Weibull kinetic models provided the best prediction of the changes in physicochemical parameters. The storage temperature effect was successfully described by the Arrhenius law. Understanding the mechanisms in which these conditions affect the quality changes processes is of great importance because it allows their appropriate modification to maintain quality and maximize storage time. The outcomes of this study provide additional and useful information for hawthorn fruits under various storage conditions.

    Keywords: hawthorn fruits, storage conditions, kinetic modeling, Arrhenius model, physicochemical characteristics
  • Messiah Sarfarazi, Mohebbat Mohebbi*, Mahdi Saadatmand Tarzjan, Ali Mirshahi Pages 525-540
    Introduction

    Chocolate is a suspension of solid particles, including sugar, cocoa solids and milk powder (depending on the chocolate type) in a continuous fat phase, namely cocoa butter or its substitutes. The solid particles account for approximately 70% of chocolate with the fat constituting about 30%. Sugar takes up nearly 40–50% of the total solid particles of chocolate, thus influencing its sweetness, particle size distribution, rheological and sensory properties. It is also considered to be a bulking agent and a source of energy which produces 394 kcal/100 g of refined sugar. Therefore, consumers are increasingly becoming concerned with chocolate sugar and calorie content nowadays. This issue can be resolved by replacing sugar with bulk (nutritive) sweeteners and/or dietary fibers. Bubbles are found in many food products, including cakes, chocolates and beverages. Although they do not increase the food nutritional value, they change its textural properties and mouthfeel. Bubbles are normally visible to the naked eye and their mean diameter ranges from 0.05 to 3 mm. X-ray computed tomography is a 3D imaging technique which captures the images of a sample cross-sections. It is used for the non-destructive visualization and characterization of food microstructure. In this method, a series of radiographs of a sample are captured from different angles to be utilized for the 3D reconstruction of the material microstructure.

    Materials and methods

    sugar was replaced with inulin: maltodextrin mixture at ratios of 25:75 (CH2), 50:50 (CH3) and 75:25 (CH4). Carbon dioxide was injected into the samples at 6 bar to produce aerated chocolate. Using X-ray computed tomography, the images of the samples were captured and after processing, the obtained images were segmented using the Chan-Vese method. The properties of bubbles included total volume, diameter and surface to volume ratio. The crystallinity of the samples was determined through X-ray diffraction. The hardness of the chocolate bars was measured using the puncture test. The density of the aerated chocolates was also compared with that of the nonaerated ones.

    Results and discussion

    X-ray diffraction revealed that there were many strong peaks in the diffractogram of CH1, which can be ascribed to the high degree of sugar crystallinity in addition to the impurities present in the commercial sugar utilized in this study. In the case of the sugar-free samples, namely CH2, CH3 and CH4, two distinct peaks could be seen at 2θ of about 21° and 23.5°, both of which were much stronger and more defined in the scattering pattern of CH3, demonstrating the more crystalline structure of this sample. It seems that inulin and maltodextrin have physically interacted with each other or with the other ingredients of the chocolate, in particular CBS, which has been more pronounced at the ratio of 50:50. The results of image segmentation showed that the Chan-Vese method, compared with the adaptive thresholding one, was more able to segment the images, because this method does not depend on the image gradient and is especially suitable for the objects with vague edges. The mean bubble diameter of CH1 was bigger than that of the other samples, which could be due to its higher degree of crystallinity, because the crystalline structure of CH1 prevented the gas from being lost leading to the coalescence of smaller bubbles and the formation of bigger ones. In addition, it was observed that the density of the aerated chocolate was higher than that of the unaerated one in all the formulas as a portion of solid particles and fat was replaced with the gas. The results also demonstrated that the sugar-free aerated samples were softer than the corresponding nonaerated ones. However, it was reversed in the case of CH1 which could be ascribed to the presence of sugar in this sample, because in aerated products, solid particles, particularly sugar, form a continuous skeleton and play the same role as fat does in nonaerated products.

    Keywords: inulin, maltodextrin, X-ray computed tomography, X-ray diffraction, Chan-Vese, Hardness
  • Bahareh Khaligh, Maryam Gharachorloo*, Peymaneh Ghasemi Afshar Pages 541-553
    Introduction

    The impurities of the oil and its pigments are basically removed from the oil by physical adsorption using an adsorbent during the bleaching process. The bleaching process involves the removal of pigments, impurities, metals and oxidation products. Removal of these substances is essential in oil refining because it improves the stability, appearance and sensory quality of the oil. Activated bleaching earth is the most commonly used adsorbent for purifying and improving the color of fats and oils. The bleaching process of edible oils is important for producing light colored oils with acceptable quality. The aim of this study was to evaluate the physical and chemical properties of soybean oil bleached with bleaching earth containing increased amounts of aluminum and magnesium oxides.

    Material and Methods

    Bleaching earth was purchased from Kanisaz Jam Company. Degummed and neutralized soybean oil was obtained from Behshahr Vegetable Oil Company. Different amounts of aluminum oxide and magnesium oxide were added to commercial bleaching earth. Activation of the adsorbents was performed with hydrochloric acid and oil bleached at 110°C for 30 min under vacuum by adding 2% of adsorbent containing different percentages of silica, aluminum and magnesium oxides. A series of physical and chemical tests such as peroxide value, acid value, chlorophyll content, carotenoid content, yellow and red colors and amounts of copper and iron were then carried out on the neutralized and bleached oils according to the standard methods. All the experiments and/or measurements were carried out in triplicate. Data were statistically analyzed using the Statistical Analysis System software package on replicated test data. Analysis of variance was performed by application of an ANOVA procedure. Significant differences between the means were determined using the Duncan multiple range test.

    Result and Discussion

    The results of this study showed that the examined adsorbents reduced the peroxide value to 98.9-96.3%. Application of the adsorbents containing 95% commercial bleaching earth - 5% aluminum oxide and 95% commercial bleaching earth - 5% acidic aluminum oxide reduced the acid value by 33.33% and 26.66%, respectively. The amount of chlorophyll in the control sample was 7.58 mg Pheophytin A/kg oil, which reduced 65.66% by using adsorbent containing 90% commercial bleaching earth and 10% magnesium oxide and reached to 1.90 mg Pheophytin A/kg. The amount of carotenoids in the control sample was 7.88 mg/kg. Using the adsorbent containing 90% commercial bleaching earth and 10% magnesium oxide decreased carotenoids up to 93.40%. Adsorbents containing 95% commercial bleaching earth and 5% aluminum oxide, 95% commercial bleaching earth and 5% magnesium oxide, 95% commercial bleaching earth and 5% acidic magnesium oxide and commercial bleaching earth had the same effect on red color reduction. Yellow color in the oil samples treated with commercial bleaching earth, adsorbent consisting of 90% commercial bleaching earth - 10% aluminum oxide, and adsorbent containing 95% commercial bleaching earth - 5% magnesium oxide was reduced and reached to 38, 50 and 50 Lovibond, respectively as compared to the control sample with yellow color of 70.00 Lovibond. Copper and iron decreased 100% by using adsorbents containing 50% commercial bleaching earth and 50% aluminum oxide or 50% commercial bleaching earth and 50% magnesium oxide.According to our findings, the addition of aluminum and magnesium oxides to commercial bleaching earth was effective in reduction of peroxide value, acid value, chlorophyll, carotenoid, red and yellow color, copper and iron. Also, the results showed that the best adsorbent contain about 50% aluminum and magnesium oxides. Aluminum and magnesium oxides can improve the performance of bleaching earths.

    Keywords: Aluminum oxide, Bleaching, Magnesium oxide, Soybean oil, Bleaching earth
  • Raza Bataghva, Ahmad Ehtiati, Masomeh mehraban* Pages 555-568
    Introduction

    Hypertension is the result of angiotensin converting enzyme (ACE) activity in the vessel wall membrane. This enzyme converts angiotensin I to angiotensin II which results in vessel wall stiffness and an increase in blood pressure. Inhibition of ACE activity is a therapy for hypertension. In addition to synthetic inhibitors, some bioactive peptides (which are the products of protein proteolysis) have been identified as ACE inhibitors. Bread is a widely consumed bakery product all over the world. During dough fermentation, yeast proteases hydrolyze wheat flour proteins to prepare amino acid for cell growth. Natural cereal proteases are considered to be the other sources of protease. Proteolysis produces peptides in dough, which are bake-stable and have physiological effects on human body. Soy protein is a valuable plant protein, reported to be a source of peptides with ACE inhibitory activity and can be used to induce diversity in peptide species during dough fermentation. In this study, a completely randomized factorial design was created to evaluate the effect of the type of soy protein derivative, wheat flour substitution level and fermentation time on the ACE inhibitory activity of dough bioactive peptides.

    Materials and Methods

    Wheat flour was substituted with 3 soy protein derivatives, including soy protein isolate, extruded soy protein and soy protein hydrolysate at 5 and 10%. Moreover, fermentation time was adjusted at 30, 60 and 90 min. Dough aqueous extract was evaluated in terms of molecular weight distribution using SDS-PAGE technique. The extract was then filtered through 3KDa membrane to separate short-chain peptides (theoretically <30 amino acids). Peptide concentration was determined using UV absorbance difference. The peptide solution was tested for the degree of hydrolysis based on OPA complexation reaction and ACE inhibition activity using FAPGG as the reaction substrate at two peptide concentrations. The experiments were triplicated and data were analyzed by ANOVA and Fisher`s mean comparison test using MINITAB software.

    Results and Discussion

    Based on the SDS-PAGE pattern, it was observed that samples had a high level of low molecular weight peptides fraction were those enhanced with extruded soy proteins and soy protein hydrolysate. This results indicated that the addition of soy protein derivatives led to a higher content of short-chain peptides compared with wheat dough.  The results also showed that all the examined variables, i.e. the type of protein, substitution degree and fermentation time, significantly affected the degree of hydrolysis and ACE inhibition activity of the separated peptides. The maximum degree of hydrolysis was observed in samples with soy protein hydrolysate- which was expected to have greater peptides diversity. This might be the reason for the higher ACE inhibition activity observed for these samples. Addition of Soy protein extrudate resulted in a higher degree of hydrolysis compared with soy protein isolate revealing that the extrusion technique caused to increase the protein susceptibility to proteolysis during fermentation along with the higher content of broken amino acid chains. The higher wheat flour substitution level resulted in a higher degree of hydrolysis, while in the case of ACE inhibitory activity, it was not significant.  Overall, longer fermentation time increase the degree of hydrolysis, but led to lower ACE inhibition activity, probably due to active peptides hydrolysis. Wheat flour itself had a high level of ACE inhibition activity at the shortest fermentation time, compared with composite flours, while this activity was reduced at extended fermentation time. IC50 was the highest for the samples containing soy protein hydrolysate, surely a benefit from the initial proteolysis. In conclusion, the wheat flour substitution with 5% soy protein hydrolysate substitution,would lead to reasonable ACE inhibition activity and is suggested for bread formulation with hypertension lowering effect. It also needs more research to be done in order to evaluate substitution degrees lower than 5%, because it was observed that peptides diversity was more important than high hydrolysis degree. Overall, soy protein extrusion enhanced proteolysis and short-chain peptides production during fermentation which is a better option compared with isolated soy protein.

    Keywords: Angiotensin Converting Enzyme, Bread, hydrolysate, Soy protein extrudate, Soy protein isolate
  • Mazdak Alimi*, Ali Motamedzadegan, Shirin Shokoohi Pages 569-580
    Introduction

    In recent years, legumes have been highly considered as a good source of protein, fibers, minerals and other bioactive compounds in order to develop novel foods with improved nutritional properties. There is some evidence that legume consumption reduces the risk of diabetes, cardiovascular disease and some cancers. Vicia faba has about twice protein content as cereals and can be a good alternative to meat and protein-rich ingredients. It should also be noted that the amount of insoluble fiber is higher than soluble fibers in legume. Vicia faba belongs to the Fabaceae family .Vicia faba contains high protein (21-41% dry content of the bean), carbohydrates (51-68% dry content of the bean), fiber (5-5.8%), B-vitamins and minerals. Recently, the protein function of Vicia faba, especially its protein isolate, has been studied on a laboratory scale for use in food products, due to its good ability in hydration, solubility, emulsification, viscosity, and foam and gel formation. Research has also shown that the protein in Vicia faba has better ability to emulsify water and oil and foaming capacity and foam stability compared to bean and pea flour. The structural and functional properties of the protein isolates and concentrates of legumes such as Vicia faba are strongly influenced by their preparation, extraction and drying methods. One of the ways to improve extraction and optimization of protein properties can be ultrasound and an enzymatic controlled hydrolysis. Due to the importance of dietary fiber, various methods have been developed for their decomposition, many of which are very precise and special, some of which have high-purity enzymes and selectively release oligosaccharides and polysaccharides containing dietary fiber. In this  study, the possibility of using ultrasound and limited enzymatic hydrolysis in order to produce value added product and increase the extraction efficiency and improve the functional properties of protein and fiber of Vicia faba, were evaluated.

    Materials and Methods

    In this study, ultrasound and enzymatic hydrolysis were used to optimize extraction and modify physicochemical properties of protein and fiber of VaciaFaba. The proteins were affected by ultrasound at 200, 300 and 400 W for 15, 25 and 35 minutes, and the Alcalase enzyme 2.4 LFG at 0.15, 0.3 and 0.45% doses were extracted at 15, 25 and 35 minutes and the design of the treatments was done by Designer Express software. Solubility, oil absorption capacity, emulsification and zeta potential of protein samples were measured. Vicia faba fiber extraction under alkaline conditions was obtained from solutions of 0.0012, 0.012 and 0.12% sodium hydroxide until reaching pH 12, 11 and 10 and Termamy 2x enzyme was used for enzyme hydrolysis. Water retention capacity and rheological properties of Vicia Faba fiber samples were investigated.

    Results and Discussion

    The results showed that the use of ultrasound and enzymatic hydrolysis had a positive effect on solubility, oil absorption capacity and emulsion properties of the protein samples. Zeta potential was also negative for all treatments, which indicates that the Vicia faba protein treatment solution contains more negative amino acids than positive-loaded amino acids. Among the fiber samples of the ViciaFaba, a fiber sample with a pH of 10 had the highest water retention capacity and G-level than the other two samples, indicating a more solid and elastic quality. Also, in all fiber samples, increasing cutting speed reduced the viscosity and the samples showed a dilution action with cutting or pseudoplastic.

    Keywords: Viciafaba, extraction, protein, fiber
  • Mahyar Rad*, Hamed Ghafori, Zohreh Gholami Pages 581-605
    Introduction

    Edible mushrooms are among the most perishable products that begin to lose quality immediately after harvest, and the short shelf-life of these products will cause problems when it comes to the marketing and distribution of these products in a fresh form. Edible coatings are a good tool for prolonging the useful life of foods and increasing their quality without contaminating the environment.

    Materials and Methods

    In this study, the possibility of increasing the shelf-life of a button mushroom using blanching followed by coating with carboxymethyl cellulose and sodium metabisulfite was studied. Independent variables included concentrations of carboxymethyl cellulose and sodium metabisulfite (0-2%) and storage time up to 16 days at 4 ° C. This experiment was designed on the basis of three-level factors consisting of 6 central points after 0, 4, 8 and 16 days of storage at 4°C. Factors determined on a button mushrooms included pH measurements, weight loss percentage, soluble solids, texture, color, browning level, total microorganisms count as well as mold and yeast count.

    Results & Discussion

    The results of this study indicated that the sample coated with 2% carboxymethyl cellulose and 2% sodium metabisulfite resulted in an increase in pH level as well as soluble solids. In addition, the slightest color change, weight loss and reduction in tissue stiffness were observed in this sample. The sample coated with 2% carboxymethyl cellulose with 2% sodium metabisulfite had also the lowest total microorganisms count and the count of mold and yeast stored at 4 ° C after 16 days. Based on the results of this study, carboxymethyl cellulose and sodium metabisulfite coatings can be used as an appropriate coating agents for the preservation of organoleptic, chemical, microbial properties and shelf-life of button mushrooms.

    Keywords: button mushroom, carboxymethyl cellulose, Edible coating, shelf-life, sodium metabisulfite
  • Mehran Aalami*, Bahareh Fathi Pages 607-619
    Introduction

    Millet is one of the cereals resistant to drought, pest and disease and has a short growing season. As the world's population grows and water resources decline, this agricultural product will increasingly become- important for human use in the future. Millet is gluten-free grain and can be used to produce special food for celiac patients. Due to the low quality of baking products made from gluten-free cereals, additives and physical treatment of flour can be used to improve the baking properties. Therefore, in the present study, heat-moisture treatment of millet grains was used as a method to modify the flour properties.

    Materials and Method

    Proso millet (Panicum miliaceum L.) was dehulled using a stone mill and then moistened to 20, 25 or 30% of moisture by spraying sufficient distilled water, mixing and keeping in polyethylene bags at 4°C overnight. The moistened grains were poured into glass containers and heated in an oven at various temperatures (100 or 120 ° C) for 3 h. After heating, the samples were removed from the containers and dried at about 40°C until about 9% moisture content. The samples were then milled and passed from the screen with standard mesh 80. In this study, cakes were prepared from untreated and treated millet grain. The specific gravity of batter was measured by dividing the weight of a specific volume of batter to the weight of the similar volume of water. Batter viscosity was determined by Brookfield viscometer. Cake volume was measured by the rapeseed displacement method. Color of cake crumb and crust were determined by scanner and image J software. The oven method was used for measuring cake moisture. The hardness of cakes was evaluated by texture profile analyzer. For study of the microstructure of cakes, scanning electron microscope (Hitachi) was applied. In this study, the effects of two factors including moisture of heat-moisture treatment (at 3 different levels) and temperature of heating (at 2 different levels) on the batter and cakes properties were studied by a completely randomized design. Statistical analyses were done via analysis of variance (ANOVA) and Duncan’s multiple range tests for significance at p<0.05 using SAS 9.1 software.

    Results and discussion

    The low specific gravity shows the better aeration of cake batter which can result in greater cake volume. Heat-moisture treatment of millet grains reduced the specific gravity of the cake batter so that the specific gravity of the untreated millet flour batter was the highest. The low batter viscosity reduces the cake volume because the batter cannot keep trapped air bubbles inside it and when the batter is placed in the oven, these bubbles move up to the surface of batter and they get out of the cake. However, a very viscous batter also cannot produce high volume cakes due to the limited expansion of the batter. Therefore, the optimum and appropriate viscosity of the batter is necessary for the production of large volume cakes. Heat-moisture treatment of millet grains significantly increased the viscosity of the batter (p<0.05) so that the lowest viscosity was in the control sample and the highest viscosity was in the treated sample at 30% moisture and 120°C. The samples treated at lower moisture and temperature had higher cake volume compared to the control sample, while the treated samples at higher moisture and temperature showed no improvement in volume. Millet flour treated at 30% moisture and 120°C significantly reduced cake volume (p<0.05) and this effect may be due to excessive viscosity of the batter which prevents the batter expansion in the oven. Increasing the treatment temperature and moisture significantly increased the darkness and redness of the cake color. However, at the baking day and during storage, there was no improvement in the texture and moisture content of the cake crumb after heat-moisture treatment of millet grains. The scanning electron micrographs of raw and treated millet cake showed that heat-moisture treatment of grains increased the uniform and fine cavities in the cake texture. Furthermore, in the cake prepared from treated millet, the gelatinized starch granules are found in the greater numbers.The development of gluten-free bakery products has a growing market worldwide. Therefore, food industry specialists are looking for the production and improvement of the quality of these products. Due to the increasing consumer demand for non-additive foods, there is a growing interest in the physical treatment of cereals as it changes the starch performance without the addition of external ingredients. In this regard, the results of the present study revealed the ability of heat-moisture treatment to modify the performance of millet flour for application in gluten-free product formulations by improving their qualitative properties. Application of heat-moisture treated millet increased cake batter viscosity and air penetration and reduced its specific gravity. Heat-moisture treatment of millet grain at low moisture and temperature improved cake volume. However, the treatment of millet grains did not improve texture and moisture content of the cake during storage. Study of microstructure of the cakes showed that the heat-moisture treatment of millet grain increased the uniform and fine air cells in the cake structure and also the starch granules were more gelatinized. According to the results of this study, heat-moisture treatment of millet grains at 25% moisture and 100 ° C improved quality parameters of batter and cake compared with control.

    Keywords: millet grain, heat-moisture treatment, cake, gluten-free
  • Maryam Keshani, Nafiseh Zamindar*, Reza Hajian Pages 621-628
    Introductıon

    The Scombridae family of fish consists of tuna, bonito and mackerel species that are found in warm waters. Tuna species is important because of economic value and prevalence in global trade. Although, they are usually not consumed fresh because of the limited fishing season, lack of accessible markets at certain locations and cost of transport to other areas. Therefore, long-term preservation methods must be used. For many years, freezing has been the method of preserving food for a longer period without a significant quality decrease. Thawing with minimal damage to the products quality is very important. Since common thawing methods are usually slow and reduce food quality, a substituted technique seems necessary. Ohmic thawing is a thermal-electrical method with a more uniform heat compared to other thermal-electrical methods. The speed and relative uniformity of ohmic heating is possible by passing direct electrical current through the product. In this process, the electrical resistance of frozen food is utilized. Electrical energy passes through food by means of electrical current and is dissipated in the form of heat (Joule effect). Based on Ohm’s law, the amount of dissipated heat is directly related to the used voltage and the electrical conductivity of the product or its parts.

    Materials and Methods

    Muscles of the frozen tuna fish were cut into 3x3x3 cm cubes and kept in zip lock bags and stored at -30  for 24 h. Then the samples maintained at -18  until the experiments time. The ohmic cell was filled with saline solution (0.3%, 0.4% and 0.5% respectively) and the thermocouple was connected to the geometric centre of the frozen fish at -18. Then a voltage of 50 volts with 50Hz frequency was applied until the sample centre reached -7. The samples were then removed from the cells and protein solubility, pH, TVBN, centrifuge loss, thawing loss, drip loss, evaporation loss, and press juice were measured at 0, 24 and 48 h after thawing. Completely randomize design in factorial form with three replications was carried out for the experiments. Data were analyzed by SAS software.

    Results and Discussion

    In this research, ohmic thawing was evaluated as a new method for thawing fish. According to the results of ANOVA, with passing of time the protein solubility, pH, TVBN, centrifuge loss and press juice was increased. With further study of ANOVA of thawing loss and drip loss, it was concluded that salt concentration had a significant effect on dependent parameters (P<0.05). While keeping a high thawing speed, no burning marks appeared on the edges and around the samples in the ohmic method.

    Keywords: Tuna fish, Immersion ohmic thawing, TVB-N, Protein solubility
  • Maryam Sadat Sotoodeh, Nafiseh Soltanizadeh* Pages 629-641
    Introduction

    Over the last few decades, development of the industrial life has remarkably increased the demand for consumption of ready-to-eat foods. Deep fat frying is a fast and conventional method for cooking and due to creating crispy surface, soft internal texture, desired color and taste has popularity among consumers. The main problem related to fried food products is the high oil absorption during deep fat frying that is harmful for human health and has negative effects on shelf life of the product. Therefore, the aim of this study was to investigate the role of breading particles size as well as the influence of addition of soy protein isolate in breading and batter layers on properties of chicken nugget.

    Material and Methods

    First, breading was divided to three particle sizes. Sieves with mesh size 40 (0.42 mm) and 60 (0.25 mm) were used for separation of small breading. Also, sieves with mesh size of 18 (1 mm) and 20 (0.84 mm) as well as 10 (2 mm) and 12 (1.68 mm) were used for preparation of breading with medium and large particle size, respectively. Three percent soy protein isolate was separately added to breading with particle size of small, medium and large and used for production of chicken nugget. Also, 3% soy protein isolate was added to batter mixture and then nuggets coated with three different breading particle size without soy protein isolate. Breading pick-up, moisture content, cooking loss, porosity, oil absorption and penetration, color and textural properties of the chicken nuggets were then evaluated.

    Results and discussion

    Based on the results, the coating of chicken nuggets with small breading size led to the product with the highest moisture content and lowest porosity, oil uptake, oil penetration and shear force. However, chicken nuggets coated with small breading size had the highest breading loss. After incorporation of soy protein isolate to breading, the highest hardness and lowest springiness, cohesiveness and gumminess were related to the nuggets coated with small breading size, however, chewiness was not affected by breading particle size. Breading with small particle size containing soy protein isolate caused the highest L*, a* and b* values in fried chicken nuggets. Addition of soy protein isolate to breading layer significantly caused a decrease in cooking loss, porosity, oil absorption and penetration (p < 0.05). These samples had higher moisture content than the control sample. After addition of soy protein isolate to batter layer, color of chicken nugget did not considerably change (p > 0.05). The effect of soy protein isolate on textural properties is dependent on breading particles size. Generally, the addition of this compound to batter layer decreased hardness, gumminess and chewiness; however, its effect on springiness and cohesiveness is dependent on breading particle size. The presence of soy protein isolate in batter layer increased moisture content which in turn could diminish porosity, cooking loss, oil absorption, and oil penetration (p < 0.05). Overall, the comparison between chicken nugget properties when soy protein isolate was added to breading or batter layer indicated that the presence of the protein in breading layer was more effective in retention of moisture, reducing of cooking loss, porosity, oil absorption and oil penetration. However, these samples had more hardness, gumminess and chewiness compared to those containing soy protein isolate in batter layer. Cohesiveness of chicken nugget containing soy protein isolate in breading was not significantly different with those produced with the compound in batter layer.
    The production of chicken nugget with small breading size containing 3% soy protein isolate in batter layer was proposed for production of products with better nutritional and physicochemical properties.

    Keywords: Soy protein Isolate, Chicken nugget, Breading, Batter
  • Hadi Tanavar, Hassan Barzegar*, Behrooz Alizadeh Behbahani, MohammadAmin Mehrnia Pages 643-653
    Introduction

    Free radicals activity and their products of their oxidation can cause undesired feeling and nutritional effects such as, awful taste, destroying vitamins and destruction of essential fatty acids. These compounds which are toxic substances and damage the genetic material of cells causing heart and cardio vascular diseases and different type of cancer. Antioxidats absorb free radicals, so they can decelerate oxidation speed, then delete them to save the body from undesirable effects. Pooneh which is called scientifically Mentha pulegium belongs to lamiaceae group. The aim of this study was evaluating chemical compounds, antioxidant activity, total phenolic and cytotoxicity of Mentha pulegium essential oil (MPEO) on cell line of colon and gut cancer.

    Materials and methods

    In this study, after extraction of MPEO using condensation the essential oil chemical composition were identified with gas chromatography-mass spectrometer (GC-MS). Antioxidant activity was measured with radical inhibition ability method DPPH, ABTS and also their resistance against linoleic acid oxidation and changing β-carotene color, was considered. The evaluation of total phenolic composition was carried out using folin-ciocalteu method. To do this, the concentration of 1000, 10000, 1200 and 1400 of MPEO with alcohol was prepared. One mL of each concentration was added to 2.5mL of folin-ciocalteu reagent. After 2.5 minutes, 2ml sodium carbonate was added and mixed well. The rate of sample absorbtion after one hour was 725 nm. Determination of flavonoids range was done with aluminum chloride. MPEO cytotoxicity effects (1, 3.125, 6.25, 12.5, 25, 50, 100, 200 mg/ml) on colon cancer cell line (HT29) was performed using MTT method. In this method 30 mL of MTT solution with 5 mg/mL was add to all wells and maintain for 3 hours in carbon dioxide. After removing environment, 200µl DMSO was add to each well and the rate of absorbtion in 570 nm was read usingELISA/microplate reader device. Cell aliveness curve was drawn.

    Results and discussion

    The results showed that MPEO had 25 compounds, dl-limonene 28.44%, D-carvone 18.76%, Eucalyptol 8.86% and pulegone 8.65% were the top components. The rata of Mentha pulegium free radicals control with DPPH and ABTS was 51.5% and 53.43% respectively. The amount of MPEO resistance against oxidation of linoleic acids and color changing in β-carotene was 59.22%. Total phenolic was equal to 73.35 mg gallic acid/ml. The cytotoxicity effects results showed, the percent of HT29 aliveness was 100, 70.21, 61.26, 51.98, 35.12, 24.44, 18.65 and 10.92 respectively. Based on the results, increasing in MPEO concentration, caused increasing in HT29 cell line and decreasing percentage of aliveness. The most cells toxicity was in 200 mg/mL and the less was in 1 mg/mL.
    According to the results, in this study MPEO had suitable antioxidant activity, so we can use Mentha pulegium as an alternative for synthesis preservatives in food industry.

    Keywords: Pooneh essential oil, β-carotene linoleic acid, Total flavonoids, Gas chromatography
  • Shima Nasiri, Saman Abdanan Mehdizadeh*, Mokhtar Heidari Pages 655-667
    Introduction

    Texture represents one of the four principal factors defining food/fruit quality, together with appearance, flavour and nutritional properties (Bourne, 2002), and plays a key role in consumer acceptability and recognition of quince. Textural characteristics of quinces defined by “crispness”, “juiciness”, “hardness”,“firmness” and “mealiness” are often key drivers of consumer preference. Many non-destructive methods, including image analysis, spectroscopy, ultrasound and sound techniques, have been developed to diagnose internal and external defects in fruits and vegetables. Cheng and Haugh (1994) used a frequency of 250-kHz, rather than 1-MHz, to detect hollow heart. They were not able to transmit successfully the ultrasound wave through the whole tuber using 1-MHz transducers but found the 250-kHz transducers to be practical for a transmission path length of up to 89.7 mm. In a research an acoustic setup was developed to simultaneously detect the resonant frequencies from equator and from calyx shoulder of pear. The researchers proposed index based on these two frequencies was used for firmness evaluation of non-spherical pear; Compared with two types of single frequency-based indices, the firmness sensitivity of the dual-frequency index is mostly close to that of MT penetration test. The firmness index can classify pears with a high total accuracy (93.4%), making it suitable for nondestructive detection of firmness of differently shaped pears (Zhang et al., 2018). The goal of this study was to develop a nondestructive method based on acoustic impulse response of quince fruit using genetic programming and artificial neural network during storage.

    Materials and Methods

    In the experiment 120 quince fruits (Cydonia oblonga) were harvested from a field near Isfahan 181 days after full flowering of the trees. For each cultivar, only samples of similar size and without visible external damage were chosen. The samples were packed in sterile nylon bags and stored at 4°C. Non-destructive test (acoustic response) as well as destructive test (chemical measurement and penetration test) were performed every 15 days for 4 months (Akbari Bisheh et al., 2014). Total soluble solids (TSS) were determined by a hand refractometer device (model: MT03 Japan) and expressed as °Brix. Ascorbic acid of the juice was measured by titration with copper sulfate and potassium iodide based on the Barakat et al. (1973) procedure. Titratable acidity was measured according to the AOAC method. To determine the total phenol content of juice, the Waterhouse method (2000) was used. Determination of the pH of the fruit extract using a pH meter (Portable Model P-755, Japan). Physical attributes of the samples including volume as well as major, minor, intermittent diameters and mass were calculated using the relations proposed by Stroshine and Hammand (1994). Penetration test was conducted by the material test machine (SANTAM, STM-20 model, Iran).In order to analyze the response sound signal of quince in time and frequency domain, a system equipped with a sample holder with foam rubber covered surface, an impact mechanism, a microphone and an electronic circuit was utilized. To record impact sound features a microphone was positioned next to the fruit and was hit at three speed level (0.3, 0.9 and 1.5 m/s). After recoding sound, five features (acoustic peak, maximum acoustic pressure, mean acoustic pressure and natural frequency) were extracted and used as inputs for models. In order to predict the stiffness, four methods of genetic programming, neural network and existing mathematical models (FI and SIQ-FT) were used. In order to carry out statistical analysis, analysis of variance (ANOVA) and Duncan's multiple range test at 5% probability level were performed according to the completely randomized design (CRD).

    Results and discussion

    In this study, Duncan's multiple range comparison test was used to investigate the significant difference between destructive and non-destructive parameters at 5% probability level. According to the results, acoustic peak, maximum acoustic pressure, mean acoustic pressure and natural frequency were decreased by increasing storage time. Statistical analysis of the destructive tests also showed a decreasing trend at the 5% level. In several papers, two mathematical equations have been used to obtain the relationship between the mass resonance frequency and the sound of impact. In this study, genetic programming and neural network modeling were used to compare the results of these relationships. The regression coefficients between the actual and the predicted values for the resonance-mass relation and the effect of the sound from the collision were R2= 0.601 and R2= 0.754, respectively. Also, the regression values obtained from genetic programming and neural network modeling were R2= 0.9567 and R2 = 0.933, respectively. In a research, the overall R2 value amounts for stiffness prediction was reported to be 0.79 (Schotte et al., 1999). Abbaszadeh et al. (2013) evaluated watermelons texture using their vibration responses. They declared their proposed method could predict textural acceptability of watermelons with determination coefficients 0.99. According to the obtained values, the best methods for stiffness prediction were genetic programming and f neural network methods, respectively.

    Keywords: Genetic Programming, Neural Network, Quince fruit, Storage, Stiffness
  • Forouzan Jalali zand, Mohammad Goli* Pages 669-685
    Introduction

    Microencapsulation is represented as a technology of packaging solids, liquids, or gaseous materials in miniature sealed capsules that can release their contents at controlled speeds under specific conditions. The packaged materials can be pure materials or a mix, which are also called coated material, core material, actives, internal phase (Fang & Bhandari, 2010). Selenium is a micronutrient essential element for human health, which is toxic in high concentrations. Selenium is a component of selenoproteins that plays an enzymatic and structural roles in human biochemistry. Selenium is known as an antioxidant and catalyzer for active thyroid hormone production. The aim of this study was to optimize the microencapsulation of sodium selenite (100-900 mg per 20 mL final spray solution) using a combination of Arabic gum (25-29% per 20 mL final spray solution) and Persian gum (1-5% per 20 mL final spray solution) as capsule wall applying modified solvent evaporation method to produce microcapsules with the highest encapsulation efficiency (EE) and the smallest possible particle size using the response surface method (RSM) with central composite design (α = 2 with 6 central points and 2 repetition in axial and factorial points).

    Materials and Methods

    In this research, production of encapsulated sodium selenite at different concentration (100, 300, 500, 700 and 900 mg/20 cc) with Arabic gum (25%, 26%, 27%, 28% and 29%) and  Analogous Farsi gum (5%, 4%, 3%, 2% and 1%) as wall materials by solvent evaporation method was studied. The optimization of microcapsules based on the highest encapsulation efficiency and smallest microcapsules size was studied using RSM. Based on the mentioned parameters, 2 optimum conditions were chosen. The first one was a condition where the samples produced with 135 mg sodium selenite in 20 ml sprayed solution, 27% and 3% Arabic and Farsi gum, respectively. In this condition the encapsulation efficiency was 79.63% whereas the microcapsules size was 49.98 µm.  The second condition was followed by producing samples with 109 mg sodium selenite in 20 ml sprayed solution, 28% and 2% Arabic and Farsi gum with result of 95.10% encapsulation efficiency and the size of 46.71 µm. Finally 390 ppm capsules of the first condition and 480 ppm capsules of second condition (equal to 8.6 ppm sodium selenite salt), synthesized BHA (200 ppm) and sodium selenite salt (8.6 ppm) were added to a free anti-oxidant soybean oil and were kept at 55°C at 0, 23 and 46 days which was equal with 20°C at 0, 180 and 360 days. In this condition, peroxide value, acidity, Thiobarbituric acid, Anisidine value, Totox value and anti-oxidant activity of free anti-oxidant soybean oil were evaluated using SPSS software.

    Results & Discussion

    The results achieved by RSM showed that sodium selenite concentration had reverse relation on encapsulation efficiency whereas there was direct relation with Arabic and Farsi gum concentration. Also the size of microcapsules with had direct relation on sodium selenite concentration whereas Arabic and Farsi gum concentration had reverse relation. The result of SPSS analyses showed that with presence of the encapsulated sodium selenite anti-oxidant and synthesized BHA anti-oxidant in soybean oil, peroxide value, acidity, Thiobarbituric acid, Anisidine value, Totox value decreased whereas anti-oxidant activity of soybean oil increased. Based on anti-oxidant characteristics in soybean oil, recommended treatments in this research are: condition 2 ˃ condition 1 ≥ BHA ˃ sodium selenite salt ˃ control sample without anti-oxidant. The results of this study recommend the incorporation of encapsulated sodium selenite (condition 1 and 2) for increasing the shelf life of soybean oil as an alternative to synthesized BHA.

    Keywords: Microencapsulation, Arabic-Farsi gum, Sodium selenite, Antioxidant activity, Soybean oil