فهرست مطالب

پژوهش های صنایع غذایی - سال سی‌ام شماره 2 (تابستان 1399)
  • سال سی‌ام شماره 2 (تابستان 1399)
  • تاریخ انتشار: 1399/06/01
  • تعداد عناوین: 12
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  • حبیبه اسکندرلی، سیده زهرا سیدالنگی*، زهرا غیاثوند صفحات 1-12
    زمینه مطالعاتی

    با توجه به ویژگی های نهفته در ترکیبات هیدروکلوییدی می توان با افزودن این ترکیبات به محصول سوخاری از احتمال ابتلا به عوارض ناشی از مصرف آن از جمله پر چرب بودن کاست.

    هدف

    مطالعه حاضر با هدف بررسی اثر افزودن  سطوح مختلف هیدروکلوییدهای هیدروکسی پروپیل متیل سلولز، آلژینات سدیم و کاراگینان در پوشش خوراکی بر ترکیبات شیمیایی و خصوصیات حسی میگو سوخاری انجام گردید.

    روش کار

    تیمار های استفاده شده دراین مطالعه شامل سطوح 5/0، 1 و 5/1 درصد  از هر یک از صمغ ها می باشد که به ازای هر تیمار 3 تکرار نیز در نظر گرفته شد.

    نتایج

    یافته های به دست آمده حاکی از وجود اختلاف معنی دار در بین تیمار ها بودند (05/0 (P<. با ارزیابی یافته های مربوط به نتایج ترکیبات شیمیایی می توان از تیمار های مربوط به سطوح مختلف آلژینات سدیم به عنوان تیمار های دارای بهترین عملکرد در حفظ رطوبت و کاهش چربی نام برد. پروتئین در تیمارهای کاراگینان بیشترین و در شاهد کمترین مقدار بود. به طور کلی، بر اساس نتایج ترکیبات شیمیایی و ارزیابی حسی تیمار 5/0 در صد آلژینات سدیم  مناسب ترین تیمار جهت اضافه نمودن به آرد اولیه میگوی سوخاری معرفی می گردد.

    نتیجه گیری نهایی

    نهایتا، پس از تیمار های آلژینات سدیم نتایج مربوط به تیمارهای 5/1 درصد کاراگینان و 5/0 درصد هیدروکسی پروپیل متیل سلولز به ترتیب از عملکرد مناسب و نه چندان مطلوب و قابل توجه برخوردار بودند.

    کلیدواژگان: آلژینات سدیم، ترکیبات شیمیایی، کاراگینان، میگو سوخاری، هیدروکسی پروپیل متیل سلولز
  • آرمین نبی زاده قولنجی، محمود رضازاد باری*، صابر امیری، بهروز آتشبار صفحات 13-28
    زمینه مطالعاتی

    دونالیلا سالینا یک ریزجلبک دریایی است که حاوی رنگدانه بتاکاروتن، فیکوسیانین، پلی ساکاریدها، آهن و روی می باشد.

    روش کار

    در این تحقیق اثر نسبت های مختلف آب پنیر و محیط کشت والنه جهت تولید بیومس دونالیلا سالینا و ارزیابی خصوصیات بیوشیمیایی شامل ترکیبات فنلی کل، فلاونویید کل، قندهای محلول  و فعالیت آنتی اکسیدانی مورد مطالعه قرار گرفت. بدین منظور سه فاکتور شامل غلظت محیط کشت والنه (صفر، 25 و 50 میکرولیتر)، درصد آب پنیر (صفر، 5/2 و 5 درصد) و مدت زمان گرمخانه گذاری (صفر، 7 و 14 روز) در قالب طرحBox-Behnken  با 17 نمونه مورد مطالعه قرار گرفت.

    نتایج

    نتایج نشان داد که با افزایش درصد آب پنیر و همچنین محیط کشت والنه، تراکم سلولی و مقدار فلاونویید افزایش یافت، که این افزایش معنی دار بود (05/0<P). نتایج نشان داد که زمان گرمخانه گذاری بر میزان تراکم سلولی، فعالیت آنتی اکسیدانی و قند محلول اثر معنی داری داشت (05/0<P)، به طوری که با افزایش زمان گرمخانه گذاری، تراکم سلولی، فعالیت آنتی اکسیدانی، قند محلول و فلاونویید کاهش یافت. همچنین با افزایش درصد آب پنیر و زمان گرمخانه گذاری مقدار قند محلول در روزهای پایانی گرمخانه گذاری کاهش معنی داری داشت (05/0<P). با افزایش درصد آب پنیر مقدار فنل کل کاهش معنی داری نداشت و مقدار قند محلول ثابت ماند (05/0<P). با افزایش غلظت محیط کشت والنه و زمان گرمخانه گذاری، میزان فعالیت آنتی اکسیدانی و قند محلول کاهش معنی داری داشت (05/0<P). شرایط بهینه در روز 5 گرمخانه گذاری، 5 % آب پنیر و صفر درصد محیط کشت والنه بدست آمد.

    نتیجه گیری نهایی

    بر اساس نتایج حاصل از این پژوهش، استفاده از آب پنیر بعنوان محیط کشت جهت کشت ریزجلبک دونالیلا سالینا موفقیت آمیز بوده است.

    کلیدواژگان: دونالیلا سالینا، تولید بیومس، آب پنیر، کشت
  • زهره دیدار * صفحات 29-40
    زمینه مطالعاتی

    بادکردگی دوغ ناشی از فعالیت مخمرها یکی از معایب عمده این محصول به حساب می آید. مخمر کلویورومایسسمارکسیانوس یکی از مهم ترین عوامل فساد دوغ و عامل بادکردگی محصول است.

    هدف

    در این تحقیق اثر عملیات میدان الکتریکی پالسی بر مخمر کلویورومایسسمارکسیانوس در دوغ بررسی شده است.

    روش کار

    بدین منظور ابتدا نمونه های دوغ توسط مخمر کلویورومایسسمارکسیانوس با جمعیت تقریبی 105 سلول در هر میلی لیتر تلقیح گردید و سپس تحت عملیات میدان الکتریکی پالسی شامل  شدت میدان الکتریکی 1، 2، 3و 4 کیلو ولت در سانتی متر و تعداد پالس  50، 100، 150، 200و 250 قرار گرفت. سپس به منظور بررسی جمعیت باقی مانده مخمر از روش کشت میکروبی استفاده گردید.  اثر عملیات میدان الکتریکی پالسی بر روی  رفتار ریولوژیکی، ویسکوزیته و درصد دوفاز شدن دوغ نیز مورد بررسی قرار گرفت. بررسی مورفولوژیکی سلول های مخمر قبل و بعد از اعمال عملیات میدان الکتریکی پالسی با استفاده از میکروسکوپ روبشی با بزرگنمایی 15000-5000 انجام شد.

    نتایج

    بررسی ها نشان داد عملیات میدان الکتریکی پالسی سبب کاهش جمعیت مخمر در نمونه های دوغ گردید (p<0/05). بیشترین کاهش در تیمار فرآوری شده با عملیات میدان الکتریکی پالسی با شدت میدان الکتریکی kv/cm4 و تعداد پالس 100-250 مشاهده گردید. عملیات میدان الکتریکی پالسی سبب کاهش میزان ویسکوزیته گردید و درصد دوفاز شدن نمونه های دوغ تحت این عملیات افزایش نشان داد (p<0/05). نتایج بررسی مورفولوژیکی، نشان داد عملیات میدان الکتریکی پالسی سبب تغییراتی در مورفولوژی سلول مخمر شده است.

    نتیجه گیری نهایی

    عملیات میدان الکتریکی پالسی سبب کاهش جمعیت مخمر کلویورومایسسمارکسیانوس که عامل مهم بادکردگی و فساد دوغ است، می گردد.

    کلیدواژگان: دوغ، مخمر کلویورومایسس مارکسیانوس، عملیات میدان الکتریکی پالسی
  • عماد یوسفی، لیلا ناطقی*، نازنین زند صفحات 41-55
    زمینه مطالعاتی

    رنگ ها برای ایجاد تنوع و افزایش جذابیت در مواد غذایی استفاده می شوند. رنگ دانه گلبرگ گل گاوزبان علاوه بر رنگ دانه طبیعی حاوی ترکیبات فراسودمند مانند آنتوسیانین ها و پلی‎فنل ها هستند.

    هدف

    این تحقیق به منظور بررسی خصوصیات فیزیکی شیمیایی نوشیدنی فراسودمند بر پایه آب آلویه ورا و آب‎سیب حاوی رنگ دانه استخراج ‎شده از گلبرگ گل گاوزبان انجام شد.

    روش کار

    بدین منظور رنگ دانه از گلبرگ گل گاوزبان استخراج شد و به دو نوع نوشیدنی آب آلویه ورا و آب سیب با غلظت‎های 5 و 10 درصد وزنی/حجمی اضافه شد و نوشیدنی های تهیه شده در دو دمای 4 و oC25 طی 15 روز نگهداری شدند؛ بنابراین هشت تیمار مطابق با طرح کاملا تصادفی طراحی گردید و آزمون های pH، اسیدیته، محتوای ترکیبات پلی فنل، مقدار آنتوسیانین، شاخص تخریب آنتوسیانین و هیدروکسی‏متیل‎فورفورال روی تیمارها انجام گرفت.

    نتایج

    پس از 15 روز نگهداری، بالاترین میزان pH و پایین ترین میزان اسیدیته در نوشیدنی های آب سیب حاوی 10 درصد وزنی/حجمی رنگ دانه و نگهداری شده در دمای oC4 مشاهده شد. لازم به ذکر است نمونه مذکور بالاترین میزان ترکیبات پلی فنلی و مقدارآنتوسیانین را داشت. مطابق با نتایج افزایش دما و زمان نگهداری و غلظت رنگ دانه موجب افزایش شاخص تخریب آنتوسیانین و میزان هیدروکسی متیل فورفورال شد و در شرایط مشابه نوشیدنی های حاوی آب آلویه ورا شاخص تخریب آنتوسیانین و هیدروکسی متیل فورفورال بالاتری نسبت به نوشیدنی های حاوی آب سیب داشتند.

    نتیجه گیری نهایی

    نوشیدنی آب سیب نگهداری شده در دمای oC4 و حاوی 10 درصد وزنی/حجمی رنگ دانه به علت داشتن ترکیبات آنتوسیانینی و پلی فنلی بالاتر، به عنوان تیمار برتر از نظر سلامت بخشی انتخاب گردید.

    کلیدواژگان: آب سیب، آب آلوئه ورا، آنتوسیانین، گل گاوزبان، نوشیدنی فراسودمند
  • هدی قدیری، امان محمد ضیائی فر*، محمد قربانی، سارا آقاجان زاده سورکی صفحات 57-68
    زمینه مطالعاتی

    جهت پوست گیری گوجه فرنگی معمولا از دو روش بخار و قلیا استفاده می شود که به ترتیب با مصرف انرژی بالا و بروز مشکلات زیست محیطی همراه می باشند.

    هدف

    هدف از این پژوهش استفاده از سیستم اهمیک در پوست گیری گوجه فرنگی به منظور تعیین شرایط بهینه، کاهش زمان فرایند پوست گیری و افزایش کیفیت محصول نهایی است.

    روش کار

    جهت پوست گیری گوجه فرنگی از سیستم اهمیک استفاده و تاثیر میدان الکتریکی (محدوده 1500 تا 4500 ولت بر متر) و غلظت محلول نمکی (محدوده 1/0 تا 3/0 درصد وزنی/حجمی) بر پوست گیری گوجه فرنگی بررسی شد. پوست گیری با آب داغ در دمای C° 100 به عنوان تیمار شاهد در نظر گرفته شد.

    نتایج

    نتایج نشان داد که پوست گیری به روش اهمیک نسبت به روش شاهد موجب ترک خوردن سریع تر پوست (82 ثانیه در مقابل 523 ثانیه)، افت کمتر وزن محصول (%7/10 در مقابل %08/16) و شدت حرارت دهی کمتر (C° 22/33 در مقابل C° 02/40 در نقطه سرد در انتهای فرایند) می شود. همچنین این روش باعث حفظ بیشتر محتوای اسید اسکوربیک (18/40 در مقابل 08/36 میلی گرم در 100میلی لیتر) و حفظ بیشتر سفتی بافت (47/19 در مقابل 86/30 درصد فشردگی) نمونه ها شد.

    نتیجه گیری نهایی

    استفاده از غلظت 2/0 درصد وزنی/حجمی محلول نمکی به همراه شدت میدان الکتریکی 2500 ولت بر متر به عنوان شرایط بهینه در پوست گیری گوجه فرنگی تعیین شد.

    کلیدواژگان: بهینه سازی، پوست گیری اهمیک، ویژگی های فیزیکی شیمیایی، گوجه فرنگی
  • محبوبه پیروانی، مانیا صالحی فر*، نادر کریمیان خسروشاهی صفحات 69-86
    زمینه مطالعاتی

    بیماران سلیاکی باید از مصرف محصولات دارای گلوتن اجتناب کنند. پس، برنامه ریزی برای تولید فرآورده های فاقد گلوتن و همچنین بهبود آن ها، از اهمیت ویژه ای برخوردار است. لوپین گیاهی از خانواده حبوبات است که به علت داشتن محتوای پروتئینی بالا، علاوه بر اینکه ارزش تغذیه ای محصول را افزایش می دهد تاثیرات مثبتی بر حفظ رطوبت، بهبود بافت، افزایش ماندگاری و آرومای محصول می شود.

    هدف

    در این پژوهش تاثیر آرد لوپین به عنوان منبع غنی از پروتئین و فیبر رژیمی بر ویژگی های کیک بدون گلوتن بررسی شد.

    روش کار

    در این مطالعه، با استفاده از نرم افزار Design-Expert و طرحCombined D-optimal Design ، 20 فرمولاسیون تولید شد و اثر آرد لوپین در سطوح 5، 10 و 15 %، نشاسته ذرت در  سطوح 85، 90 و 95 %، صمغ های گوار و کاراگینان هر کدام در سطوح 1، 5/1 و 2 % بر ویسکوزیته خمیر، بافت و ویژگی های ارگانولپتیکی کیک بررسی شد.

    نتایج

    نتایج سنجش ویسکوزیته نشان داد که آرد لوپین به علت فاقد گلوتن بودن، سبب کاهش ویسکوزیته و صمغ های گوار و کاراگینان با جذب آب، سبب افزایش ویسکوزیته شدند. بررسی آزمون بافت سنجی نشان داد که آرد لوپین و صمغ های گوار و کاراگینان باعث کاهش سختی بافت کیک شدند. نتایج ارزیابی های حسی نیز نشان داد که آرد لوپین و صمغ گوار سبب بهبود این ویژگی ها شدند اما صمغ کاراگینان در بهبود این ویژگی ها اثرگذار نبود. نتیجه گیری نهایی: با توجه به نتایج بدست آمده، فرمولاسیون با 15 % آرد لوپین، 85 % نشاسته ذرت، 1 % گوار و 1 % کاراگینان، دارای ویسکوزیته ای مناسب و بافتی نرم تر و مورد قبول تر بود و بیشترین امتیاز پذیرش کلی گرفت و به عنوان فرمولاسیون بهینه انتخاب گردید.

    کلیدواژگان: آرد لوپین، سلیاک، کیک بدون گلوتن، نشاسته ذرت
  • خالد عرب، بابک قنبرزاده*، شفق کریمی صفحات 87-99
    زمینه مطالعاتی

    در این تحقیق فیلم های امولسیونی بر پایه کربوکسی متیل سلولز (CMC) حاوی غلظت های مختلف نانو ذرات نقره (5/0، 1، 2% بر پایه CMC) به روش قالب ریزی تهیه شدند.

    هدف

    یکی از مهمترین اهداف این پژوهش استفاده همزمان از نانو ذرات نقره و اسید اولییک جهت امولسیون کردن فیلم ها و کاهش قابل توجه قطبیت آنها می باشد.

    روش کار

    به منظور بررسی نحوه پراکنده گی نانو ذرات در ماتریکس بیوپلیمر از آزمون پراش پرتو ایکس (XRD) استفاده شد. خواص حرارتی فیلم با استفاده از دستگاه گرماسنجی پویشی افتراقی (DSC) انجام شد. میزان عبور امواج مریی و فرابنفش، نفوذپذیری نسبت به بخار آب و خواص سطحی فیلم ها نیز مورد بررسی قرار گرفت.  

    نتایج

    نتایج نشان داد نانو ذرات در بالاترین غلظت (2%) خواص کریستالی خود را نسبتا حفظ کردند. دمای انتقال شیشه ای (Tg)، در فیلم های شاهد C° 65/86 بود که با افزودن 2% نانو نقره به C° 61/83 کاهش پیدا کرد. همچنین میزان عبور امواج فرابنفش و مریی (UV-VIS) در فیلم های حاوی 2% نانو نقره کاهش معنی داری (05/0P˂) پیدا نمود. به طوریکه تقریبا 90% از امواج فرابنفش و 77% از امواج مریی را جذب نمودند. از طرفی میزان نفوذ پذیری نسبت به بخار آب (WVP) از g/m.h.Pa  8- 10×15/7 در فیلم های شاهد، به g/m.h.Pa  8- 10×62/6 در فیلم های حاوی 2% نانو نقره کاهش پیدا کرد. میزان زبری، برآمدگی و فرورفتگی فیلم های دارای 2% نقره، نسبت به فیلم خالص افزایش و یکنواختی سطح فیلم ها کاهش پیدا کرد.

    نتیجه گیری نهایی

    استفاده از غلظت 2% نانو نقره در اکثر آزمون های انجام گرفته، نتایج به مراتب بهتری نشان داد.

    کلیدواژگان: نانو نقره، فیلم کربوکسی متیل سلولز، نانوکامپوزیت های امولسیونی
  • حدیث عظیمی نژاد، رضا اسماعیل زاده کناری*، زینب رفتنی امیری صفحات 101-129
    زمینه مطالعاتی

    باجداسازی فراکسیون های فنولی آزاد و باند شده و تعیین محتوای فنولی و فعالیت آنتی اکسیدانی آن ها می توان به عنوان جایگزینی برای آنتی اکسیدان های سنتزی و یک روش پیشگیری برای کاهش اثرات منفی ناشی از استرس اکسیداتیو استفاده نمود.

    هدف

    این مطالعه باهدف استخراج ترکیبات فنولی و فلاونوییدی از برگ گیاه زوفا (Hyssopus officinalis) انجام شد. روش کار: با استفاده از اولتراسوند پروب تحت شرایط زمانی 10 و 20 دقیقه و شدت 60 و 100 وات و استفاده از حلال اتانول: آب با نسبت های (80:20) و (50:50) و جداسازی فراکسیون فنولی آزاد از عصاره ها با استفاده از حلال متانول و اولتراسوند و سپس جداسازی فراکسیون های فنولی باند شده با استفاده از حلال سود و اولتراسوند انجام گرفته است. و فعالیت آنتی اکسیدانی توسط آزمون های مهار رادیکال آزاد (DPPH) و سنجش بی رنگ شدن بتاکاروتن - لینولییک اسید و آزمون پایداری اکسایشی (OSI)، صورت گرفت.

    نتایج

    تجزیه وتحلیل آماری نشان داد که شرایط بهینه برای استخراج، مربوط به تیمار 80 درصد اتانولی شدت 100 و زمان 20 دقیقه (80-100-20) بوده که بیشترین میزان ترکیبات فنولی و فلاونوییدی و فنولی آزاد و باند شده را دارد و بهترین فعالیت آنتی اکسیدانی و پایداری اکسایشی را فراکسیون های فنولی آزاد نشان دادند.

    نتیجه گیری نهایی

    می توان نتیجه گرفت که عصاره برگ زوفا به دلیل مقادیر قابل توجه ترکیبات فنولی و فلاونوییدی دارای قدرت آنتی اکسیدانی بالا است که بین این ترکیبات و فعالیت آنتی اکسیدانی رابطه مستقیم وجود دارد و فعالیت آنتی اکسیدانی فنول آزاد بیشتر از فنول باند شده است. همچنین اولتراسوند پروب می تواند یک روش مناسب برای تولید عصاره های گیاهی با فعالیت آنتی اکسیدانی بالا باشد. 

    کلیدواژگان: اولتراسوند پروب، فعالیت آنتی اکسیدانی، زوفا، ترکیبات فنولیک، فنول آزاد، فنول باند شده
  • یاسمن پورمحمد، مهدی قره خانی* صفحات 129-141
    زمینه مطالعاتی

    اخیرا، نقش سودمند آنتی اکسیدان ها مقابل بسیاری از بیماری های انسانی و فساد مواد غذایی که ناشی از فساد اکسایشی می باشد، توجه زیادی را به خود جلب کرده است. تفاله انار، بخش غیرخوراکی و از محصولات جانبی صنعت آبمیوه گیری و منبع غنی از آنتی اکسیدان های پلی فنلی است.

    هدف

    این مطالعه، با هدف فراهم نمودن زمینه، جهت بررسی اثر عصاره تفاله انار در صنایع غذایی و تولید محصولات غذایی فراسودمند، صورت گرفته است.

    روش کار

    در این پروژه، ارزیابی روش های استخراج آب زیربحرانی و غرقابی جهت تعیین ظرفیت آنتی اکسیدانی و مقدار ترکیبات فنلی عصاره تفاله انار انجام شد. متغیرهای استخراج آب زیر بحرانی، پارامترهای: دما (°C120، °C150 و °C180) و زمان (5، 15 و 25 دقیقه) بودند. در عصاره های تهیه شده، ظرفیت آنتی اکسیدانی، با روش های: آنتی اکسیدان  احیاء رادیکال آزاد (DPPH) برحسب درصد RSA و آنتی اکسیدان احیاکننده آهن (FRAP) برحسب میلی گرم آهن 2 ظرفیتی بر گرم ماده خشک، محتوای فلاونوییدی بر حسب میلی گرم کویرستین بر گرم ماده خشک و محتوای فنل کل با روش فولین- سیوکالتیو بر حسب میلی گرم گالیک اسید بر گرم ماده خشک، اندازه گیری و گزارش شد.

    نتایج

    ارزیابی دو روش غرقابی و آب زیر بحرانی نشان داد که بیشترین میزان استخراج، مربوط به روش آب زیر بحرانی بود. نتایج بررسی  تاثیر متغیرهای مورد مطالعه در استخراج آب زیر بحرانی نشان داد که با افزایش دما و زمان، میزان استخراج این ترکیبات، افزایش یافت به طوری که بیشترین استخراج در تیمار °C180 و 25 دقیقه بود.

    نتیجه گیری نهایی

    روش آب زیر بحرانی نه تنها یک فن آوری دوستار محیط زیست است، بلکه میزان استخراج ترکیبات زیست فعال را نیز افزایش داد.

    کلیدواژگان: استخراج آب زیر بحرانی، آنتی اکسیدان، تفاله انار، ترکیبات فنلی، فلاونوئید
  • هادی دهقانی خیاوی، مریم خاکباز حشمتی*، جلال دهقان نیا، حامد باغبان صفحات 143-161
    زمینه مطالعاتی

    خشک کردن یکی از رایج ترین روش های موجود برای افزایش مدت زمان ماندگاری موادغذایی به خصوص میوه ها و سبزی ها است.

    هدف

    با استفاده از خشک کردن، فعالیت آبی موادغذایی کاهش می یابد و از فساد میکروبی آن ها جلوگیری می شود.

    روش کار

    در این پژوهش اثر روش های مختلف خشک کردن (هوای داغ 45 درجه سانتی گراد و سرعت هوای 1 متر بر ثانیه، مایکروویو 540 وات، مادون قرمز 600 وات، هوای داغ 45 درجه سانتی گراد- مایکروویو 540 وات، هوای داغ 45 درجه سانتی گراد- مادون قرمز 600 وات و هوای داغ 45 درجه سانتی گراد- مایکروویو 540 وات- مادون قرمز 600 وات) بر خواص کیفی سیب زمینی (ضریب انتشار موثر رطوبت، بازجذب آب، چروکیدگی، رنگ و انرژی مصرفی) بررسی شدند.

    نتایج

    نتایج نشان داد که بیشترین میزان ضریب انتشار موثر رطوبت مربوط به روش های ترکیبی هوای داغ- مایکروویو و هوای داغ- مایکروویو- مادون قرمز می باشد. همچنین روش هوای داغ- مایکروویو بیشترین میزان بازجذب آب و روش هوای داغ- مایکروویو- مادون قرمز کمترین میزان چروکیدگی را به خود اختصاص داد. از طرفی در بین روش های مختلف خشک کردن، سیب زمینی های خشک شده با روش هوای داغ- مادون قرمز رنگ بهتری نسبت به سایر نمونه ها داشتند. به طوری که در این روش نسبت به روش های دیگر میزان تغییرات رنگ (ΔE) و میزان رنگ سبز تا قرمز (a) در پایین ترین مقدار و میزان روشنایی (L) و میزان رنگ آبی تا زرد (b) در بالاترین مقدار قرار داشتند. همچنین  کمترین انرژی مصرفی در بین روش های خشک کردن مربوط به مایکروویو 540 وات بود.

    نتیجه گیری نهایی

    در نهایت بر اساس ویژگی های بهینه کیفی به انتخاب نرم افزار Design Expert، مطلوب ترین روش خشک کردن سیب زمینی، روش هوای داغ 45 درجه سانتی گراد- مادون قرمز 600 وات انتخاب شد.

    کلیدواژگان: انرژی مصرفی، بازجذب آب، چروکیدگی، روش هیبرید، ضریب انتشار موثر رطوب
  • بهرام فتحی آچاچلویی*، فاطمه قنادی اصل، کاظم علیرضالو صفحات 163-174
    زمینه مطالعاتی

    افزودن لیکوپن به خاطر فواید سلامتی آن، می تواند برای تولید فرآورده های لبنی فرآسودمند به ویژه پنیر، استفاده شود.

    هدف

    هدف از پژوهش حاضر، تولید پنیر فراسودمند با افزودن لیکوپن می باشد.

    روش کار

    تاثیر افزودن سطوح مختلف لیکوپن (200، 400 و 600 ppm) بر ویژگی های فیزیکوشیمیایی و حسی پنیر سفید و مقایسه آن با پنیر کنترل در طول رسیدن پنیر تا 60 روز نگهداری مورد بررسی قرار گرفت.

    نتایج

    نتایج حاصل از تجزیه واریانس روی تیمارهای مختلف اندازه گیری شده نشان داد که زمان اثر معنی داری (05/0>P) بر pH داشت و در طول مدت زمان نگهداری، مقدار pH در تمام نمونه ها کاهش یافت. اندازه گیری شاخص پروتیولیز و لیپولیز نمونه های پنیر نشان داد که اثر نوع تیمار و زمان نگهداری در صفت مزبور معنی دار (05/0<P) بود. با افزودن لیکوپن مقدار پروتیولیز و لیپولیز نمونه ها در مقایسه با نمونه شاهد افزایش یافتند، بطوری که مقدار پروتیولیز و لیپولیز (به استثنای پنیر دارای لیکوپن (ppm 600) در همه نمونه ها تا روز 60 به طور معنی داری روند افزایشی داشتند (05/0>P). همچنین اندازه گیری مقدار نمک، چربی و پروتئین در طول مدت زمان رسیدن پنیر نشان داد که اثر تیمار و زمان بر مقدار این صفات نمونه های پنیر معنی دار نبود (05/0<P) .

    نتیجه گیری نهایی

    نتایج ارزیابی حسی (بافت، طعم، مزه و مقبولیت کلی) نشان داد که در روز 60 نگهداری نمونه پنیر حاوی لیکوپن به میزان ppm 400 نسبت به نمونه پنیر کنترل و سایر نمونه های پنیر دارای امتیاز بیشتری بود.

    کلیدواژگان: پنیرسفید، لیکوپن، ویژگی های فیزیکی شیمیایی و حسی
  • حسن موسیوند، محمد حجتی *، حسین جوینده، حسن برزگر، حسن زکی دیزجی صفحات 175-188
    زمینه مطالعاتی

    انرژی زیاد کیک به ترکیباتی مثل شکر ارتباط دارد. باتوجه به افزایش تمایل به مصرف غذاهای کم شکر، جایگزینی شکر در کیک از اهمیت بالایی برخوردار است 

    هدف

     هدف از این تحقیق جایگزینی شکر با پودر شیره انگور در کیک فنجانی بود. 

    روش کار

     شیره انگور توسط خشک کن پاششی به پودر تبدیل و در نسبت های مختلف (0، 25، 50، 75 و 100 درصد) با شکر جایگزین و میزان رطوبت، سفتی بافت، تخلخل، حجم، رنگ و حسی کیک طی سه هفته نگهداری ارزیابی گردید.

     نتایح

    وزن مخصوص خمیر با افزایش مقدار پودر شیره انگور افزایش یافت ولی در هر حالت کمتر از نمونه شاهد بود. با افزایش نسبت پودر شیره انگور، رطوبت افزایش داشت درحالیکه در همه نمونه ها، با گذشت زمان مقدار رطوبت کاسته شد. سفتی بافت طی نگهداری کیک افزایش یافت اما کیک های حاوی پودر جایگزین در همه روزها نرمتر از نمونه شاهد بودند. در روز آخر نمونه های حاوی 25 و 50 درصد پودر تفاوتی از نظر سفتی با هم نداشتند ولی به طور معنی داری نرمتر از نمونه شاهد بودند. با افزایش نسبت پودر تخلخل و حجم کیک ها کاهش یافتند ولی بیشترین میزان تخلخل و حجم کیک در نمونه حاوی 25 درصد پودر مشاهده شد. با افزایش مقدار پودر شیره انگور از شدت روشنایی کیک ها کاسته شد و شدت قرمزی و زردی کیک ها نیز به ترتیب افزایش و کاهش یافت. نتایج ارزیابی حسی نشان داد که جایگزینی شکر با نسبت های 25 تا 50 درصد پودر شیره انگور موجب بهبود برخی ویژگی های حسی (طعم، رنگ ظاهری، بافت، رایحه و پذیرش کلی) کیک گردید. 

    نتیجه گیری نهایی

    می توان از پودر شیره انگور تا حداکثر 25 درصد به عنوان جایگزین شکر در کیک فنجانی استفاده کرد.

    کلیدواژگان: تخلخل، حجم، سفتی، کیک، ویژگی حسی
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  • H Eskandarli, SZ Sayyed-Alangi *, Z Giasvand Pages 1-12
    Introduction

    By definition, value-added products are a set of products that are prepared from raw food using various kinds of human or mechanical processing, which are different from their raw food in terms of shape, texture, taste, and smell. The battered and breaded products are among the value-added products, which constitute a wide part of the market for ready-to-eat foods. As indicated by the volumes of international trade in these products, the taste and convenience of preparing these products are favored by most consumers (Venugopal 2006). Breaded shrimp is a product that is first fried in oil after coating (predusting, battering and coating with breadcrumbs), and then it is packaged and stored after freezing. Thus, the consumer only accomplishes the final cooking step, which includes frying in the oil. The poor adsorption of the coating at the food surface leads to a sharp drop in the quality of the product. So, the predusting step is performed to prevent this problem. Predusting involves the use of a soft and dry substance that is applied to the wet surface of the food before further coating, and it reduces the gaps between the coating and the food surface and it can be used as a good flavor carrier by adding spices to it (Albert et al., 2009). The battered and breaded products absorb oil equal to 15-30 percent of their own weight during the initial frying process. Consequently, it has caused the consumers to be concerned about their health, obesity and cardiovascular condition due to the high amount of oil in these products. These concerns can negatively affect the battered and breaded products’ marketing (Venugopal 2006). The ability to form hydrocolloid gels, along with their natural hydrophilic properties, enables them to prevent the absorption of oil into battered and breaded products (Fiszman and Salvador 2003; Sanz et al., 2004; Akdeniz et al., 2006; Chen et al., 2008). For example, Pawar et al. (2014) evaluated effects of hydrocolloids including HPMC, carboxymethyl celluloses and xanthan on the oil uptake of kachori in deep frying. Due to the importance of reducing oil absorption and maintaining the quality of breaded products in public health, this study has examined the effect of sodium alginate, carrageenan and hydroxypropyl methylcellulose hydrocolloids in the composition of predust of breaded shrimp on chemical compounds and sensory characteristics.

    Materials and methods

    To prepare the breaded shrimp, the frozen shrimps were taken out of the freezer, two hours before being used and defrosting was performed in the air. Wheat flour was used in the initial predusting phase. The batter was prepared according to the formula of Fiszman and Salvador (2003), which contains 75% wheat flour, 24.5% corn flour, and 0.5% salt. The dry ingredients and water were mixed in a ratio of 1 to 1.4 for 3 min by using a blender and the breadcrumbs were used for making them breading. To prepare the breaded shrimp, the samples were first predusted and then battered in each treatment, and after dripping the extra batter for 30 seconds, they were ultimately coated with breadcrumbs. Once the coating was accomplished, the samples were fried in sunflower oil in a fryer at 190 ºC for 30 seconds by using a deep frying method so as to keep the product in shape. Then, in order to remove the extra oil, the samples were suspended for 2 minutes, and after cooling the samples to the ambient temperature, the replicates of each separate treatment were packed in zip lock packages and stored in a freezer at -20 ºC until the experiments were performed. After frying of each treatment, the oil was changed and the inner frying pan was washed and completely dried to fry the next repetition. All experiments were performed in 3 repetitions. 10 different treatments, including replacement of 0.5, 1, and 1.5% of hydrocolloids with the initial amount of wheat flour in the batter formulation were prepared. AOAC (2000) method was used to measure the moisture and ash. The amount of protein and fat was also calculated by using Parvaneh method (1377).  The sensory assessment, including color, odor, taste, texture, appearance, and overall acceptance, were applied by 10 trained examiners (students of the food industry within the age range of 20-23). For sensory evaluation, a five-point hydraulic system (5: very good, 4: good, 3: medium, 2: bad, 1: very bad) was used. The examiners were asked to rinse their mouths with water after eating each sample. Means were compared with an analysis of variance (ANOVA) followed by Duncan test to determine among means at p≤ 0.05 level.

    Results and discussion

    The findings indicated a significant difference between the treatments (P<0.05). By evaluating the findings related to the results of chemical compounds (moisture, ash, fat and protein), the treatments associated with various levels of sodium alginate can be considered as treatments that have the best performance in maintaining moisture and reducing fat. Protein in the samples containing carrageenan had the highest value and the control had the lowest value. Also, the highest and lowest ash levels were belonged to different levels of sodium alginate and carrageenan, respectively. Evaluation of sensory indices (odor, taste, shape, texture, color, and overall acceptance) indicated that there was no significant difference between treatments (P<0.05).

    Conclusion

    In general, according to the results of chemical compounds and sensory evaluation of the treatment, 0.5% sodium alginate is presented as the most suitable treatment for adding to the predust of breaded shrimp. In the end, after sodium alginate treatments, the results of 1.5% carrageenan and 0.5% hydroxypropyl methylcellulose had proper and not very good and significant performance, respectively.

    Keywords: Sodium alginate, Chemical composition, Carrageenan, Hydroxypropyl methylcellulose, Breaded shrimp
  • A Nabizadeh, M Rezazad Bari *, S Amiri, B Atashbar Pages 13-28
    Introduction

    Microalgae are considered to be functional foods due to their unique bioactive compounds. Dunaliella salina is a single-celled green alga that lives in coastal waters, brackish waters, and rocky parts of ocean waters. This marine microalga contains beta-carotene pigment, phycocyanin, polysaccharides, iron, and zinc. Dunaliella salina is most important because of its high ability to collect various levels of beta-carotene. Beta-carotene of Dunaliella salina is currently widely used in the food and pharmaceutical industries. Feeding alkaline algae due to the presence of vitamins C and E and large amounts of beta-carotene increase the activity of complement and lysozyme, and ultimately increases the body's immune system. Also, the high level of protein and its usability has made algae a valuable source of protein. The price of the cultivation medium is one of the important factors affecting the final price of the biotechnological product. Whey is used as a culture medium for the cultivation of microorganisms, such as bacteria and algae, due to water-soluble proteins, minerals, organic acids, and vitamins. Regarding the high cost of culture medium used for microalgae cultivation, the aim of this study was to determine the feasibility of Dunaliella salina microalgae cultivation in whey as a cultivation medium and to study its biomass production.

    Material and methods

    In this research, the effect of different ratios of whey and Walne medium on the biomass production of Dunaliella salina and biochemical properties including total phenolic compounds, total flavonoid, soluble sugars and antioxidant activity were studied. For this purpose, three factors including the concentration of Walne medium (0, 25 and 50 μl), whey (0, 2.5 and 5%), and incubation time (0, 7 and 14 days) were studied using the response surface methodology in a Box-Behnken design with 17 samples. After collecting the data, a second-order model was used for fitting and regression analysis at α = 0.05. Finally, the optimal conditions were determined using numerical optimization and based on the desirability function. Statistical analysis was done with Design-Expert 17. For the cultivation of Dunaliella salina microalgae, 20 ml of algal suspension was added to 100 ml of mixed medium with various concentrations of Walne medium and whey in a sterile condition. The pH of the culture medium was adjusted to 5.7 by 6N HCl and NaOH. In order to create an ideal growth condition, the salinity of the culture medium was constant. The incubation temperature was 25◦C and light intensity was 2500 lux. The samples were kept in the same conditions for 14 days and the air pump was used to prepare aerobic condition for the samples.

    Results and discussion

    The results showed that with increasing whey content as well as Walne medium, cell density and flavonoids increased, which it was statistically significant (P<0.05). The results showed that the incubation time had a significant effect on cell density, antioxidant activity and soluble sugar (P<0.05), and cell density, antioxidant activity, soluble sugar, and amount of flavonoid decreased by increasing the incubation time. Also by increasing the percentage of whey and incubation time, the amount of soluble sugar decreased significantly at the end of incubation time (P<0.05). With increasing whey, total phenol content was not significantly decreased and soluble sugar content remained constant (P<0.05). By increasing the concentration of Walne medium and the incubation time, the antioxidant activity and soluble sugar decreased significantly (P<0.05). Minerals of whey such as calcium, phosphorus, magnesium, zinc, sodium and potassium are present in some of the chemical compounds of the Walne medium. As well as, whey contains a variety of water-soluble vitamins such as vitamins B12, B6, B5, B2, Acid folic acid and ascorbic acid which are essential to grow of Dunaliella salina and caused to increase its cell density. Sala et al. (2016) investigated the effect of whey protein concentrate on Spirulina platensis algae, and concluded that the use of whey protein concentrates in algae cultivation media increased the cell density (biomass) of Spirulina platensis. Generally, the changes in the antioxidant activity of Dunaliella salina cells depend on the concentration of nitrogen and NaCl sources. Also, the antioxidant level in Dunaliella salina increases with low nitrogen levels and high NaCl concentration and high light intensity. Therefore, due to the low nitrogen sources in this study, the antioxidant activity was decreased. Most algae increase the production of phenolic compounds under the environmental stress. Since this research has tried to minimize the environmental stresses in Dunaliella salina cultivation medium, it has reduced the production of phenolic compounds. Also, because phenolic compounds are produced at low temperatures, and the applied temperature to the growth of Dunaliella salina in this study was high which caused to reduce the amount of phenolic compounds. According to the literature, dilution of nutrients in Zarrouk medium and the addition of whey protein concentrate with high levels of lactose and low level of phosphorus, potassium and iron increase carbohydrate production in Spirulina platensis. So, the nitrogen concentration in the cultivation medium is a main factor that affecting the accumulation of carbohydrates in microalgae.

    Conclusion

    The optimum conditions were obtained at day 5 of incubation time, 5% whey and 0% of Walne medium. Based on the results of this study, the use of whey as a medium for cultivating Dunaliella salina microalgae has been successful.

    Keywords: Dunaliella salina, Biomass production, Whey, Cultivation
  • Z Didar * Pages 29-40
    Introduction

    Swelling is one of the main disadvantages of Doogh (Iranian yoghurt drink).  Kluyveromyces marxianus is the main cause of Doogh spoilage and its swelling. Investigations showed the yeast count of Doogh samples more than permitted standard level (Mehraban Sangatash et al., 2011). Other researches also confirmed the presence of mold and yeast contamination in Doogh samples in Zanjan (Mir Alizadeh et al., 2017). A major yeast causative spoilage of yogurt and its products is Kluyveromyces marxianus (Viljoen 2003). One of the non-thermal methods of food processing involves the use of pulsed electric field operations. The use of pulsed electric field causes inactivation of microorganisms without adverse effects especially on flavor and nutritional value (Wang et al., 2018). In this research, the effect of pulsed electric field treatmenton the Kluyveromyces marxianus in Doogh was investigated. Quality of Doogh samples was also determined.

    Material and methods

    The yeast Kluyveromyces marxianus (PTCC 5188) was purchased from Iranian Research Organization for Science and Technology. After activation, cells were incubated in YDP agar at 4°C. For preparation of inoculum, a complete loop of pure yeast colony was transferred to a 250 ml Erlenmeyer flask containing 100 ml of inoculum (5% lactose, 0.3% yeast extract and 0.5% peptone in distilled water) and then placed in a shaker incubator (30°C, 150 rpm, 24 h). Thereafter, yeast cells were isolated by centrifugation at 4500 g for 10 minutes (three times rinsing with deionized water) (Mohammadzadeh et al., 2014). Then, a concentration of 105 cells per ml was prepared (Ebrahimi et al., 2013). Preparation of Doogh samples was done according the following steps. 40% yogurt, 0.7% salt and 59.3% water was mixed (130 rpm). Mixing was continued for 2–3 minutes to prepare a uniform Doogh samples (Foroughinia et al., 2009). In this study, electric field strength (1, 2, 3 and 4 kV / cm) and pulses number (50, 100, 150, 200 and 250) were used. The control sample did not undergo pulsed electric field operation.
     To determine the amount of protein, fat, acidity and dry matter, standard method of Iranian National Standards Organization was used (Iranian Institute of Standardization and Industrial Research; Doogh – Specifications and test method, ISIRI 2453). The pH of the Doogh samples was measured by digital pH meter 744 Metrohm at ambient temperature. Serum separation of Doogh samples were determined according to the following steps. Experimental tubes with specified dimensions (1.4 cm diameter, 16 cm in length) were used to determine the serum separation percentage. These tubes were marked down to a height of 10 cm, this height of 10 cm was considered as100%. The samples were then poured into the tube to the marking line and, after capping, positioned completely vertically and in specific time intervals, the line formed between the two phases was measured, and each milliliter was equal to 1% of the phase separation rate (Foroughi Nia et al., 2009). The flow behavior test was measured at a shear rate range of 11- 321 per second using a Spindle SC4-18 LVDV III Ultra rotary viscometer from Brookfield, USA. Morphological study of yeast cells was performed before and after applying pulsed electric field treatmentusing scanning electron microscope with magnification of 15000-5000.

    Results and discussion

    Doogh had 2.1% protein, 0.98% fat, 6.9% dry matter, acidity=43, pH about 4.2 and apparent viscosity of 10.92 mPa.s.  Evaluation of the yeast population of Kluyveromyces marxianus in different Doogh samples indicates that the yeast population is reduced under conditions of application of pulsed electric field operation. The highest yeast population belonged to the control sample (p <0.05) and application of pulse electric field operation reduced the yeast population and in conditions of pulse electric field operation with electric field strength of 3 kv /cm and pulses number= 200, the log of the yeast population reached about 1.9 ± 0.01. In the conditions of pulsed electric field operation 4 kv / cm and pulses number=250, yeast population continued to decrease, reaching to 1.65 ± 0.01. Statistical analysis showed that there is a significant difference between serum separation of Doogh samples under different conditions of pulse electric field operation including the electric field strength and the number of pulses used (p <0.05). Pulse electric field operation increased percentage of serum separation and control sample had lowest serum separation (52.6%). Depending on the amount of electric field strength and the number of pulses applied, the amount of serum separation in Doogh samples were changed.  In Doogh sample subjected to 1 kv / cm electric field strength and pulses number= 50, serum separation was equal to 53.2 ± 0.5% and in sample subjected to electric field strength= 4 kv / cm and 250 pulses number, the highest serum separation was observed (72±0.8%), and results might be due to the coagulation of proteins during application of pulsed electric field resulting in an increase in serum separation level. Applying pulsed electric field operation did not significantly change the rheological behavior of Doogh samples and it can be concluded that the conditions of pulsed electric field operation studied in this study did not have a significant effect on the intermolecular bonds of the sample proteins. Investigation of the apparent viscosity of Doogh samples under pulsed electric field operation showed that the viscosity values ​​did not change significantly in samples that were exposed to 1 kV/cm and 50 and 100 pulses number, but in other treatments, it caused changes in viscosity compared to the control sample. The highest decrease in viscosity was observed in the treated sample under conditions of 4 kV /cm and 250 pulse number. One of the possible reasons for the decrease in apparent viscosity is that the pulsed electric field results in the coagulation of proteins and the size of distribution of fat globules (Xiang et al., 2011). The results of morphological examination of yeast cells, showed that the pulsed electric field treatmentcaused a change in the morphology of the yeast cell.

    Conclusion

    The results of this study showed that application of non-thermal operation of pulsed electric field reduces the population of Kluyveromyces marxianus, a major causative of swelling of this product. At electric field strength of 4 kv/cm and pulses numbers of 100, 150, 200 and 250, the log of yeast count reaches to the lowest level. Applying pulsed electric field operation caused some changes in the rheological properties of the Doogh and reduced its apparent viscosity compared to the control sample. In addition, the percentage of serum separation, increased as a result of applying this operation.

    Keywords: Doogh, Kluyveromyces marxianus, Pulsed Electric Field treatment
  • E Yousefi, L Nateghi *, N Zand Pages 41-55
    Introduction

    Colors are used to create diversity and enhance the attractiveness of food. Pigment of Echium Amoenum petal in addition to having a natural pigment contain functional compounds such as anthocyanin’s and polyphenols. Research has shown that consuming foods rich in phenolic and anthocyanin compounds increases the body's ability to contract with the disease. Phenolic compounds are one of the most important compounds of fruits, vegetables and juices, and they have an important role in taste properties. It should be noted the phenolic compounds within the fruits, are anthocyanin’s, which play an important role in the color of the fruit. The compounds are soluble in water and are involved in water systems and have very beneficial effects on the health of the body. The use of phenolic compounds, antioxidants and anthocyanin’s in fruits such as pomegranate, strawberry, raspberries, cherries, cranberries, Echium Amoenum petal and etc., prevents the oxidation of LDL in blood (low protein density proteins). The other benefits of these compounds on the body can be cited to reduce cholesterol and anti-diabetic properties, increase prostatic antibodies to help improve heart disease, alzheimer's, breast cancer and intestinal cancer cells. Recently, many restrictions have been expressed by the international organization and research institutes on the use of artificial dye materials. On the other hand, consumers' desire to consume functional products has increased. The purpose of this study was to investigate the physical, chemical characteristics of functional drink based on apple juice and aloe vera containing pigment of Echium Amoenum petal.

    Material and methods

    In the first stage, the pigment of Echium Amoenum petal was extracted. In order to extract pigment from Echium Amoenum petal the maceration and solvent method was used. For this purpose, methanol and water in the ratio of 0.5 to 1.5 were used as the solvent system for extraction. 50 ml of solvent is added to 250 ml of laboratory erlenmeyer flask containing 5 g petals and then erlenmeyer is coated with a strong polyethylene coating to prevent solvent evaporation. The mixture was stored in a German WB22-memmert orbital oscillator at 50 °C for min 5 min until all the pigments are completely extracted. The extract was then separated from the petals by Watman's filter paper No. 1 and condensed by rotary evaporator Buchi water bath B-480 (Germany) at a temperature of 50 °C to Brix 60. The extracted pigments of Echium Amoenum petal were added to two types of beverages aloe vera and apple juice at concentrations of 5 and 10 percentages of volumetric, and the beverages were stored at two temperatures at 4 °C and 25 °C for 15 days. So, eight treatments were designed according to a completely randomized design. The pH test by pH meter, acidity was determined by titration with sodium hydroxide 0.1 N in the presence of phenolphthalein, the content of polyphenol compounds was evaluated using a spectrophotometer apparatus at a wavelength of 725 nm. Total amount of polyphenolic compounds in beverages in terms of gallic acid equivalents was calculated using the equation obtained from the standard curve and the results were expressed in mg gallic acid per milliliter of the extract. Measurement total anthocyanin level by using the differential pH method was measured by a spectrophotometer at 510 to 700 nm. Anthocyanin degradation index by using Spectrophotometer was obtained by dividing the absorption rate at 420 nm to absorbance at 520 nm. The amount of hydroxymethylfurfural contained in beverages was calculated in ppm by high performance liquid chromatography (HPLC). For this purpose, the samples were heated for 20 h. Then 1 ml of each sample was taken and 4 ml of distilled water was added to each of them along with 15% potassium ferrocyanide and 30% acetate. After stirring the samples were placed for 10 min in a 5000 rpm centrifuge and repeated twice. After centrifugation, the floating solution was removed each time, added to each other, and brought to a volume of 10 ml by distilled water. 5 ml of the sample was pour in the separating balloon, and added 5 ml of ethyl ether and mixed well. The bottom solution was discarded and the top solution was kept, and this was repeated. Finally, both solutions were poured together and 5 ml of distilled water was added to the solution. Samples were placed at temperature of 40 °C to remove diethyl ether, then the sample was filtered through 4.5 µm filter paper and injected into the HPLC Infinity 1200, made by Agilent, Germany. The amount of hydroxymethyl furfural in beverages in ppm and was calculated using the equation obtained from the standard curve (National Standard 19709, 2013). For data analysis, Duncan's one-way analysis of variance (ANOVA) was performed using Minitab 16 with 95% confidence.

    Results and discussion

    Based on the results the samples containing aloe vera had lower pH and acidity than apple juice samples. Therefore, after 15 days of storage, the highest pH and the lowest acidity in apple juice containing 10% w/v of pigment were observed at 4 ˚C storage temperature. The amount of anthocyanin’s and polyphenolic compounds increased with increase pigment concentration in samples. The process of reducing these compounds in the beverages stored at 4 ˚C and containing apple juice during 15 days’ storage, was milder. Anthocyanin degradation index and hydroxymethylfurfural amount were lower than samples containing aloe vera juice and increasing the temperature and storage time increased these parameters. In other words, it can be said the effect of the type of drink, storage temperature and extract concentration can have a significant effect on the increase or decrease of all mentioned parameters. Over time, polyphenols content and anthocyanin decrease and over time the pH of the drinks decreased and the acidity increased, also, the amount of hydroxymethylfurfural during the time increased which was a sign of the destruction of sugars over time. In other words, it can be said, the effect the type of drink, storage temperature, and the concentration of the extract has been effective on increasing and decreasing all of the mentioned parameters.

    Conclusion

    The results of this study indicated that the apple juice stored at temperature 4 ˚C and containing 10% w/v pigment of Echium Amoenum petal had the highest amount of polyphenol, anthocyanin and the least anthocyanin degradation, acidity and pH changes, as well as the production of hydroxymethylfurfural over the course of time that it was known as the superior treatment and functional beverage.

    Keywords: Aloe vera juice, Anthocyanin, Apple juice, Echium Amoenum petal, Functional drink
  • H Ghadiri, AM Ziaifar *, M Ghorbani, S Aghazadeh Pages 57-68
    Introduction

    Tomato and tomato based product are widely used as fresh, paste, juice, puree, sauce, etc. Canned tomatoes are an important product worldwide. Peeling is one of the important operations in the tomato industry to ensure good final product quality. In tomato peelings, steam and wet-lye are usually used which is associated with high-energy consumption and environmental degradation, respectively (Wongsa-Ngasri and Sastry 2016b). Thermal treatments are known as the most common method to process the food product. Considering the adverse effect of long thermal process on the chemical and physical aspects of the food, novel heating methods are developed to overcome these limitations. Ohmic heating is a quick thermal method which is known as Joule heating, electrical resistance heating, direct electrical resistance heating, electro-heating and electroconductive heating (Aghajanzadeh and Ziaiifar 2018). In batch ohmic heating system, the food is placed between two electrodes and its temperature increases due to electrical current exposure. In fact, it is used to generate heat uniformly throughout food matrices by controlling the electrical conductivities of food components (Wongsa-Ngasri 2004). Considering the ionic concentration of the food, the increase in the temperature could be rapid resulting in better preservation of the nutritional values and physical aspects of the product. Electroporation is the non-thermal phenomenon which occurs during ohmic heating. This produces the pores with different sizes in the cell walls as a result of alteration in the natural dielectric strength of the cells. In general, ohmic heating has been expanding to other applications to the edge of hybrid technologies such as thawing, blanching, extraction and drying. However, to reach its ultimate benefits for new and higher quality products, further insightful research, on other applications, needed. In this study, ohmic heating system was developed to peel the tomatoes and study the effect of this method on different physicochemical properties of the product.

    Material and methods

    In this study, laboratory scale ohmic peeling system designed and manufactured at Gorgan University of Agricultural Sciences and Natural Resources. The distance between the electrodes (made of stainless steel 314) was 7 cm. In our study, tomatoes ohmically heated in salt solution under various conditions. After initial weighing, the sample placed in salt solution in the ohmic system. Preliminary tests performed to determine the range of operating parameters (salt solution concentration and electric field intensity). The effect of electric field (range from 1500 to 4500 V/m) and concentration of salt solution (range 0.1 to 0.3% w/v) investigated in tomato peeling. After cracking in the tomato skin, the tomato skin easily separated by hand (Wongsa-Ngasri 2004). Hot water peeling at 100° C selected as a control treatment. T-type thermocouple was applied to control the temperature of the cold point of the tomato and the heating medium. The weight loss of the samples was measured considering the difference between the weight of fresh and the peeled tomato vs. the weight of the fresh sample according to Wongsa-Ngasri and Sastry (2016b). Ascorbic acid content of the samples was determined using iodine titration method (Kashyap and Guatam 2012). To study the effect of the peeling methods on the texture, the firmness of tomato was estimated based on the compression percentage as Wongsa-Ngasri and Sastry (2016b) suggested. The optimization of the ohmic peeling was performed using Design Expert software to suggest the best processing condition.

    Results and discussion

    Tomato skin cracking involves thermal, electrical, chemical, biochemical and physical effects. The increase the fruit temperature caused alteration in different physical and chemical properties. During hot water peeling, the process time lasted for 523.33 s. This method brought 16.08% weight loss, 36.08% degradation of the ascorbic acid and 30.86% alteration in the firmness of the sample. The obtained results showed that peeling using the ohmic heating method resulted in faster skin cracking (82s), the less weight loss (10.7%), less ascorbic acid degradation and more stiffness (19.47% compression). The initial temperature of the tomato was 22°C which increased to 40 and 33.22°C after hot water and ohmic heating peeling methods, respectively. It was found that the electric filed intensity and the salt solution concentration had significant effects on the raise in the cold point temperature of tomato. Considering the thermal sensitivity of the ascorbic acid to thermal treatments, it can be mentioned that the ohmic heating peeling was more effective in preserving this vitamin. As, the least vitamin degradation was observed during the tomato processing at 2500 V/m in 0.2% salt solution due to the lower alteration in the sample temperature.
    The change in the weight of the ohmic heated tomato resulted from de-esterification of pectin especially in mesocarp and electroporation effect on the skin destruction. To determine the optimum ohmic peeling conditions was determined based on obtaining the highest level of ascorbic acid content and the least cracking time, weight loss, firmness and alteration in the cold point temperature

    Conclusion

    It could be concluded that the quick rise in the tomato temperature as well as electroporation phenomena enhanced the peeling process in which the product with high nutritional value and quality was produced. In fact, weight loss and compression of the hot water peeled tomato were respectively 6.08% and 11.39% higher than the ohmic heated sample; however, the ohmic peeling brought a higher (4.1%) ascorbic acid content in comparison to the control method. The optimum ohmic peeling condition was processing the tomato in 0.2 W/V salt solution at 2500 V/m. These conditions have shown the potential to be good for processing because they require a reasonably short time. Ohmic heating method can be introduced as an effective method in peeling process of the fruit and vegetable with thin skin such as tomato to produce the high quality product. However, more studied should be performed to investigate other operational parameter affecting the process performance especially using different solution as heating medium and also combining the ohmic heating with other thermal, non-thermal and even chemical peeling methods based on hurdle concept. Besides more physical and chemical properties of the samples could be studied to have a comprehensive view of the effectiveness this novel method.

    Keywords: Ohmic peeling, Optimization, Physical, chemical properties, Tomato
  • M Peyrovani, M Salehifar *, N Karimian Pages 69-86
    Introduction

    Celiac disease is one of the food intolerance disorders in the world. This disease is provoked in genetically susceptible individuals by dietary exposure to wheat gluten and similar proteins in other closely related cereals. The only effective treatment is strict adherence to a 100% gluten free diet for life (Malekzadeh and Shakeri 1386). Patients with Celiac disease should avoid taking gluten-based products (Rampertab and Mullin 2014). Therefore, planning for the production of gluten-free products and their improvement is of particular importance. Lupine or lupines (North America), is a genus of flowering plants in the legume family. Lupine is a leguminous plant that has been studied in this study as a rich source of protein and dietary fiber on the characteristics of gluten-free cake (Kohajdova et al., 2011). The objective of this study was to evaluate the effects of lupine flour (5, 10 and 15%) as a rich source of protein (about 42%) and dietary fiber (about 40%), corn starch (85, 90 and 95%), guar and carrageenan gums (1, 1.5 and 2%) on cake tissue (first and fifteenth days) and organoleptic properties of cake (odour, taste, texture, color and overall acceptance). By adding lupine flour to corn starch and guar and carrageenan gums, gluten-free cake was produced and the optimum formula was obtained with 15% lupine, 85% corn starch, 1% guar gum and 1% carrageenan gum.

    Material and methods

    In this study, the effects of lupine flour, corn starch, guar and carrageenan gums on cake tissue and organoleptic properties were investigated. Lupine flour was purchased from Markal LTD, France. Guar gum from Gum Chemicals LTD, India and carrageenan gum from MSC, Korea. Mono- Diglyceride, gluten-free baking powder, corn starch, oil, salt, sugar and vanilla were prepared by the Nan Sahar group. Cake production was also produced at the Nan Sahar Institute. The cooking temperature was 180°C and the cooking time was 25 minutes. After cooking, they were cooled for 40 minutes at ambient temperature and packed in polyethylene bags.
    In the present study, 20 formulations produced according the mixture design (D- optimal) approach and the effect of Lupine flour (5, 10 and 15%), corn starch (85, 90 and 95%), guar and carrageenan gums (1, 1.5 and 2%), on the viscosity of dough, tissue and sensory evaluation of cake were investigated. Tests were performed in three replications. Analysis of variance (ANOVA) and comparisons of treatments were done using Combined Design, by Design Expert 7.1.5 software.

    Results and discussion

    This research was designed, analyzed and optimized by using the Design-Expert software, Combined D-Optimal Design. ANOVA results showed that fitted models for responses were meaningful (p <0.05). Therefore, the accuracy of the model was confirmed for fitting the information. High content of dietary fiber in lupine flour, by absorbing more water, prevents hardness of the cake tissue and reducing the staling process. Dietary fibre is one of the most important food ingredients used in nutritional and functional foods as it is one of the first ingredients to be associated with the health trend in the 1980s, particularly in bakery and cereal products. Guar and carrageenan gums increase tissue hardness because the gums strengthened the walls of cells forming cavities inside the cake structure. After 15 days, tissue hardness was lower in samples with high lupine. The results of viscosity measurements showed that Lupine flour due to its lack of gluten, reduced viscosity and guar and carrageenan gums, with more water absorption increased viscosity. The results of texture measurement showed that Lupine flour, guar and carrageenan gums reduces the hardness of the tissue. The results of sensory evaluations showed that lupine flour and guar gum improves these properties, but carrageenan gum did not affect the improvement of these. Investigating the effects of Lupine flour on the taste, odour, color, tissue and overall acceptance of gluten-free cakes showed that the increase in Lupine flour had a signtificant effect on them. The protein contained in the lupine flour and glucose in the formulation of gluten-free cake as Millard's precursor compounds, and with the help of the Millard reaction, improves taste and aroma in the gluten-free product. High content of carotenoids in Lupine flour, improved the appearance of the color. Soluble fiber in lupine flour improves the texture and creates a more acceptable tissue for the product. The overall acceptance of samples increased with increasing level of lupine flour.

    Conclusion

    The results of this study showed that the addition of lupine flour to corn starch and guar and carrageenan gums have positive effects on the texture and sensory properties of gluten-free cake. Lupin flour is not only high in dietary fibre but it is also high in protein contents (41–44%) which make it a unique ingredient of high nutritional and commercial value. According to the results, formulation with 15% Lupine flour, 85% corn starch, 1% Guar and 1% carrageenan gums, had a good viscosity, and the tissue was softer and more acceptable and received the highest overall acceptance rating and was selected as the optimal formulation. Lupin flour has shown potential for the manufacture of a range of fibre-enriched products with high consumer acceptability. Consumption of lupin flour-enriched foods has been proven to have many health benefits. Bread prepared by adding lupin flour helped in reducing blood pressure and cardiovascular risk. Addition of lupin fibre to the diet provided favourable changes to some serum lipid measures in men which suggested this novel ingredient may be useful in the dietary reduction of coronary heart disease risk. Breakfasts with lupin flour-enriched bread resulted in significantly higher self-reported satiety and lower energy intake at lunch than normal breakfast. Increasing both protein and fibre intakes, at the expense of refined carbohydrate, may benefit blood pressure. Lupin flour, which is high in both protein and dietary fibre contents, could be an ideal food ingredient that can be used to get the combined effect of protein and fibre in lowering the blood pressure. As compared with other natural protein and dietary fibre sources, lupin flour is lower in
    cost. Therefore, substitution of sweet lupin flour would improve the nutritional value and quality of muffins at economically affordable price.

    Keywords: Celiac, Corn starch, Gluten-free cake, Lupine Flour
  • Kh Arab, M Ghanbarzadeh *, Sh Karimi Pages 87-99
    Introduction

    Over the years, the biological effects ofsynthetic plastics and food packaging waste have raised global concerns about the limitations of their disposal methods. Thus, in the last two decades, there has been a growing interest in the development and growth of biopolymers and technologies that reduce the dependence on fossil fuels. Also, the use of stable bionanocomposite materials has grown significantly (Weber et al., 2002; Sorrentino et al., 2007). CMC is water soluble and has the ability to form flexible and strong films. Carbohydrate films usually have good mechanical properties and good oxygen retention. However, resistance to moisture penetration is weak due to the nature of their hydrophilicity (Rhim et al., 2013). Therefore, in recent years, a lot of research has been done on improving the properties of these films and improving their inhibitory, thermal, physical and mechanical properties. Recently, production of nanocomposites is one of the newest ways to improve the inhibitory, thermal and mechanical properties of food packaging based on biopolymers (Sinha and Bousmina 2005; Rhim 2007; Bordes et al., 2009) On the other hand, another way to improve the inhibitory properties and increase the hydrophobic properties of CMC films is to produce emulsion films and use hydrophobic compounds such as fats in their composition. Fatty acids, such as oleic acid, can potentially improve the moisture retention properties of hydrophilic films. Bioanocomposite refers to a material consisting of two phases, a matrix and a filler, with a filler measuring 1-100 nm. The fillers used include organic compounds (clay particles, cellulose nanoparticles, chitosan and chitin nanoparticles, carbon nanotubes) and inorganic compounds (nanosilver, titanium, dioxide, iron, silica) (De Azerdo et al., 2009). Silver nanoparticles have been used in the production of active packages due to their strong tensile properties on a wide range of microbes, high thermal stability and low volatility (Kumar and Manstedt 2005). According to library studies, the effect of silver nanoparticles on CMC emulsified films has not been investigated. Therefore, the aim of this study was to study the optical properties, water vapor permeability, thermal properties and topographic characteristics of CMC emulsified films.

    Material and method

    To make emulsified films based on carboxymethyl-cellulose-silver nanoparticles, 3 g of CMC powder was dissolved in 180 ml of distilled water and stirred continuously on a magnetic stirrer at 65 ˚C for 45 minutes. After the clear gel was formed, 1 ml of oleic acid (0.3 g / g CMC) and tween 80 (1% by weight of oleic acid) were added to the solution as emulsifiers. Then, in order to homogenize the solution, the Ultra-Turrax T25 homogenizer was used (24000 rpm for 6 min). Different percentages of silver nanoparticles (0.5, 1 and 2 wt % based on CMC) were transferred to 100 ml Erlenmeyer flasks and 20 ml of distilled water was added. In order to better disperse the nanoparticles, they were placed in an ultrasonic bath for 10 minutes.  It was then added to the carboxymethylcellulose-oleic acid solution and stirred for 5 minutes. In the last step, 1.5 ml of glycerol as a plasticizer was slowly added to different parts of the solution and placed on a magnetic stirrer for 20 minutes. Finally, for uniform distribution of the dissolved nanoparticles, it was placed in an ultrasonic bath for 5 minutes. Finally, 50 g of this solution was dried in glass jars at 55 ˚C for 18 hours. Then, the effect of incorporation of the Ag silver nanoparticles on CMC emulsified film optical properties, Water vapor permeability, thermal properties and topographic characteristics were investigated.

    Results and discussion

    The aim of this study was to prepare emulsion films based on CMC and evaluation effect of silver nanoparticles on their physicochemical properties. The amount of WVP decreased significantly with increasing nanoparticle concentration (P <0.05). Silver nanoparticles, by being in the empty spaces of the biopolymer matrix and creating zigzag paths, the path for moving water vapor make hard and long. The rate of transmission in the UV-C (240 nm) range in the CMC film control and samples containing 2% nano silver were 0/01% and percentage of transmission wavelengths in UV-A (nm 360) in CMC film was 78.16%% which by addition of silver nanoparticles, decreased to 11.11%. Also, the rate of inhibition of visible waves (600 nm) by addition of nanoparticles increased. The results of the DSC test showed that Tg by addition of silver nanoparticles decreased from 86/65 ˚C to 83.61˚C, but their thermal resistance increased. According to the X-ray test, the peak intensity of the peaks decreased and their size expanded in 2% concentration. This indicates the uniform distribution of nanoparticles in the biopolymer matrix. Images obtained from AFM show that CMC emulsion films control have a relatively smooth surface. But in nanocomposite films containing 2% silver nanoparticles, surface roughness of the film increased and the uniformity surface their decreased.

    Conclusion

    In this study, emulsion nanocomposite films based on CMC were produced and the effect of silver nanoparticles in different concentrations on its structural properties was studied. The nanoparticles increased film's resistance to WVP, and the film's resistance to UV-VIS waves was improved. The results of XRD showed that the nanoparticles at a concentration of 2% were well distributed in the biopolymer matrix. However, they almost retained their crystalline form. The Tg of the film decreased at concentration of 2% nanoparticles and their surface roughness increased.

    Keywords: Nano silver, Carboxymethyl cellulose film, Emulsified nanocomposite
  • H Aziminezhad, R Esmailzadeh Kenari *, Z Raftani Amiri Pages 101-129
    Introduction

    Excessive oxidative stress can cause multiple chronic diseases such as diabetes, cardiovascular disease, and cancer and aging-related diseases (Kawabata et al 2015). Phytochemicals reduce cardiovascular disease by decreasing the oxidation of LDL, the absorption and synthesis of cholesterol, blood pressure and increasing the blood clotting time. Also, the potential chemical prevention property of these compounds against cancer is caused by their ability to moderate the epigenetic changes of cancer cells (Mahan et al. 2012). Polyphenols have antioxidant activity, plant polyphenols have different functions and can act as a reducing agent, Phenolic acids and their derivatives form a large group of polyphenols that play an important role in the structure of plants, including the cell wall. (Keshavarz et al 2010). The phenolic acids can be classified as either free or bonded phenolic acids (Renger and Steinhart 2000). Free phenolic compounds in the gastrointestinal system can act against the incidence of colon cancer and other chronic diseases, free phenolic acids can be extracted with solvents such as water, methanol, ethanol and acetone. (Min et al 2012). Bonded phenolic acids are compounds that are insoluble, and are bonded to structural components of cellular wall such as cellulose, hemicellulose (for example arabinoxylans), lignin, pectin and structural proteins (Acosta et al 2014). They cannot be extracted by common techniques which lead to less prediction of total phenolic content from the real extent (Ti and al 2014). Hyssop, scientifically known as Hyssopus officinalis, that belongs to the Lamiaceae family (Ghasemi et al 1392). This plant is used as a flavoring and improving organoleptic properties in the food industry and has aromatic compounds that is used in soaps, cosmetics and perfumes. This plant is rich in volatile oils, flavonoids, tannins, marrubiin. This plant has antimicrobial, laxative and antispasmodic properties and has strong antiviral activity against HIV. It is antibacterial, antifungal and has antioxidant properties. Thus, the study aimed at the separation of the free and bonded phenolic factions and the determination of the phenolic content and antioxidant activity of hyssop plant leaf (Hyssopus officinalis) which partly contributes to the better prediction of the phenolic content and antioxidant activity.

    Material and methods

    Extraction of the hyssop plant leaf was carried out by using ultrasound probe under 10 and 20 minutes and the intensity of 60 - 100 W and the use of ethanol: water with ratios (80:20) and (50:50) and separating free phenolic fractions from the extractions using methanol and ultrasound for one hour (adjust the pH in the range of 4.5-5.5 by using 6M HCl), Then centrifuged at 4321 g, for 25 min, the supernatant is free phenolic. And then separating the bonded phenolic factions from residues resulting from the extraction of free phenolic by using caustic soda and ultrasound for two hours (adjust the pH in the range of 4.5-5.5 by using 6M HCl) and then centrifuged at 4321 g for 25 min, the supernatant was used as bonded phenolic extract (Kotásková et al 2016). The antioxidant activity was measured by free radical inhibition tests (DPPH) and the evaluation of colorlessness of beta carotene - linoleic acid, and oxidative stability test (OSI).

    Results and discussion

    The results of this study show that hyssop leaf extract which was extracted by ultrasound probe method contains significant amounts of phenolic and flavonoid compounds and there is a direct relationship between these compounds. Therefore, it can be concluded that hyssop leaf extract has antioxidant activity, and the highest amount of phenolic and flavonoid compounds of the extract, free and bonded phenolic compounds are (20-100-80) respectively. According to the determination of antioxidant activity by DPPH test, the maximum inhibition percentage for the obtained extract from treatment is (20-100-80) and the maximum inhibition amount for free and bonded phenols of the treatment is (20-60-80) and the least IC50 of the obtained extract from the treatment is (20-60-80); and is (20-100-80) for free and bonded phenols and the best treatment of free and bonded fractions was shown by the treatment (20-100-80) in the beta - carotene and OSI tests. Thus, there is a direct relationship between phenolic content, free and bonded phenols in beta - carotene and OSI tests. In DPPH radical inhibition, there was no correlation between phenolic content and antioxidant activity, which could be related to other factors (synergistic or antagonistic effect between active compounds, number and location of hydroxyl groups, presence of impurity in the extract, extraction method, etc.). The results also showed that free phenolic fractions had higher phenolic content and better antioxidant activity than bonded phenols. Free and bonded phenols have benefits for health. The released phenolic compounds in food matrix are used as food preservative. In order to use bonded phenolic compounds in food, pharmaceutical and cosmetic industry, some methods should be designed to release and extract them from the field crops and obtained sediments from extraction, which includes a large part of bonded phenols. Also, separation of free phenols can produce bioactive compounds with high antioxidant properties and can be used more efficiently in food and pharmaceutical industry.

    Conclusion

    Generally, the ratio of solvents, ultrasound intensity and extraction time affect the antioxidant power of hyssop extract. These points indicate the efficiency of ultrasound for recovery of phenolic compounds is mainly due to the cavitation phenomenon. This is due to the emission of ultrasonic waves through a liquid medium which damage the plant wall and improve the solvent penetration and subsequently release the phenolic compounds. In addition, organic solvents are replaced with those which have no toxic effects and consume less energy during the process compared to conventional methods. It also reduces the process time and temperature, which leads it to be useful for extraction of heat - sensitive compounds, such as phenolic compounds. All of these characteristics indicate that ultrasound can be used as a new and alternative process for the use of agricultural and industrial remains and efficient extraction of the phenolic compounds; and it leads to the production of products with high value which have a lot of profit in the industry and finally, it pollutes the environment less than conventional methods.

    Keywords: Ultrasound Probe, Antioxidant Activity, Hyssopus officinalis, Phenolic Compounds, Free Phenolic Compounds, bound Phenolic Compounds
  • Y Pourmohammad, M Gharakhani * Pages 129-141
    Introduction

    Recently, the role and benefits of antioxidants against many human diseases and food spoilage caused by oxidative corruption has attracted a lot of attention. Antioxidants are vital compounds that are widely used as a parameter for food and bioactive drug compounds. Antioxidants are compounds that inactivate oxygen-free radicals in the human Body. Oxygen-free radicals have a strong tendency to combine with vital molecules in the body, including nucleic acids and proteins. Therefor, free radicals, by combining with these molecules, destroy them and thus cause various diseases such as cancers, cardiovascular disease, inflammatory and Weakening of the immune system (Ayub Nejadgan Jahromi and Hasanpour 1397). Pomegranate pulp is a non-edible part and by-product in the juice industry and is a rich source of polyphenol antioxidants and due to its cure and health benefits, it can be used as a nutritious and useful compound (Kazemizadeh and fadaeeie noghani 1393). There are various methods for extracting bioactive compounds. One of the new methods is extraction with subcritical water. Subcritical water is a region of the condensed phase of water, the temperature of which is between 100°C and 374°C, as well as the pressure that the water stays in the liquid state and does not change the phase (Ramos et al 2002). In the present study, two methods for extraction of subcritical water and maceration and also the effects of subcritical water process variables, including temperature and time, on the extraction of antioxidant and polyphenolic compounds of pomegranate pulp extract were investigated.

    Material and methods

    In this project, two methods for extraction including subcritical water and maceration were evaluated to determine the antioxidant capacity and phenolic compounds of pomegranate pulp extract. Extract of subcritical water extraction operation was performed by a subcritical water extraction device in a pilot laboratory. Subcritical water extraction variables were two parameters: temperature (120°C,150°C and 180°C) and time (5, 15 and 25 minutes). Volume of the extracts were 75 ml for each treatment (shaddel et al. 1391). In the method of maceration to prepare the extract, mixture pomegranate pulp powder-water were mixed in a dark environment and ambient temperature for 24 hours using a magnetic stirrer, Then, the mixture was centrifuged to separate the solid phase of extract (Mohamadi et al. 2012). In the extracts, the antioxidant capacity was measured using two

    methods

    the free radical scavenging assay (DPPH) in %RSA (Mohamadi et al. 2012 ) and ferric reducing antioxidant power (FRAP) assay in milligram Fe2+ per gram dry matter (Benzie and Strain 1996), Furthermore, total phenol content by the folin-ciocalteau method in milligram of gallic acid per gram of dry matter (Mohamadi et al. 2012) and flavonoid contents in milligram of quercetin per gram of dry matter (Paul and Bhattacharyya 2015) were evaluated and reported. In this research, statistical analysis was carried out on the effect of temperature and time of extraction by subcritical water on the properties of pomegranate pulp extract from a completely randomized design. (ANOVA) was used to analyze the presence or absence of significant differences between the amounts of different treatments. The results of the analysis of variance method were analyzed at probability level (P<0.01) and averages were compared at probability level (P<0.05). The experiments were carried out in three replications.

    Results and discussion

    The results of the assessment of two methods of maceration and subcritical water showed that the highest extraction was related to the subcritical water method compared to the maceration method. The results of analysis of variance showed that the difference between the values ​​of total phenol, flavonoids, free radical antioxidant and ferric reducing antioxidant for different treatments of pomegranate pulp extract, which was prepared by two methods of subcritical water and maceration, was significant at %1 probability level (P<0.01). The results of the effect of different treatments on the extraction of measured parameters showed that, with increasing temperature and time, the extraction rates of these compounds increased, so that the highest extraction was carried out at treatment at a temperature of 180°C and time of 25 minute. The highest total phenol content was 180°C and time of 25 minute (432.875 mg of gallic acid per gram of dry matter), and the lowest was 120°C and time of 5 minute (205.375 mg / g galic acid per gram of dry matter). In the subcritical water extraction method, with increasing temperature and time in extraction, the amount of flavonoid compounds increased so that the highest amount of flavonoid compounds was related to the treatment of 180°C and time of 25 minute (74.30 mg of quercetin per gram of dry matter) and the lowest amount was related to the treatment of 120°C and time of 5 minute (35.13 mg of quercetin per gram of dry matter). According to the results, the highest amount of antioxidant capacity by DPPH method was related to subcritical water extraction method in 180°C and time of 25 minute (%94.63). According to the results, the highest amount of antioxidant capacity with iron reduction method (FRAP) was related to subcritical water extraction in 180°C and time of 25 minute (1.225 mg of divalent iron per gram of dry matter) and the lowest amount was related to 120°C and time of 5 minute (0.205 mg of divalent iron per gram of dry matter). Increasing the extraction of these compounds by increasing the temperature and pressure in the subcritical water method is described by the fact that water at ordinary temperature and pressure is solvent of polar compounds and non-polar compounds are not soluble in it, But the increase of temperature and pressure reduces the polarity of water and acts as a non-polar solvent, which increases the ability of water to dissolve non-polar compounds. Also, raising the temperature and pressure of water reduces surface tension and viscosity, and thus, during the extraction process, the propagation velocity increases and the mass transfer is facilitated (Brand-Williams et al 1995). In other studies, the results showed that the extracts extracted by subcritical water have significant phenolic and antioxidant compounds than conventional extraction methods and also stated that it was due to increased temperature and pressure during the process, not only the amount of phenolic compounds but also the rate of extraction increased due to increased propagation velocity (Erşan et al 2018; Rangsriwong et al 2009; Mohamadi et al 2012).

    Conclusion

    According to the results, subcritical water extraction can be used as a suitable method for extraction of polyphenolic and antioxidant compounds of pomegranate pulp. Subcritical water is not only an environmentally friendly technology, but also increases the amount of bioactive compounds extracted compared with the maceration method.

    Keywords: Antioxidant, Flavonoid, Phenolic compounds, Pomegranate pulp, Subcritical waterextraction
  • H Dehghani, M Khakbaz Heshmati *, J Dehghannia, H Baghban Pages 143-161
    Introduction

    Potato is a plant of the family (Solanaceae) and due to its vitamins, minerals, energy and high fiber, it is one of the most important agricultural products. Raw potato starch is indigestive, so thermal processing is necessary to increase its digestibility. Due to the increased unwillingness of consumers to use preservatives in food composition, demand for dried potatoes with improved qualitative characteristics has increased. One of the most important operations in food production is drying which reduces the amount of moisture in the food matrix and inhibits microbial and enzymatic activity. So far different methods have been used for drying. One of the most commonly used methods is hot air drying, which has problems and disadvantages, such as high energy consumption and long drying time. Therefore, to reduce the disadvantages of hot air drying, complementary processes such as microwave or infrared drying are used. Microwave drying makes dry products have a good quality in terms of porosity, water reabsorption capacity and shrinkage. Drying with infrared has advantages such as high drying speed, ease of operation, strong sterilization ability and high-quality dried products. Today, combination methods such as Hot air- Microwave and Hot air- Infrared methods are commonly used for drying of food materials. In the Hot air- Microwave method, the volumetric heat generated by the microwave transfers moisture to the surface of the product, and then the moisture is expelled from the surface by the flow of hot air. Also, in the Hot air- Infrared method, when the product is exposed to infrared, this action increases the molecular vibration in the layers of the inner surfaces and leads to an increase in the speed of moisture movement from inside the product to its surface. Finally, water vapor is formed on the surface of the material, which can be easily removed by convection air flow. The use of hybrid methods greatly improves product quality and greatly reduces energy consumption as well as drying time. The purpose of this research was investigation the effect of different drying methods on the quality characteristics of dried potatoes.

    Material and methods

    Potatoes (Variety Agria) were purchased from a local market for this research. The potatoes were cut after washing and peeling in the form of square cubes in the sizes of 1.2×1/2×1/2 cm. Prior to the blanching process, in order to prevent moisture reduction and color change, sliced samples were kept in a lid plate. For the next stage, samples were blanched in a water bath with a temperature control sensor. A 500-ml beaker containing water was placed in the water bath. Once it reached 100 °C, the samples were placed inside the beaker and were blanched for 5 min. Finally, the residual water on the samples was moistened using a tissue and the weight was re-measured. Finally, potato cubes were dried in different methods (Hot air 45 °C with air speed of 1 m/s, Microwave 540 W, Infrared 600 W, Hot air 45 °C- Microwave 540 W, Hot air 45 °C- Infrared 600 W and Hot air 45 °C- Microwave 540 W- Infrared 600 W). Qualitative properties of samples, such as moisture content, effective moisture diffusivity coefficient, water reabsorption, shrinkage, color, and energy consumption were evaluated in this study. In this research, statistical analysis of the experiment data was performed as a factorial design based on a completely randomized design with IBM SPSS Statistics 22 software and the evaluation of the optimum method was done using Design Expert 10 software.

    Results and discussion

    In all methods, moisture ratio constantly reduced. In case of effective moisture diffusivity coefficient, the lowest amount was observed in the hot air method. Since there is a direct correlation between the effective moisture diffusivity coefficient and temperature, and on the other hand, the energy of hot air is lower than irradiation, therefore, effective moisture diffusivity coefficient in this method is lower than other methods. In case of water reabsorption when using microwaves, a significant increase in the rate and amount of this parameter occurs. When hot air, infrared and combinations of these two were used for drying, although rate of shrinkage was low, it was observed that final shrinkage reached the highest value. In these methods, the amount of color change (ΔE) started from zero (control sample) and over time, its amount also increased. The best possible conditions were when the amount of color changes was very low and also the values of (L) and (b) were high and the rate of (a) was low. The smallest amount of color variation was observed in hot air, infrared and hot air-infrared methods. Because in these methods, the process temperature was low compared to the methods used microwave energy, so the intensity of the Millard reaction is also lower, and the color of samples that were dried with these methods, were far better in quality. In terms of energy consumption, the highest amount was related to the methods used hot air. In the methods that used microwave energy for drying, the drying rate and the Effective moisture diffusivity coefficient increased and the process time decreased.When microwave was used for drying, the highest rate of water reabsorption was achieved.The highest amount of shrinkage was observed when the 600 W infrared method was used for drying.

    Conclusion

    In optimum mode, the best conditions were when the amount of shrinkage, color variations, energy consumption and (a) index were low and the rate of water reabsorption, and the indicators (L) and (b) were high. After optimization (based on the optimal qualitative characteristics,) it was determined that the optimum method between different drying methods was the combination of hot air 45 °C-infrared 600 W.

    Keywords: Drying, Hybrid method, Water rehydration, Shrinkage, Energy consumption, Potato
  • B Fathi *, F Ghannadi Asl, K Alirezalou Pages 163-174
    Introduction

    Lycopene, a carotenoid found expressively in red color foods such as tomato and its derivatives, watermelon and papaya, stands out as a powerful bioactive substance due to its antioxidant properties and the great ability to inactivate reactive oxygen species (Pereira et al., 2016). Moreover, clinical evidence supports the action of lycopene in the prevention of various types of cancer (Fu et al., 2014; Van Breemen and Pajkovic 2008). Lycopene as an excellent natural food color has also the advantages. It is stable to heat and an extreme pH value encountered in food processing, has no off-flavors, effective in low concentrations, antioxidant or other claimed health benefits and covers the full range of colors from yellow through orange to deep red. Addition of lycopene as a food color depends on the formulation, method of food preparation, and the manufacturing techniques involved (Kaur et al., 2011). In recent years, consumptions of food products particularly functional dairy products have become more widespread due to its health benefits. The uses of functional dairy products, especially cheese are very important in Iran. Iranian white brined cheese is one of the most common and important sources of calcium in dairy products in a balanced diet and significant source of protein as well as other nutrients. The aim of this study was utilization of lycopene to production of functional white brined cheese with high nutrition and healthy effect and enhancing flavor and color of cheese to increase its acceptability among the consumers.

    Material and methods

    White cheese was made with 3.2% fat and about 8% non-fat solids from cow's milk, pasteurized at 65ºC for 30 minutes and then cooled to 35-38 ºC and rennet was added in the amount of 0.07 g in 5 kg of milk and starter in the amount of 1%w/w (Hansen, Denmark) after dissolving in sterile distilled water was added to the milk and kept at the above temperature for 60 minutes until the curd formed. The formed curd was then cut into small pieces to remove the whey. Moreover, the curd was then pressed to remove more whey, and then different levels of lycopene (200, 400 and 600 ppm) were added to the curd in order to produce the functional cheese and compare it to control cheese. It was kept for one day at 24% brine and then transferred to 8% brine jars and stored during 60 days in order to cheese ripening and to evaluate the effects of adding different levels of lycopene (200, 400 and 600 ppm) on the physico-chemical and sensory properties of white cheese to produce functional cheese compared to control cheese (without lycopene) during 60 days of cheese ripening.

    Results and discussion

    The results of the ANOVA among the treatments indicated that time of cheese ripening affected significantly (P<0.05) pH and reduced in all the samples during storage time. Measurement of proteolysis and lipolysis of cheese samples showed that type of treatment and storage time were significant (P<0.05) on the attributes. By adding lycopene, the proteolysis and lipolysis of the samples increased compared to the control sample, so that the proteolysis and lipolysis (except for cheese with lycopene 600ppm) in all samples increased significantly (P<0.05) during 60 days of cheese ripening. Moreover, measurement of the amount of salt, fat and protein during cheese ripening showed that the effect of treatment and time on the amount of these attributes in cheese samples was not significant (P>0.05).

    Conclusion

    Addition of lycopene in preparation of white brined cheese led to produce a good and acceptable white cheese with high nutritional and healthy food and it’s a good for food consumers because lycopene had red color attractive to consumers beside contains antioxidants and play important roles in health effects. In overall, the results of sensory evaluation (texture, taste and overall acceptability) showed that cheese containing lycopene (400 ppm) had higher score than control cheese and the other cheese samples on 60th day of cheese ripening.

    Keywords: White cheese, Lycopene, physico-chemical, sensory properties
  • H Mousavivand, M Hojati *, H Jooyandeh, H Barzgar, H Zaki Pages 175-188
    Introduction

    Cake is one of the most popular flour products among all age groups especially in children with different types and calories. The high-energy content of various cake is often attributed to the oil, eggs and sugar in their formulation. Sugar is one of the principle ingredients of sponge cake batter that acts as a stabilizer and tenderizer by retarding and restricting the gluten formation and increasing the temperature of egg protein denaturation and starch gelatinization. In addition to making sweets, sugar keeps air bubbles in the texture of the cake and increases the volume of the cake. Despite all the functional benefits of sugar, due to the association with health risks such as high blood pressure, cardiovascular diseases, non-alcoholic fatty liver disease, tooth decay, obesity and diabetes, these days, the demand for low-sugar foods has increased. The replacing sugar with kinds of sweeteners such as natural and artificial ones in cake formulation for reducing amount of sugar is particularly important. Iran is the tenth largest grape producer in the world and grape syrup is one of the grape products with high nutritional and sweetening value that is produced in different regions of Iran. It is an important food product in human nutrition because of the high amounts of monosaccharides and minerals it contains and it is especially an excellent source of iron. The objective of this study was to use the grape syrup powder as a sugar substitute in cup cake.

    Material and methods

    The grape syrup without any added sugar or additives with brix 71 was obtained from Tuyserkan (Hamadan province, Iran) and powdered using a spray dryer and maltodextrin to prevent it from sticking to the machine. Cake flour with 72% extraction rate was purchased from Jonoob Factory (Ahwaz, Khuzestan). In order to make a spongy cake, the grape syrup powder at the five ratios of 0%, 25%, 50%, 75% and 100% were substituted with the sugar in the formulation of cake. The batter of cupcake in this research was prepared using the sugar – dough method. The cake batter was poured into mold and cooked in an oven at 325 °C for 25 minutes. The cakes were exposed to air for 40 minutes to cool. The cakes were then packed in polyethylene bags and stored at ambient temperature and away from direct light. The specific gravity of cake batter was determined by dividing the weight of 240 mL of cake batter by the weight of 240 mL water. Then the physicochemical properties including the moisture content, firmness, volume, porosity, and color and sensory characteristics of the cakes were evaluated weekly during twenty-one days of storage. The moisture content of the samples was evaluated using a hot air oven at 105°C until constant weight. The cake volume was measured using the rapeseed displacement method. A Texture Analyzer was used to calculate the firmness of samples. The porosity of the crumb was investigated by imaging using Image J software. Color determinations of cake crust, including lightness (L), redness (a*), and yellowness (b*) were determined using the digital colorimeter system. A panel of ten trained panelists evaluated the cakes, ages 24–37 years (six females and four male), with sensory evaluation experience in descriptive evaluation of various food products. The sensory features including taste, odor, appearance, texture, and overall acceptability of cakes were performed using a descriptive profile test based on a scale of 1-5; where: 0 = extremely low intensity and 5 = extremely high intensity.

    Results and discussion

    The findings observed that increasing the grape syrup powder ratio caused an increase in specific gravity of the cakes batter, although in each case it was lower than the specific gravity of the control sample. The results showed that replacing sugar with different ratios of grape syrup powder as well as storage time had a significant effect on the characteristics of the cake. The moisture content increased significantly with increasing ratio of grape syrup powder to cake formulation. However, in all treatments, the moisture content of cake samples decreased during storage (p < 0.05). By the time of cake storage up to 21 days, the firmness of all cake samples decreased but the firmness of the cakes made from grape syrup powder was lower than the control sample on all days. On the last day, the samples containing 25% and 50% powder did not differ in firmness but were significantly softer than the control. The volume and porosity of cake samples were affected by sugar substitution with grape syrup powder as it decreased with increasing grape syrup powder ratio but the highest porosity and cake volume were observed in the sample containing 25% powder. By raising the ratio of grape syrup powder to the cake formula, the lightness of the cakes decreased and in other words, the cakes became darker and the redness and yellowness of the cakes increased and decreased, respectively. The sensory evaluation results showed that the samples containing 25% and 100% of the grape syrup powder had the highest and the lowest appearance, respectively. Replacement of sugar with grape syrup powder also improved the cake odor, which was significantly different from the control sample. The control sample and the cake sample containing 25% grape syrup powder had the highest softness and elasticity values. On the other hand, the addition of grape syrup powder produced a better taste than the control sample, with the cake containing 75% of the powder having the highest taste score. The highest and lowest overall acceptability scores were obtained in samples containing 25 and 50% grape syrup powder, respectively. In general, the results of sensory evaluation showed that replacing sugar with ratios of 25 to 50% of grape syrup powder improved some of the sensory properties of the cake.

    Conclusion

    Based on the findings of this study, up to 25% grape syrup powder as a natural sweetener can be replaced with sugar in the cupcake formula.

    Keywords: Cake, Firmness, Organoleptic characteristics, Porosity, Volume