فهرست مطالب

پژوهش های صنایع غذایی - سال سی‌ام شماره 4 (زمستان 1399)
  • سال سی‌ام شماره 4 (زمستان 1399)
  • تاریخ انتشار: 1399/12/17
  • تعداد عناوین: 14
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  • سمیه کلاکی جویباری*، سید هادی رضوی صفحات 1-13

    امروزه به لحاظ صنعتی شدن کشورها، گرایش به مصرف مواد غذایی آماده افزایش یافته است. از جمله این غذاها نودل می باشد. کم تحرکی ومصرف غذاهای آماده در فرآیندهضم وجذب سیستم گوارش تداخل ایجادکند و باعث ایجاد نفخ، یبوست و چاقی شود. از این رو در این تحقیق سعی برآن شده که به نوعی با این مشکلات مقابل کرده ، و بتوان این محصول رابه محصول فراسودمند تبدیل کرده تا علاوه بر کاهش عوارض، سبب افزایش رضایت مندی و سلامت مصرف کننده شود.در این تحقیق از دو ترکیب خمیرترش لاتیکی و سبوس تخمیری گندم به صورت جداگانه و میکس هر دو در تولید نودل استفاده شده است. این پژوهش شامل 9 تیمار و 1 شاهد و3 تکرار بود که آزمون های فیزیکوشیمیایی و میکروبی و ریولوژیکی و ارزیابی حسی بر روی نمونه ها انجام پذیرفت و به منظور مقایسه تیمارها از تجزیه واریانس یک طرفه و به منظور مقایسه میانگین تیمارها از روش چند دامنه ای دانکن استفاده شد. نتایج آزمون ها درقالب فاکتوریل با طرح برپایه کاملا تصادفی در 3 تکرار گزارش شد.

    کلیدواژگان: خمیر سبوس گندم، خمیر ترش لاکتیکی، نودل فراسودمند، طعم و مزه
  • سیده زهرا سیدالنگی*، حبیبه اسکندرلی، زهرا غیاثوند صفحات 15-25
    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 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
  • مریم خاکباز حشمتی*، اکرم پزشکی، ناصر ناصری، مریم جعفرزاده مقدم صفحات 27-38
    استفاده از روغن هسته انگور در رژیم غذایی با توجه به غنی بودن آن از اسیدهای چرب ضروری و ترکیبات آنتی آکسیدانی همچون توکوفرول ها و پلی فنول ها می تواند نقش موثری در سلامتی مصرف کننده داشته باشد. با این حال پایداری اکسیداتیو این روغن نسبتا پایین بوده و مخلوط کردن آن با روغن های پایدارتر از جمله روغن کنجد می تواند روشی مناسب جهت بهبود پایداری اکسیداتیو آن باشد. طی حرارت دهی تغییرات فیزیکی و شیمیایی مختلفی در روغن رخ می دهد که بر کیفیت روغن تاثیر گذار است. در این پژوهش، پایداری حرارتی مخلوط روغن کنجد (75 %) و روغن هسته انگور (25 %) طی 90 دقیقه فرآیند سرخ کردن در دمای C°180 مورد بررسی قرار گرفت. طی فرآیند سرخ کردن، در فواصل زمانی 30 دقیقه شاخص های اصلی کیفی روغن شامل عدد اسیدی، مقدار پراکسید، اندیس پارا آنیسیدین، ترکیبات فنولی و درصد ترکیبات قطبی مورد سنجش قرار گرفتند. نتایج آزمون های اختصاصی روغن های سرخ کردنی نشان داد که با افزایش زمان فرآیند سرخ کردن، میزان عدد اسیدی، اندیس پارا آنیسیدین و درصد ترکیبات قطبی افزایش پیدا کردند ولی مقدار پراکسید تنها تا 60 دقیقه اول فرآیند افزایش یافت و پس از آن کاهش یافت. با افزایش زمان حرارت دهی مقدار ترکیبات فنولی کاهش یافت. مقایسه مقادیر بدست آمده برای فاکتورهای مختلف مخلوط روغن های کنجد و هسته انگور با حدود مجاز استاندارد ملی ایران نشان داد که پارامترهای عدد اسیدی و پرکسید بیش از حدود مجاز استاندارد ملی ایران بود، ولی مقدار ترکیبات قطبی در محدوده مجاز استاندارد ملی ایران قرار داشت. مخلوط روغن های کنجد و هسته انگور برای حرارت دهی طولانی مدت و سرخ کردن مناسب نمی باشد.
    کلیدواژگان: پایداری حرارتی، روغن کنجد، روغن هسته انگور، سرخ کردن، شاخص های کیفی روغن
  • اعظم پولادوند*، بهروز اکبری، مانیا صالحی فر صفحات 39-51
    از آنجایی که در ایران عرقیات گیاهی بعنوان طعم دهنده به دوغ اضافه می شود. تاثیر عرقیات گیاهی بر ویژگی های شیمیایی و میزان اتانول در نوشیدنی دوغ کفیر، مورد ارزیابی قرار گرفت. در این تحقیق 4 نمونه عرقیات طبیعی شامل نعناع، پونه، شوید و بیدمشک بعنوان افزودنیهای طبیعی و سنتی بکار رفت. هر یک از این عرقیات در چهار غلظت 5/0، 2/0، 1/0 و 05/0 درصد (حجمی/حجمی) به نوشیدنی کفیر اضافه شد، سپس این نمونه های طعم دار شده در یک دوره زمانی 21 روزه در دمای 25 درجه سانتی گراد نگهداری گردید و سپس نمونه برداری لازم جهت تعیین میزان درصد اتانول در زمان 7، 10، 14 و 21 روز به روش کروماتوگرافی گازی و انجام آزمایشات شیمیایی انجام شد. در این بررسی مشخص گردید زمان نگهداری و غلظت های عرقیات باعث افزایش معنی دار (05/0 p <) میزان اتانول در نمونه های کفیر شده است و بیشترین میزان اتانول در طی مدت نگهداری به عرق نعناع اختصاص یافت. علیرغم تاثیر معنی دار (05/0 p <) زمان نگهداری و غلظت های عرقیات، میزان اتانول در تمامی نمونه ها در محدوده استاندارد مشاهده شد.
    کلیدواژگان: اتانول، عرقیات گیاهی، کروماتوگرافی گازی، نوشیدنی کفیر
  • منوچهر رشیدی، رضا امیری چایجان*، احمد ارشادی، علی قاسمی صفحات 53-80

    خشک کردن قرص های غذایی یکی از مراحل مهم فرآیند تولید قرص است که در حفظ مواد مغذی آنها نقش بسزایی دارد. در این پژوهش اثر شرایط مختلف خشک کردن مایکروویو- هوای گرم (دمای هوای ورودی، سرعت هوای ورودی و مدت زمان اعمال مایکروویو) بر روی خواص کیفی و شیمیایی قرص فشرده تولید شده از پودر گوجه فرنگی شامل محتوای لیکوپن، غلظت ویتامین ث، محتوای فنل کل، فعالیت آنتی اکسیدانی و شاخص های رنگی ∆L*، ∆a* وb*∆ مورد مطالعه قرار گرفت. برای تجزیه و تحلیل داده ها و بهینهسازی فرآیند از روش سطح پاسخ و طرح مرکب مرکزی استفاده شد. پارامترهای ورودی (مستقل) عبارتند از: دمای هوای ورودی، سرعت هوای ورودی و مدت زمان اعمال مایکروویو و پارامترهای وابسته (خروجی یا پاسخ) عبارتند از: محتوای لیکوپن، غلظت ویتامین ث، محتوای فنل کل ، فعالیت آنتی اکسیدانی و شاخص های رنگی ∆L*، ∆a* وb*∆. برای خشککردن نمونه ها از پنج دمای هوا 40، 50، 60، 70 و C°80، پنج سطح سرعت هوای 5/0، 1، 5/1، 2 و m/s5/2 و پنج سطح مدت زمان اعمال مایکروویو 0، 4، 8، 12 و 16 ثانیه در توان ثابت 90 وات استفاده شد. مقادیر محتوای لیکوپن، غلظت ویتامین ث، محتوای فنل کل، فعالیت آنتی اکسیدانی و شاخص های رنگی ∆L*، ∆a*وb*∆ به ترتیب 5/865 تا mg.100gDM-1 6/2205، 0 تا mgascorbic/gDM88/0، 36/0 تا mg GAE/g DM 9/8، 95/34 تا 02/99 درصد، 89/12 تا 98/18، 35/5 تا 609/14 و 78/6 تا 21/13 بدست آمدند. نقطه بهینه خشک کردن قرص فشرده تولید شده از پودر گوجه فرنگی در دمای هوای C°50، سرعت هوای m/s 07/1 و مدت زمان اعمال مایکروویو 4 ثانیه به دست آمد و مقادیر متغیرهای پاسخ در نقطه بهینه شامل محتوای لیکوپن، غلظت ویتامین ث، محتوای فنل کل، فعالیت آنتی اکسیدانی و شاخص های رنگی ∆L*، ∆a* وb*∆ به ترتیب mg.100gDM-17/434،mgascorbic/gDM66/0،mg GAE/g DM78/7، 11/50 درصد، 76/14، 49/8 و 61/7 بدست آمدند. نتایج نشان داد که خشک کردن تحت دمای پایین تر (C°50) ومدت زمان کم (4 ثانیه) اعمال توان ثابت مایکروویوW) 90) سبب حفظ بیشتر مواد موثره و افزایش شاخص مطلوبیت گردید

    کلیدواژگان: گوجه فرنگی، قرص فشرده، خشک کردن، ویتامین ث، لیکوپن
  • سرور کلانتری، آیناز علیزاده* صفحات 81-93
    زمینه مطالعاتی

    گوشت قرمز به دلیل داشتن پروتئین بالا و کامل از ضروری ترین ترکیبات در رژیم غذایی انسان می باشد. زمینه مطالعاتی: در سال های اخیر مطالعات نشان داده اند که روش های پخت و فرآوری گوشت نه تنها در کیفیت و محتوای ماده چرب بلکه در تشدید شاخص اکسایشی آن موثرند.

    هدف

    در این پژوهش اثر نگهداری در شرایط انجماد بر گوشت ماهیچه در دو تیمار مختلف، ابتدا پخته و سپس منجمد شده (تیمار 1) و منجمد و سپس پخته شده (تیمار 2) مورد مطالعه قرار گرفت.

    روش کار

    ویژگی های فیزیکی شیمیایی نمونه ها در طول 3 دوره زمانی (روز 1، 3 و 5 ماه) مورد بررسی قرار گرفت. نمونه ای نیز بدون تیمار به عنوان نمونه شاهد در نظر گرفته شد. در تمامی ویژگی های فیزیکو شیمیایی و حسی مورد مطالعه (pH، رطوبت، چربی، پروتئین، اندیس پراکسید، تیوباربیتوریک اسید، آهن و رنگ) اثر تیمار بر روی ویژگیهای فوق الذکر در سطح اطمینان 95 درصد معنی دار بودند (05/0>P).

    نتایج

    نتایج حاصل از مقایسه میانگین داده ها نشان داد که در طول مدت نگهداری در هر دو تیمار چربی، pH و آهن به طور معنی داری (05/0>P) کاهش یافته است و میزان پروتئین، پراکسید و تیوباربیتوریک اسید به طور معنی داری (05/0>P) افزایش یافته است. نتیجه این پژوهش نشان داد که تقریبا هر دو نمونه طی 5 ماه به فساد اکسیداتیو می رسند و نگهداری در هر دو تیمار نهایتا تا 3 ماه توصیه می شود.

    نتیجه گیری کلی

    با در نظر گرفتن ویژگی های تغذیه ای که از گوشت انتظار می رود می توان گفت نمونه 1 (گوشت پخته و سپس منجمد شده) به علت حفظ بیشتر آهن و پروتئین و TBA پایین تر که نشان دهنده شدت پایین تر اکسیداسیون است نسبت به تیمار 2 (گوشت منجمد و سپس پخته شده) برتری نسبی دارد و می توان این روش را برای نگهداری گوشت پیشنهاد کرد.

    کلیدواژگان: اثر فرآیند، انجماد، تیمار حرارتی، فیزیکو شیمیایی، گوشت گاو، ویژگی های کیفی
  • سپیده امیرآبادی، جعفر محمدزاده میلانی*، فرشاد صحبت زاده صفحات 95-107
    زمینه مطالعاتی

    فرآیند پلاسما قابلیت اصلاح ساختار صمغ عربی را داشته و درنتیجه باعث تغییر ویژگی های آن می گردد.

    هدف

    بررسی تغییرات ساختاری، ریولوژیکی و فیزیکی صمغ عربی تحت تاثیر تیمار پلاسما بود.

    روش کار

    صمغ عربی به مدت 10 دقیقه تحت تاثیر پلاسما تخلیه سد دی الکتریک هوا قرار گرفت و سپس تغییرات ساختاری، آب دوستی، ریخت شناسی، ریولوژیکی، و رنگ نمونه تیمارشده با صمغ طبیعی (شاهد) مقایسه شد.

    نتایج

    در مقایسه با صمغ عربی طبیعی، تغییراتی در طیف سنجی مادون قرمز نمونه تیمار شده مشاهده گردید که مشهودترین تغییرات مربوط به محدوده عدد موجیcm-1 1200-1750 بود. تیمار پلاسما تاثیری بر ساختار آمورف صمغ عربی نداشت. سطح پودرها پس از تیمار پلاسما ناهموارتر شدند. داده های زاویه تماس آب نشان داد تیمار پلاسما قادر به تبدیل طبیعت فوق آب دوست صمغ عربی به آب گریز است. نتایج آزمون رفتار جریان نشان داد ویسکوزیته ظاهری محلول صمغ طبیعی و تیمار شده با افزایش سرعت برشی کاهش یافت که این نتایج بیانگر رفتار شل شونده با برش نمونه ها بود. مدل پاورلا، با ضریب تبیین بالاتر نسبت به مدل سیسکو، مدل مناسبی برای توصیف رفتار جریان محلول صمغ عربی طبیعی و تیمار شده بود. ویسکوزیته ظاهری محلول صمغ تیمار شده به طور معنی داری (05/0> P) در سرعت برشی ثابت (s-150) در محلول تهیه شده با صمغ تیمار شده بالاتر از صمغ طبیعی بود. تیمار پلاسما باعث تغییر معنی دار رنگ صمغ تیمار شده گردید.

    نتیجه گیری کلی

    درمجموع می توان نتیجه گرفت، تیمار پلاسما فرآیندی کارآمد در اصلاح صمغ عربی با حفظ ساختار اصلی آن می باشد و درنتیجه باعث افزایش آب گریزی و ویسکوزیته صمغ عربی می گردد.

    کلیدواژگان: پلاسما، تخلیه سد دی الکتریک، صمغ عربی، طیف سنجی مادون قرمز، رفتار جریان
  • غلامرضا گوهری*، سیما فریدونی، سیما پناهی راد، نسرین سپهری، محمدرضا دادپور صفحات 109-121

    میوه انگور به علت غنی بودن از ترکیبات پاد اکسیدان و فنلی از ارزش غذایی بالایی برخوردار است. بر همین اساس افزایش غلظت و فعالیت ترکیبات پاد اکسندگی در میوه انگور باعث ارتقای سلامت جامعه و افزایش مقاومت بدن در برابر انواع سرطان ها می شود. لذا به منظور بررسی اثرات محلول پاشی فنیل آلانین بر ویژگی های کیفی حبه های انگور رقم حسینی آزمایش حاضر در یکی از تاکستان های شهرستان مراغه انجام پذیرفت. این آزمایش در قالب طرح کامل تصادفی و با 4 تکرار در چهار سطح تیماری (صفر، 50، 100 و 200 میکرو مولار) اسید آمینه فنیل آلانین انجام گرفت. محلول پاشی در مرحله قبل از رنگ گیری حبه ها در 4 مرحله هر 5 روز یک بار انجام گردید. برای بررسی ویژگی های کیفی و طعم میوه و نیز ظرفیت پاد اکسیدانی حبه های انگور، صفاتی نظیر pH، اسیدیته کل، قند محلول کل، اسید آسکوربیک، محتوای فنل، فلاونویید کل، آنتوسیانین کل ، ظرفیت پاداکسیدان و در نهایت فعالیت آنزیم فنیل آلانین آمینولیاز مورد سنجش قرار گرفتند. نتایج آزمایش نشان داد که کاربرد فنیل آلانین باعث افزایش TSS، pH و اسیدآسکوربیک گردید، ولی این افزایش در غلظت 100میکرومولار بیشتراز سایر تیمارها مشاهده گردید. همچنین با افزایش غلظت فنیل آلانین از صفر به 200 میکرومولار، محتوای اسیدیته کل کاهش پیدا کرد. در عین حال محتوای فنل کل، فلاونویید کل و فعالیت آنزیم فنیل آلانین آمینولیاز افزایش یافت. همچنین بیشترین مقدار ترکیبات پاد اکسیدان کل در غلظت 200 میکرو مولار فنیل آلانین به دست آمد که نسبت به تیمار شاهد 22 درصد افزایش نشان داد. بر اساس نتایج بدست آمده از این پژوهش چنین به نظر می رسد که کاربرد فنیل آلانین با غلظت های بالاتر از 100 میکرومولار باعث افزایش کیفیت و شاخص های تغذیه ای میوه انگور می گردد و این امر می تواند کمک شایانی در افزایش امنیت غذایی جامعه داشته باشد.

    کلیدواژگان: کیفیت میوه، شاخص های تغذیه ای، طعم میوه، انگور
  • محمدیار حسینی*، فریبا لشکری، بابک قنبرزاده صفحات 123-135

    با توجه به افزایش سطح آگاهی مردم در خصوص ارتباط بین مصرف زیاد چربی و بیماری هایی قلبی-عروقی، افزایش فشار خون، چاقی، و سرطان، تقاضا برای تولید فرآورده های لبنی کم چرب از جمله ماست، افزایش چشم گیری داشته است.ولی کاهش چربی، ویژگی های حسی و ریولوژیکی ماست را به گونه ای منفی تحت تاثیر قرار می دهد. از طرف دیگر، فیبرهای پری بیوتیک مانند اینولین و پلی دکستروز، علاوه بر داشتن خواص چربی سانی، دارای منافع تغذیه ای- درمانی بالایی می باشند. .بر این اساس، پژوهش پیش رو با هدف بهبود ویژگی های ریولوژیکی و حسی ماست کم چرب و تولید یک محصول فراسودمند با استفاده از اینولین (صفر، 2 و 3 درصد)، پلی دکستروز (صفر، 2 و 3 درصد) و ژلاتین (صفر و 5/0 درصد) به عنوان جایگزین چربی انجام شد. نتایج آنالیز آماری نشان داد که غلظت های مختلف اینولین و پلی دکستروز اثر معنی داری (05/0p ≤) بر pH و اسیدیته ندارند، اما میزان آب اندازی به صورت معنی داری (05/0p ≤) با افزایش غلظت اینولین و پلی دکستروز کاهش پیدا کرد. در این میان، افزودن غلظت ثابتی از ژلاتین به نمونه های مختلف حاوی اینولین یا پلی دکستروز سبب کاهش بیشتر آب اندازی شد. بررسی ویژگی های ریولوژیکی نشان داد که افزودن اینولین و پلی دکستروز سبب افزایش ویسکوزیته ظاهری، مدول ذخیره و مدول افت ماست کم چرب می شود و افزودن غلظت ثابتی از ژلاتین به نمونه ها سبب بهبود هرچه بیشتر ویژگی-های ریولوژیکی می شود. یافته های آماری ارزیابی حسی ماست کم چرب نشان داد که افزودن اینولین و پلی-دکستروز در کنار غلظت ثابتی از ژلاتین سبب بهبود پذیرش کلی ماست کم چرب می شود. یافته های این پژوهش بیانگر اثر مطلوب اینولین، پلی دکستروز در بهبود ویژگی های مختلف ماست کم چرب می باشد. ه

    کلیدواژگان: اینولین، پلی دکستروز، ژلاتین، ماست کم چرب، رئولوژی
  • محبوبه اکثیری، سید احمد شهیدی، لیلا ناطقی* صفحات 137-149
    زمینه مطالعاتی

    آنتوسیانین ها به طور گسترده به عنوان رنگ های طبیعی در غذاها مورد استفاده قرار میگیرند اما در هنگام ذخیره سازی بسیار مستعد تخریب شیمیایی هستند و این مسئله منجر به از بین رفتن رنگ آنها می شود. یکی از راهکار های موثر در حفظ رنگ و پایداری آنتوسیانینها، کوپیگمنتاسیون است. هدف از این تحقیق: بررسی اثر عصاره های گیاهی طبیعی (چای سبز، رزماری، مریم گلی و گل سرخ) در جلوگیری از تخریب رنگ دانه های آنتوسیانینی موجود در عصاره چای ترش طی دوره نگهداری (7 روز/دمای °C 40 در حضور نور) بود.

    روش کار

    در این مطالعه به عصاره چای ترش با بریکس 12 (به عنوان منبع غنی از آنتوسیانین)، 30 درصد وزنی/وزنی از عصاره های گیاهی (به عنوان کوپیگمنت) برای مهار تخریب آنتوسیانین ها اضافه گردید. به منظور ارزیابی اثر کوپیگمنتاسیون عصاره ها و سرعت بخشیدن به تخریب رنگ دانه های آنتوسیانینی، به نمونه ها میزان 05/0درصد وزنی/وزنی اسید آسکوربیک اضافه شد و سپس تیمار ها در دمای °C40 در مقابل نور به مدت 7 روز نگهداری شدند.

    نتایج

    افزودن عصاره های گیاهی به طور معنی داری (05/0 ≥P) توانست محتوای آنتوسیانینی عصاره چای ترش را حفظ کند. در این میان پلی فنل های موجود در عصاره چای سبز اثر کوپیگمنتاسیون موثرتری را نسبت به سایر عصاره های گیاهی دیگر از خود نشان دادند و شاخص تخریب آنتوسیانین در حضور این ترکیب، در روز 7 نگهداری از 150/3 به 930/1 تقلیل یافت.

    نتیجه گیری کلی

    به طورکلی، این مطالعه استفاده بالقوه از پلی فنل های خاص در تقویت پایداری رنگ دانه های آنتوسیانینی در هنگام استفاده از اسید آسکوربیک را نشان می دهد.

    کلیدواژگان: آنتوسیانین، چای ترش، کوپیگمنتاسیون، اسید آسکوربیک، چای سبز
  • مرجان سقلی، حمید بخش آبادی، راحیل رضایی*، محمود فرمانی صفحات 151-167

    محدودیت اصلی استخراج روغن با پرس میزان بالای روغن باقیمانده در کنجاله است. بنابراین اخیرا تکنیک هایی از قبیل استخراج با فراصوت و ریز موج در این زمینه مورد توجه قرار گرفته است. هدف از این مطالعه بررسی کاربرد پیش تیمار ریزموج-فراصوت در استخراج روغن از دانه های آفتابگردان بود. دانه ها در ابتدا تحت تاثیر پیش تیمار ریزموج با زمان های مختلف فرایند (0 تا 120 ثانیه) و سپس فراصوت با سه سطح زمان مختلف (0 تا 50 دقیقه) مورد تیمار قرار گرفتند. بعد از اعمال این تیمارها، روغن دانه ها با پرس مارپیچی و با سرعت های متفاوت (11 تا 57 دور در دقیقه) استخراج شد و روی این روغن ها آزمایشاتی در قالب طرح باکس بنکن از قبیل میزان راندمان استخراج روغن، ضریب شکست، شاخص رنگ، اسیدیته و ترکیبات فنولی کل صورت گرفت. با افزایش زمان ریزموج و فراصوت راندمان استخراج روغن افزایش یافت هرچند در زمان های بالای فراصوت و یا ریزموج با افزایش این دو پارامتر مقداری راندمان استخراج روغن کاهش یافت ولی با افزایش سرعت دورانی پرس میزان راندمان استخراج کاهش یافت. با افزایش زمان ریزموج و فراصوت و همچنین سرعت دورانی پرس میزان شاخص رنگ و اسیدیته افزایش یافت. تمامی متغیرهای آزمایش بر ضریب شکست روغن ها بی تاثیر بودند و میزان آن برای تمامی نمونه های اندازه گیری شده برابر 0471/1 بود. با افزایش زمان ریزموج و فراصوت فنول کل روغن ها ابتدا افزایش و سپس کاهش یافت. بهینه سازی فرایند نیز نشان داد که اگر زمان ریزموج 71/33 ثانیه، زمان فراصوت 37/28 دقیقه و سرعت دورانی پرس مارپیچی 11 دور در دقیقه باشد منجر به رسیدن به مطلوبیت 851/0 خواهد شد.

    کلیدواژگان: آفتابگردان، پیش تیمار ریزموج- فراصوت، ترکیبات فنولی، ویژگی های
  • فرانک بیگ محمدی*، حمیدرضا ناصری، رضا محمدی، احسان صادقی صفحات 169-179
    زمینه و هدف مطالعاتی

    جایگزینی بیوپلیمر های خوراکی به همراه اسانس های گیاهی به عنوان جایگزین پلیمر های سنتزی، روشی موثر برای نجات محیط زیست، افزایش ایمنی و ماندگاری مواد غذایی در جهان است. گوشت بعنوان مواد غذایی فسادپذیر در بسته بندی های خوراکی فعال حاوی ترکیبات ضدمیکروبی طبیعی می تواند عمر نگهداری و کیفیت بهتری داشته باشد.

    روش کار

    این تحقیق در ادامه و در راستای تکمیل مطالعه قبلی گروه که شامل تولید فیلم ترکیبی کیتوزان ژلاتین حاوی اسانس چویر(Ferulago angulate) و ارزیابی ویژگی های فیزیکی شیمیایی فیلم ها بود، طراحی و انجام شد. فیلم های ترکیبی کیتوزان- ژلاتین حاوی اسانس چویر در سطوح غلظتی 0، 25/.، 5/. درصد (حجمی/ حجمی) با روش کستینگ تولید و ویژگی-های میکروبی، حسی، رنگ و شفافیت فیلم ها جهت نگهداری گوشت بوقلمون در دمای یخچال مورد بررسی قرار گرفت.

    نتایج

    نمونه های بسته بندی شده با فیلم کیتوزان- ژلاتین بدون اسانس در روز دوازدهم نگهداری تقریبا 50 درصد نمرات حسی خود را از دست دادند در حالی که نمونه های بسته بندی شده با فیلم حاوی 5/. درصد اسانس حتی در روز پانزدهم نگهداری دارای نمره قابل قبول بودند و تفاوت معنی داری با سایر نمونه ها داشتند(05/0≥ P). فیلم کیتوزان - ژلاتین در هر سه پارامتر،L* ،a* و b* تحت تاثیر افزودن اسانس قرار گرفت. با افزودن اسانس چویر، شاخص b* و کدورت به مقدار قابل ملاحظه ای افزایش اما شاخص L* کاهش یافت و باعث کاهش شفافیت فیلم و تغییر رنگ به سمت قرمز) (+a و زرد((+b گردید. میانگین شمارش همه اندیس های میکروبی شامل شمارش کلی باکتری ها، شمارش استا فیلوکوکوس اوریوس و شمارش کلی فرم ها در تمام طول دوره اختلاف معنی داری با هم داشتند(05/0≤ p). در روز نهم شمارش کلی در تمام تیمار ها بجز کنترل در محدوده قابل قبول بود.

    نتیجه گیری کلی

    افزودن اسانس چویر در غلظت 5/. درصد فیلم کیتوزان - ژلاتین علاوه بر مهار رشد و تکثیر باکتری ها و افزایش ماندگاری گوشت بوقلمون در یخچال، موجب بهبود ویژگی های حسی فیلم شده که می تواند مزیت و تایید دیگری بر پتانسیل مناسب فیلم کیتوزان - ژلاتین حاوی اسانس چویر برای استفاده به عنوان یک بسته بندی فعال در صنعت گوشت باشد. 

    کلیدواژگان: اسانس چویر(Ferulago angulate)، خواص، فیلم خوراکی، ژلاتین، کیتوزان، گوشت بوقلمون
  • منیره رنجبر*، اکرم آقایی صفحات 181-198
    زمینه مطالعاتی

    یکی از روش های جلوگیری از اکسیداسیون روغنها استفاده از آنتی اکسیدان ها است. استفاده از گیاهان دارویی و ترکیبات موثره آنها به عنوان آنتی اکسیدانهای طبیعی امروزه مورد توجه محققین قرار گرفته است. شاه اسپرغم متعلق به تیرهAsteraseae است. در این مطالعه به جداسازی ترکیبات موجود در اسانس و عصاره های گیاه و تعیین ترکیبات و تاثیر آنها در جلوگیری از اکسیداسیون روغن آفتابگردان پرداخته شده است.

    روش کار

    سرشاخه های گلدار جمع آوری و خشک گردید. اسانس به روش تقطیر با آب استخراج و عصاره هابا روش خیساندن تهیه شد. سنجش میزان فنل، فلاونویید و ترپنویید عصاره ها انجام شد. اجزای اسانس با GC-MS تعیین گردید. اثر عصاره ها در به تاخیر انداختن فساد اکسیداتیو در روغن آفتابگردان تصفیه شده از طریق اندازه گیری عدد پراکسید، عدد باربیتوریک اسید و زمان مقاومت به اکسیداسیون نمونه ها تعیین شد.

    نتایج

    عصاره متانولی از بیشترین میزان فلاونویید و فنل کل عصاره کلروفرمی از بیشترین مقدار ترپنویید برخوردار بود. ترکیبات مهم شناسایی شده در اسانس 1و8-سینول، بتا توجون، سیکلوپنتانول، سیکلوهگزن و بتا بیزابولین بود. در بررسی خاصیت آنتی اکسیدانی عصاره و اسانس شاه اسپرغم در روغن آفتابگردان، با افزایش غلظت اثر آنتی اکسیدانی آنها بیشتر شد. نتایج حاصل از بررسی پایداری اکسایشی روغن حاوی غلظت های مختلف عصاره و اسانس نشان داد که غلظت ppm 1000 عصاره متانولی و اسانس با غلظت 800 ppm نسبت به غلظت های دیگر و نمونه شاهد در پایداری اکسایشی روغن آفتابگردان موثرتر عمل نموده و آنتی اکسیدان سنتزی BHT در غلظت 200 ppm نیز تاثیر بیشتری داشتند.

    نتیجه گیری نهایی

    با مقایسه عصارها می توان نتیجه گرفت که متانول بهترین حلال جهت استخراج فنل و فلاونویید است. از طرفی با توجه به وجود ترکیبات موثر در اسانس این گیاه، می توان از آن بعنوان آنتی اکسیدان استفاده کرد. عصاره متانولی و اسانس با اثر ضد رادیکالی بسیار خوب می توانند جایگزین BHT در روغن آفتابگردان شوند.

    کلیدواژگان: اسانس، شاه اسپرغم، روغن آفتابگردان، فلاونوئید، فنل
  • نفیسه محدثی، هادی کوهساری* صفحات 199-210
    زمینه مطالعاتی: اعضای جنس نعناع از مهمترین گیاهان تولید کننده اسانس می باشند. نعناع آبی با نام علمیMentha aquatica که در مناطق شمال ایران به نام محلی اوجی معروف است از گیاهان ادویه ای رایج محسوب می شود.
    هدف
    این مطالعه با هدف ارزیابی ترکیبات شیمیایی و فعالیت ضد باکتریایی اسانس گیاه اوجی علیه استافیلوکوکوس اوریوس و اشریشیا کلی انجام شد.
    روش کار
    به این منظور اسانس برگ های این گیاه با استفاده از دستگاه تقطیر با آب طرح کلونجر استخراج شد. جهت شناسایی ترکیبات اسانس از کروماتوگرافی گازی-طیف سنجی جرمی (GC-MS) استفاده شد. کمترین غلظت مهارکنندگی(MIC) و کمترین غلظت باکتری کشی(MBC) اسانس مذکور علیه استافیلوکوکوس اوریوس و اشریشیا کلی با روش میکرودایلوشن تعیین شد.
    نتایج
    آنالیز کروماتوگرافی گازی، 27 نوع ترکیب شیمیایی را مشخص کرد که بیش از 98 درصد ترکیبات اسانس را تشکیل دادند. 3- کارن با 24/61 درصد بیشترین ترکیب شناسایی شده در اسانس گیاه اوجی بود. سینیول و لیمونن از دیگر ترکیبات شناخته شده این گیاه بودند که در مقادیر جزیی تر سنجش شدند. نتایج آزمون های ضدباکتریایی حاکی از حساسیت بیشتر استافیلوکوکوس اوریوس نسبت به اشریشیا کلی به اسانس این گیاه بود به طوریکه MIC و MBC این اسانس برای باکتری استافیلوکوکوس اوریوس به ترتیب 56/1 56/1 میلی گرم بر میلی لیتر و علیه اشریشیا کلی 12/3 و 25/6 میلی گرم بر میلی لیتر به دست آمد. نتیجه گیری نهایی: فعالیت ضدباکتریایی اسانس گیاه اوجی (Mentha aquatica) را می توان به وجود مونوترپن های هیدروکربنی مانند 3- کارن در کنار ترکیباتی همچون سینیول، لیمونن، آگاروسپیرول، یوکالیپتول و منتون نسبت داد که پتانسیل استفاده از این اسانس را به عنوان یک نگهدارنده طبیعی در مواد غذایی مطرح می سازد.
    کلیدواژگان: استافیلوکوکوس اورئوس، اشریشیا کلی، ترکیبات شیمیایی، فعالیت ضدباکتریایی، گیاه اوجی
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  • S Kalaki Juybari*, SH Razavi Pages 1-13

    Tendency toward consuming ready-foods has been increased due to industrialization of countries. Noodle is one these foods. Low mobility and consuming ready-foods make interference in digestion system causing bloat, Constipation, and fatness. Therefore, in this study we try to solve this problem and turn this product to a functional product resulting in decreased complications and increased satisfaction and health of consumer.In this study, two mixtures of Lactic sourdough and fermentation wheat bran, both separately and mixed have been used in producing noodle.This includes 9 attendances, 1 witness, and 3 repetitions. Physic-chemical and microbiological and rheological tests and sensual evaluation have been carried out for the samples. One-way ANOVA was used to compare attendances. Multi amplitude test of Duncan was used to compare attendances average. Tests results in the factorial form were reported in 3 repetitions based on completely randomized design. They showed that in lactic sourdough samples in attendance 1 (1%) we have the best texture and appearance.

    Keywords: wheat bran fermentation, lactic sourdough, sensual properties, functional noodle
  • S. Zahra Sayyed-Alangi *, Habibeh Eskandarli, Zahra Ghiasvand Pages 15-25
    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 < /em>≤ 0.05 level.

    Results and discussion

    The findings indicated a significant difference between the treatments (p < /em><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 < /em><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
  • Maryam Khakbaz Heshmati *, Akram Pezeshky, Naser Naseri, Maryam Jafarzadeh Moghaddam Pages 27-38
    Using grape seed oil in the diet due to its richness of essential fatty acids and antioxidant compounds such as tocopherols and polyphenols can play an important role in the health of consumers. However, the oxidative stability of this oil is relatively low and mixing it with more stable oils such as sesame oil can be a good way to improve its oxidative stability. When the oil heated, various physical and chemical changes occur that affects the quality of the oil. In this research, the thermal stability of the mixture of sesame oil (75%) and grape seed oil (25%) was investigated for 90 minutes of frying process at 180°C. During the frying process, at 30 minutes intervals, the main oil qualitative indicators including acid number, peroxide value, p-anisidine value, phenolic compounds, and polar components were measured. The results of specific tests of frying oils showed that, with increasing frying time, the acid number, p-anisidine value, and polar components were increased but peroxide value increased only for the first 60 minutes of the process and then decreased. Comparison of the obtained values for different factors of sesame and grape seed oil with the national Iranian standard limits showed that the parameters of acid number and peroxide value were more than the national standard of Iran, but the content of polar compounds was within the permissible national standard of Iran. Sesame and grape seed oil is not suitable for long term heating and frying. Using grape seed oil in the diet due to its richness of essential fatty acids and antioxidant compounds such as tocopherols and polyphenols can play an important role in the health of consumers. However, the oxidative stability of this oil is relatively low and mixing it with more stable oils such as sesame oil can be a good way to improve its oxidative stability. When the oil heated, various physical and chemical changes occur that affects the quality of the oil. In this research, the thermal stability of the mixture of sesame oil (75% w/w) and grape seed oil (25% w/w) was investigated for 90 minutes of frying process at 180°C. During the frying process, at 30 minutes intervals, the main oil qualitative indicators including acid number, peroxide value, p-anisidine value, phenolic compounds, and polar components were measured. The results of specific tests of frying oils showed that, with increasing frying time, the acid number, p-anisidine value, and polar components were increased but peroxide value increased only for the first 60 minutes of the process and then decreased. Comparison of the obtained values for different factors of sesame and grape seed oil with the national Iranian standard limits showed that the parameters of acid number and peroxide value were more than the national standard of Iran, but the content of polar compounds was within the permissible national standard of Iran. As final result, combination of 75% sesame and 25% grape seed oil is not suitable for long term heating and frying. Using grape seed oil in the diet due to its richness of essential fatty acids and antioxidant compounds such as tocopherols and polyphenols can play an important role in the health of consumers. However, the oxidative stability of this oil is relatively low and mixing it with more stable oils such as sesame oil can be a good way to improve its oxidative stability. When the oil heated, various physical and chemical changes occur that affects the quality of the oil. In this research, the thermal stability of the mixture of sesame oil (75% w/w) and grape seed oil (25% w/w) was investigated for 90 minutes of frying process at 180°C. During the frying process, at 30 minutes intervals, the main oil qualitative indicators including acid number, peroxide value, p-anisidine value, phenolic compounds, and polar components were measured. The results of specific tests of frying oils showed that, with increasing frying time, the acid number, p-anisidine value, and polar components were increased but peroxide value increased only for the first 60 minutes of the process and then decreased. Comparison of the obtained values for different factors of sesame and grape seed oil with the national Iranian standard limits showed that the parameters of acid number and peroxide value were more than the national standard of Iran, but the content of polar compounds was within the permissible national standard of Iran. As final result, combination of 75% sesame and 25% grape seed oil is not suitable for long term heating and frying.
    Keywords: Grape seed oil, Oil quality indicators, Sesame oil, Thermal stability
  • Azam Pouladvand *, B Akbari, M Salehifar Pages 39-51
    Since herbal distillates added to Kefir beverages as flavors in Iran. Then its effects on chemical characteristics and rate of Etanol in the Kefir Beverage were evaluated. In this research, four natural distillates samples like mint, pennyroyal, dill and pussy as natural and traditional additives were used. These were added to kefir beverages at four concentrations % 0.5, 0.2, 0.1 and 0.05 (Volumetric). Then these flavoured samples were kept in a period of 21 days in 25° centigrade temperature. Then we took samples by gas chromatography and chemical experiments to determine the percentage of ethanol during 7, 10, 14 and 21 days. Through this research we found that the storage time and the distillates condensation has caused to significant increase in ethanol level at kefir samples and the most amount of ethanol was dedicated to the distillates of the mint during storage period. In spite of significant effect) p (0.05> of the storage time and the distillates condensation, the rate of ethanol in all samples observed in standard limitation.
    Keywords: Ethanol, Herbal distillates, Gas chromatography, Kefir beverages
  • Manoochehr Rashidi, Ahmad Ershadi, Ali Ghasemi Pages 53-80

    Drying of food tablet is one of the most important peocesses in tablet production that play a vital role in food gradient preservation. In this research, the effect of different conditions of microwave-hot air drying (air temperature, inlet air velocity and microwave exposure time) on the qualitative and chemical properties of the compressed tablet produced from tomato powder containing lycopene content, concentration of vitamin C, total phenol content, antioxidant activity and color indices of ΔL*, Δa* and Δb* were studied. To analyze the data and optimize the process, the response surface method and central composite design were used. Input parameters (independent) were: inlet air temperature, inlet air velocity and microwave exposure time. Dependent parameters (responses) were: lycopene content, concentration of vitamin C, total phenol content, antioxidant activity and color indices of ΔL*, Δa* and Δb*. For drying samples, five levels of air temperatures (40, 50, 60, 70 and 80 °C), air velocity (0.5, 1, 1.5, 2, and 2.5 m/s) and microwave exposure time (0, 4, 8, 12 and 16 seconds) were applied. The amounts of lycopene content, concentration of vitamin C, total phenol content, antioxidant activity, ΔL*, Δa* and Δb* were achievd between 865 to 2205.6 mg.100gDM-1, 0 to 0.88 mgascorbic/gDM, 0.36 to 8.9 mg GAE/g DM, 34.95 to 99.02%, 12.89 to 18.98, 5.35 to 14.609 and 6.78 to 13.21, respectively. The optimum drying point of the at air temperature of 50 °C, air velocity of 1.07 m/s and microwave exposore time of 4 seconds were obtained and the response variable values in the optimal point containing lycopene content, concentration of vitamin C, total phenol content, antioxidant activity and color indices of ΔL*, Δa* and Δb* were obtained 434.7 mg/100gDM,0.66 mgascorbic/gDM, 7.78 mg GAE/g DM, %50.11, 14.76, 8.49 and 7.61, respectively. Results indicated that the drying under lower temperature (50°C) and lower exposore time of microwave radiation (4 seconds) with fixed power (90 W) caused to further ingredient materials preservation and increasing in desirability index. Drying of food tablet is one of the most important peocesses in tablet production that play a vital role in food gradient preservation. In this research, the effect of different conditions of microwave-hot air drying (air temperature, inlet air velocity and microwave exposure time) on the qualitative and chemical properties of the compressed tablet produced from tomato powder containing lycopene content, concentration of vitamin C, total phenol content, antioxidant activity and color indices of ΔL*, Δa* and Δb* were studied. To analyze the data and optimize the process, the response surface method and central composite design were used. Input parameters (independent) were: inlet air temperature, inlet air velocity and microwave exposure time. Dependent parameters (responses) were: lycopene content, concentration of vitamin C, total phenol content, antioxidant activity and color indices of ΔL*, Δa* and Δb*. For drying samples, five levels of air temperatures (40, 50, 60, 70 and 80 °C), air velocity (0.5, 1, 1.5, 2, and 2.5 m/s) and microwave exposure time (0, 4, 8, 12 and 16 seconds) were applied. The amounts of lycopene content, concentration of vitamin C, total phenol content, antioxidant activity, ΔL*, Δa* and Δb* were achievd between 865 to 2205.6 mg.100gDM-1, 0 to 0.88 mgascorbic/gDM, 0.36 to 8.9 mg GAE/g DM, 34.95 to 99.02%, 12.89 to 18.98, 5.35 to 14.609 and 6.78 to 13.21, respectively. The optimum drying point of the at air temperature of 50 °C, air velocity of 1.07 m/s and microwave exposore time of 4 seconds were obtained and the response variable values in the optimal point containing lycopene content, concentration of vitamin C, total phenol content, antioxidant activity and color indices of ΔL*, Δa* and Δb* were obtained 434.7 mg/100gDM,0.66 mgascorbic/gDM, 7.78 mg GAE/g DM, %50.11, 14.76, 8.49 and 7.61, respectively. Results indicated that the drying under lower temperature (50°C) and lower exposore time of microwave radiation (4 seconds) with fixed power (90 W) caused to further ingredient materials preservation and increasing in desirability index. Drying of food tablet is one of the most important peocesses in tablet production that play a vital role in food gradient preservation. In this research, the effect of different conditions of microwave-hot air drying (air temperature, inlet air velocity and microwave exposure time) on the qualitative and chemical properties of the compressed tablet produced from tomato powder containing lycopene content, concentration of vitamin C, total phenol content, antioxidant activity and color indices of ΔL*, Δa* and Δb* were studied. To analyze the data and optimize the process, the response surface method and central composite design were used. Input parameters (independent) were: inlet air temperature, inlet air velocity and microwave exposure time. Dependent parameters (responses) were: lycopene content, concentration of vitamin C, total phenol content, antioxidant activity and color indices of ΔL*, Δa* and Δb*. For drying samples, five levels of air temperatures (40, 50, 60, 70 and 80 °C), air velocity (0.5, 1, 1.5, 2, and 2.5 m/s) and microwave exposure time (0, 4, 8, 12 and 16 seconds) were applied. The amounts of lycopene content, concentration of vitamin C, total phenol content, antioxidant activity, ΔL*, Δa* and Δb* were achievd between 865 to 2205.6 mg.100gDM-1, 0 to 0.88 mgascorbic/gDM, 0.36 to 8.9 mg GAE/g DM, 34.95 to 99.02%, 12.89 to 18.98, 5.35 to 14.609 and 6.78 to 13.21, respectively. The optimum drying point of the at air temperature of 50 °C, air velocity of 1.07 m/s and microwave exposore time of 4 seconds were obtained and the response variable values in the optimal point containing lycopene content, concentration of vitamin C, total phenol content, antioxidant activity and color indices of ΔL*, Δa* and Δb* were obtained 434.7 mg/100gDM,0.66 mgascorbic/gDM, 7.78 mg GAE/g DM, %50.11, 14.76, 8.49 and 7.61, respectively. Results indicated that the drying under lower temperature (50°C) and lower exposore time of microwave radiation (4 seconds) with fixed power (90 W) caused to further ingredient materials preservation and increasing in desirability index.

    Keywords: Tomato, Compressed tablet, Drying, Vitamin C, Lycopene
  • S Kalantari, A Alizadeh* Pages 81-93
    Introduction

    Red meat is one of the most vital ingredients of human diet because of being an important source of protein, Further studies have proven that methods of cooking and processing of meat are effective not only on the fat, but also in increasing its oxidation index, as well. Freezing is a common practice in the meat industry because it preserves meat quality for an extended time and offers several advantages such as insignificant alterations in product dimension, and minimum deteriorations in product color, flavor, and texture. The limit of storage or shelf life of meat has been prevented from being reached by microbiological and physicochemical spoilage under conditions such as refrigeration and freezing. Today, due to the lack of time and employment of women, one of the concerns of home cooking is how to store meat. Usually the meat is kept frozen at home, and whether the meat is cooked in the frozen state or raw is one of the questions facing most women. Therefore, the purpose of this study was to compare the effect of freezing on the quality characteristics of raw and cooked meat to determine the quality characteristics of frozen and then cooked meat. In this research, effects of freezing treatment on beef was investigated in 6 replicates with two different treatments, precooked and then frozen (T1), pre-frozen first and then cooked (T2). The samples physicochemical features have been studied during 5 months of storage. A control sample was prepared without any treatment.

    Material and methods

    pH measurement, moisture content, fat, protein content and peroxide value of meat samples were all analyzed according to national Iranian standards.TBA index was measured according to the method described by AOAC (1990).Iron content was measured with a flame atomic absorption spectrometer according to national Iranian standard. Color measurement as ΔE was analyzed by image processing with Photoshop 8. Texture analyzing test was performed using a texture analyzer (Brookfield LFRA 4500, USA). In this method, the specimen was placed 2 cm in diameter on a porcupine and under a hemisphere. The test was accelerated to 1 mm / s, and the infiltration of the specimen was performed; the infiltration of the specimen and its perforation were reported at high power (Honika, 1997). Analysis of variance (ANOVA) was performed in a completely randomized design using linear plot (G.L.M) with Minitab 16 software. Comparisons of means were performed using Tukey's test at 95% confidence level. Treatments were performed in six replications.

    Results and discussion

    The treatment effect was significant on all the analyzed parameters: pH, moisture, fat, protein, peroxide, TBA and cooking loss (p < 0.05). Results of the mean comparison showed that fat, pH and iron had significantly decreased (p < 0.05), while protein content, peroxide and TBA had remarkably increased (p < 0.05) during storage. The decrease in moisture after slaughter is inevitable due to the decrease in pH (close to the isoelectric pH of proteins), the completion of ATP, and the effects of myofibrillar contractions. These factors all lead to the release of water, which subsequently releases water into the extracellular and sarcoplasmic reticulum of proteins. Water retention was less for frozen samples. Although frozen foods are microbial-resistant, they are subject to chemical changes and their enzymatic activities continue at low intensity. The reason for the decrease in fat was due to the lipid oxidation Fresh meat fat was higher than frozen meat and cooked meat. Certainly, fat removal during baking causes this decrease. Fat content of treatment 2 was higher than treatment 1 and oxidation in treatment 1 was higher. In fact, initial cooking resulted in more fat removal in treatment 1 than in post-freezing cooking (treatment 2), which also differed during the storage period, resulting in lower fat content in the fifth month. Freezing damage the structure of muscle cells by releasing lysosomal and mitochondrial enzymes, iron and other peroxidants, which increase the intensity and speed of protein oxidation. In treatment 1 due to the thermal process initially and inactivation of some enzymes, the proteolysis process is slower. However, in treatment 2, the process of proteolysis has improved. The non-frozen water portion is important in determining oxidation, since some chemical reactions can also occur during freezing storage, primary oxidation during baking, for example, can lead to secondary lipid oxidation during melting (Own & Laurier 1975). As treatment 1 was first cooked and then frozen, oxidation began at the initial heating stage and continued at a lower rate during freezing. For this reason, it had a higher peroxide index than treatment 2 overall. In the overall study, the lowest thiobarbituric acid was in control and the highest in treatment 2 (frozen and cooked) after 5 months of storage. Both treatments (1 and 2) had oxidative corruption within 5 months of storage, although the severity of treatment 2 was higher than that of treatment 1. In fact, the initial curing by enzymatically deactivating was able to reduce the intensity of oxidation during frozen storage. The results of this study showed that the amount of iron decreased significantly over time. Freezing time in particular affects the retention of vitamins and minerals. Iron is in the structure of myoglobin, denaturation leads to increased sensitivity of myoglobin to auto-oxidation and co-oxidizes with iron myoglobin oxidation (Otter et al. 2012). In texture analysis, the results showed the meat become more stiff during storage. The raw state showed more stiffness due to the effect of annealing on protein deterioration. Finally, raw meat (treatment 2) showed higher firmness after 5 months and the nearest firmness to control raw meat. Increased stiffness of meat due to lower moisture content is one of the most common problems that occur due to freezing and storing of frozen fresh meat in the meat texture (Akhtar et al., 2013). Regarding the color, treatment 2 showed less difference with the raw meat which can be concluded that the raw meat in the freezer retains its color better.

    Conclusion

    This research showed that both samples had an oxidative spoilage within 5 months, which offers not to store frozen meat more than 3 months. Considering nutritional features expected from meat, it could be concluded that sample T1 which was the meat that was first cooked and then frozen was preferred to sample T2 because of preserving more iron, protein and having lower TBA index. In sum, cooking meat before freezing is recommended.

    Keywords: Beef, Freezing, heat treatment, physicochemical, process effect, Quality
  • Sepideh Amirabadi, Jafar Mohammadzadeh Milani *, Farshad Sohbatzadeh Pages 95-107
    Introduction

    Gum arabic is a branched polysaccharide and categorized as a protein-arabinogalactan hybrid. The presence of protein part along with the carbohydrate portion has led to its amphiphilic features (Dickinson, 2003). Structurally, it’s a disk structure that includes galactopyranose units in the main and lateral chains. This gum is widely used in the preparation of emulsions, encapsulation of flavors, and the production of hydrogels in the food and non-food industries (cosmetic and pharmaceutical products) (Williams and Phillips 2009). In recent decades, the modification of biopolymers has been one of the interesting topics, on the one hand, to solve their problems and, on the other hand, to develop new products. So far, numerous studies have been done to improve gum arabic properties by various chemical and physical approaches. Among physical methods, cold atmospheric pressure plasma is a new, green, and non-thermal method (De Geyter and Morent 2014). Plasma is defined as an ionized gas consisting of electrons, positive and negative ions, free radicals, excited and non-refractory gases, as well as electromagnetic rays (UV and UV photons( which these particles are constantly interacting with each other( Conrads and Schmidt 2000). One of the applications of cold atmospheric pressure plasma is a modification of biopolymer structures through surface modification. Exposing the surface of biopolymers to bombard electrons, free ions, free radicals, and the emission of electromagnetic radiation causes some chemical and physical reactions on the surface of the material, which also leads to changes in the functional properties of matter. To date, no data have been published on the effect of plasma on gum arabic.

    Material and Methods

    A dielectric barrier discharge apparatus was used for plasma formation and sample treatment. The device consisted of two parallel rectangular aluminum electrodes (17 * 8 cm) with a 28 mm gap between them, and each electrode was covered with a mica sheet as a dielectric barrier. A certain amount of gum arabic powder was placed on the lower plate and treated for 10 minutes. The humidity and ambient temperature were adjusted to 85 and 20 °C, respectively, and were monitored during treatment with a thermo hygrometer. Then flow behavior, FT-IR, XRD, water contact angle, color, and FE-SEM measurements were conducted to evaluate the effect of plasma treatment. The SPSS software using t- student test was applied to evaluate the effect of plasma treatment on gum arabic compared with untreated gum.

    Result and discussion

    The results showed that the oxidation and etching were two effective reactions in plasma treatment of gum arabic. The XRD analysis showed the plasma treatment had no significant effect on the gum arabic amorphous structure, although the increase in the peak of the treated gum compared with control depicted some changes in the structural order of gum arabic happened after plasma treatment. A comparison of the IR spectrum of the treated and control gum confirmed the presence of all informative peaks in relatively similar positions. The most noticeable changes in the IR spectrum of treated gum was recognized between 1750-1200 cm-1. The peak intensity of treated gum increased in band 1722 cm-1 compared with control, which might be due to the formation of carbonyl groups as a result of aldehydes oxidation. Other changes confirmed generation amine groups, carbon-hydrogen bonds, carbon-oxygen bonds as well as destroying some hydroxyl and hydrogen-carbon groups. A comparison of the obtained micrographs revealed that plasma treatment increased the surface roughness of gum arabic powder. Measuring the contact angle of the specimens indicated the ability of the plasma to change the hydrophilic nature of gum arabic to hydrophobic. The main cause of this occurrence was physical and chemical changes due to surface etching and changes in the ratio of hydrophilic and hydrophilic groups. Investigating the variation of viscosity versus shear rate showed that with increasing shear rate, the apparent viscosity of 40% (w/w) of solutions was gradually reduced, indicating that shear-thinning behavior of solutions. The results showed that the application of plasma treatment reinforced the shear-thinning behavior of treated gum arabic solution. The apparent viscosity of the treated gum solution at all applied shear rates was higher than the natural gum solution, which suggesting increasing intermolecular bonding and particle bonding with water as a consequence of plasma treatment. The power-law model properly described the natural and treated gum arabic flow behavior. The color analysis of the samples showed plasma treatment changed the color of gum arabic powder as a consequence of chemical and physical reactions.

    Conclusion

    Gum arabic is mainly used as a stabilizer/emulsifier in the food industry. The present study was performed to evaluate the influence of cold atmospheric pressure-air plasma on physical, rheological, and structural properties of gum arabic. According to the FT-IR and XRD data, plasma treatment did not affect the skeleton and amorphous nature of gum arabic, however, the structure order and some functional groups varied upon plasma treatment. Results of the current paper revealed that air plasma treatment significantly (p < 0.05) increased gum solution viscosity and shear-thinning behavior. The plasma treatment increased the roughness of gum arabic powders as a result of the etching process. The measurement of the contact angle of the specimens indicated the ability of the plasma process to change the hydrophilic nature of gum arabic to hydrophobic. The color of plasma-treated gum changed compare with untreated gum. These results will help researchers to deep insight into the effects of cold atmospheric pressure plasma on composite protein-carbohydrate structures and their new properties and thus finding the new capabilities of this technology as well as modified gum arabic in the food industry.

    Keywords: Dielectric barrier discharge, FT-IR, Flow behavior, plasma
  • Gholamreza Gohari *, Sima Freydoni, Sima Panahirad, Nasrin Sepehri, Mohammad Reza Dadpour Pages 109-121
    Introduction

    Grape berries contain rather high amounts of polyphenolic compounds such as anthocyanins, which contribute significantly to their quality, appearance, and taste. Grape berries produce significant amounts of phenolic compounds. Phenylalanine ammonia-lyase (PAL), is first enzyme in the phenylpropanoid pathway which catalyses the conversion of phenylalanine to flavonoids, phenolics and anthocyanins. Phenylalanine ammonia-lyase (PAL) (EC 4.3.1.24) is an essential enzyme in the phenolic biosynthesis pathway that catalyzes the conversion of L-phenylalanine to trans-cinnamic acid and ammonia. Thus, PAL is the first and decisive step in the phenylpropanoid pathway and is therefore involved in the biosynthesis of phenolic compounds in the plants.The phenylpropanoid pathway involves in the synthesis of secondary compounds such as phenylalanin and phenolics. Considering the positive impacts of phenolic compounds on human health due to their antioxidant properties, their enhancement in fruits and vegetables especially by natural products such as phenylalanin might be considered as promising strategy to fight against cancerous cells and important diseases. Moreover, the increased concentration of phenolics in berries is a critical property benefitting health. In recent years, widespread attention has been focused on the potential beneficial properties on human health of anthocyanins in grapes and their products. Free radical scavenging, antioxidant, antimicrobial, and antiviral activities, nutraceutical and pharmaceutical activities like prevention of cardiovascular disease, protective effects against hepatic damage and disease, anticancer, antitumor, and antimutagenic activities, suppression of inflammatory responses, protection against age-related decline in cognitive behavior, and neuronal dysfunction are some top health beneficial properties of phenolic compounds.

    Material and Methods

    This experiment was conducted in a completely randomized block design using four replications. All reagents and solvents were purchased from Sigma-Aldrich, St. Louis, MO, USA, and used without further purification. Each experimental unit consisted of two plants that each had at least three clusters of approximately the same size, maturity, and development. Vines were sprayed with four concentrations of Phenylalanin (0, 50, 100, and 200 µM) at pre-véraison (in which berries are green and hard) stage. The final volume was reached using distilled water and the pH was set with NaOH (1.0 N) to 7.0. The solutions of Phenylalanin with surfactant TWEEN® 20 were sprayed fifth at 5 days intervals (to ensure that all clusters received sufficient amounts of Phenylalanin solution at pre-véraison stage in case of any rain, deficiency or late development of some berries) on the whole cluster in the early morning. The clusters had little or no evidence of asynchrony and the berries were mostly green and hard. An equal amount of distilled water plus TWEEN® 20 was sprayed to the untreated plants (concentration 0.0 mM). The sprays were carried out with a hand sprayer. At harvest, although not all berries in a cluster were at the same developmental stage, most of the berries should have a particular coloration, softness, and level of development to be harvested.

    Result and Discussion

    The results showed that total phenolics and flavonoids content were significantly enhanced in Phenylalanin -treated (100.0 and 200.0 µM) berries compared to untreated ones. Phenylalanin treatment at all concentrations considerably improved the total antioxidant capacity (DPPH) in the berries and, compared with untreated berries, the activity of phenylalanine amino-lyase enzyme was higher in Phenylalanin -treated fruits. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity of the fruits treated with Phenylalanin were significantly higher than those of the untreated berries. The activity of phenylalanine ammonia-lyase (PAL) in phenylalanin treated fruits significantly increased as compared with the untreated clusters. The remarkable effects of the PAL enzyme in increasing production of phenolic compounds in various plant tissues have been established for a long time, and it seems that the increases in concentrations of phenolic compounds in the present study are significantly related to this enzyme. The PAL enzyme causes the production and accumulation of secondary phenolic metabolites in plant tissues by causing a shift from primary to secondary metabolic pathways, and this accumulation usually increases the nutritional value of plant products. The PAL enzyme causes the production and accumulation of secondary phenolic metabolites in plant tissues by causing a shift from primary to secondary metabolic pathways, and this accumulation usually increases the nutritional value of plant products. Therefore, PAL plays a crucial part in improving the quality of crops by stimulating the production of secondary metabolites. The results of current research indicated that the increased activity of the PAL enzyme was entirely related to concentrations of phenylalanin, and its maximum activity was recorded in the treatment with the highest level (200.0 µM) of the phenyalanin. Moreover, a considerable increase was also observed in the evaluation of the total content of flavonoids, one of the major subgroups of phenolic compounds in plants, in grape berries. At the highest concentration of phenyalanin application, an increase of about 100% was recorded in the production of flavonoids, which can significantly help in the marketability of grape berries in addition to their increased nutritional value.

    Conclusion

    A general evaluation of the results of the present experiment leads us to the conclusion that phenylalanin might be a suitable and recommendable treatment to improve the quality and nutritional value of grape berries. The phenylalanin is an essential amino acid and is safe for human consumption as it is present in almost all plant tissues that have always been consumed by humans without causing any problems. The improvement in the quality of berries, achieved in this research, is partly due to their improved visual quality and partly due to their increased healthful quality, which results from the increase in their antioxidant property and from the accumulation of compounds in them that enjoy high nutritional value. In summary, therefore, it seems that spraying grape berries at pre-véraison can be a suitable and convenient strategy for increasing the quality and nutritional properties of grape berries.

    Keywords: Fruit taste, Grape, Fruit quality, Nutritional properties
  • M Hoseini *, Fariba Lashkari Pages 123-135
    Introduction

    Yogurt is one of the most popular dairy products that is widely consumed around the world, which has received a lot of attention due to its high nutritional value and the presence of beneficial bacteria (Physman et al.  1999). But this dairy product sometimes contains high amounts of fat, which has caused concern among consumers, so the demand of consumers to consume low-fat yogurt has increased. Reduction of fat and consequent reduction of total solids in non-fat and low-fat yogurts, weakens the body and texture of the product and increases hydration, which as a result is not accept by consumers (Aziznia et al 2008). Over the years, low-fat yogurt manufacturers have resorted to using fat substitutes to overcome these problems. The use of fat substitutes reduces the calories in food intake and can improve the physical and organoleptic properties of low-fat products (Gon et al 2005). Hydrocolloids are one of the fat substitutes that have been widely used in recent years. Some of these compounds, in addition to acting as fat substitutes, are known as a prebiotic compound. Prebiotics are indigestible carbohydrate dietary fibers that stimulate the growth and proliferation of bacteria such as Bifidobacterium and Lactobacillus in the large intestine and thus improve host health (Raber Freud2005, Werbeck 2005). These prebiotic carbohydrates include, inulin and polydextrose. Inulin is a polymer of fructose units linked by β (1-2) bonds, usually with a glucose residue at the end of the chain. Inulin is a fermentable dietary fiber and helps improve intestinal function, has a bifidogenic and prebiotic role, increases calcium absorption, reduces triglycerides in people with high fat, and for each gram produces 1.5 kcal of energy (Abbasi and Farzanmehr 2009). This polysaccharide is widely used as a fat substitute and prebiotic compound (Roberfroid 2005). Polydextrose is a low molecular weight polysaccharide (Frank 2002) consisting mainly of 1-6 alpha-linked glucose units, some of which are linked to sorbitol and citric acid (Oliveira and Et al 2009). This material has fibrous and prebiotic properties, sweet taste and does not have any undesirable color in the product, increases the consistency and viscosity without creating turbidity (Codex 1996). This compound is mainly used as a substitute for sugar, starch and fat in food and also has prebiotic properties and beneficial effects on mucous membrane activity (Jay et al 2000). Gelatin is a protein hydrocolloid that has many properties including the ability to bind to water, gel formation, increase viscosity, film formation and emulsifying role. The amphoteric state of gelatin as well as its hydrophobic regions on the peptide chain make it a strong emulsifying and foaming agent (Cheng et al 2008). Various studies have proven the effectiveness of different hydrocolloids on low-fat yogurt. In one study, Gojisberg et al 2009 stated that the addition of inulin significantly improved the textural and sensory properties of low-fat yogurt. In another study, Pimentel et al 2012 reported that the addition of long-chain inulin to milk-produced yogurt produces a tissue similar to whole-milk yogurt, so it can act as a fat substitute. Serisor et al 2013 also reported that the probiotics inulin and polydextrose improve low-fat yogurt tissue and reduce hydration. In another study, Fiszman et al 1999 showed that adding gelatin to yogurt increases the strength of the product up to 9 times and reduces its hydration. The results of most of the mentioned studies show the beneficial effect of these additives in improving the properties of low-fat yogurt and no adverse effect has been observed. However, previous studies have not reported the combined effect of inulin-gelatin and polydextrose-gelatin on the rheological and sensory properties of yogurt.Scientific evidence has demonstrated that consumption of high-fat foods has direct relation with increasing incidences of various diseases such as obesity, diabetes, hardening of the artery walls and blood pressure. Thus, demand for low-fat foods has increasingly been promoted by health-conscious consumers. However, development of low-fat foods is challenging as fat makes a major contribution to sensory attributes of many foods. The objective of this research was therefore to evaluate the effects of inulin (0, 2 and 3 %),  polydextrose (0, 2 and 3 %) and gelatin (0.5%)as fat replacer on the rheological and sensory characteristics of low-fat yogurt.  

    Material and methods

    The materials used in this study included milk (1.5% fat and 9.36% no fat dry matter) from East Azarbaijan Selected Pasteurized Milk Company, Yogurt Starter from Christian Hansen Company of Denmark, Inulin from Sansus Company of the Netherlands, Polydextrose from Denisco Company and Gelatin from Merck Company. In order to produce low-fat yogurt, 500 ml of low-fat milk (1.5% fat) was placed on the steam bath and after reaching 45°C, inulin (2 and 3%), polydextrose (0.5%) and gelatin (0.5%) were added to milk separately. Each treatment was pasteurized at 90°C for 10 minutes and after cooling up to 42°C, commercial starters were added to the sample and then the samples were transferred to incubator 42°C after reaching pH=4.6, the samples were placed in the refrigerator at 5°C until the experiments were performed. 

    Results and discussion

    The results showed that inulin and polydextrose had not significantly (p>0.05) effect on the pH but increasing the inulin and polydextrose caused significant (p≤0.05) decrease in the whey separation. The addition of constant concentration of gelatin to different samples containing inulin or polydextrose, caused to further lowering the whey separation. Regarding the rheological parameters, it was observed that inulin and polydextrose caused a significant (p≤0.05) increase in the storage modulus, loss modulus and viscosity. Addition of constant concentration of gelatin to the samples also improves the rheological properties.Adding different percentages of polydextrose and inulin to low-fat yogurt causes a significant increase (p≤0.05) in color dye compared to the low-fat control yogurt sample, but increases the concentration of inulin and polyene. Dextrose has the opposite effect and reduces the color score, which was statistically significant in relation to samples containing 3% polydextrose and 3% inulin (p≤0.05). Sensory evaluation showed that the overall acceptability of the low-fat yogurt was improved by addition of inulin or polydextrose with constant concentration of gelatin.

    Conclusion

    It was generally concluded that the addition of inulin and polydextrose improve various characteristics of low-fat yogurt. The results suggest that the addition of constant concentration of gelatin to the low-fat yogurt containing inulin or polydextrose had more improving effect on rheological and sensory properties.

    Keywords: : Inulin, Polydextrose, Gelatin, Low-fat yogurt, Rheology
  • Mahbobe Eksiri, Seyed-Ahmad Shahidi, Leila Nateghi * Pages 137-149
    Introduction

    Natural colorants are widely used in food and beverage products due to increasing consumer demand for natural ingredients (Katz & Williams 2011). Anthocyanin is one of the most commonly utilized water-soluble natural colorants and a subclass of flavonoids (Mercadante & Bobbio 2007). They are typically extracted from the red and blue parts of certain plants, including fruits, vegetables, flowers, and leaves. The color stability of anthocyanin is strongly dependent on the pH of the surrounding aqueous phase and they are more stable in acidic rather than in neutral or alkaline solutions. The rate of degradation is affected by many factors including pH, light, temperature, oxygen, enzymes, and ingredient interactions (Malien-Aubert et al. 2001). Besides, anthocyanin also has anti-oxidant and bioactive properties linked to certain health benefits e.g. anti-diabetic, anti-inflammatory, and anti-cancer effects (Tzulker et al. 2007, Olaleye 2007). The stability of anthocyanin color can be enhanced by co-pigmentation phenomenon where the anthocyanin molecule reacts with other natural plant substances through weak interactions forming an enhanced and stabilized color (Gordillo et al. 2012). Co-pigmentation is a solution phenomenon in which pigments and co-pigment molecules form molecular complexes. These cause the pigments to exhibit high color intensity than would be expected from their original. This interaction prevents water attack on the flavylium cation. The most common co-pigments are flavonoids, polyphenolic compounds, alkaloids, amino acids and organic acids (Mazza & Brouillard 1990). Hibiscus sabdariffa is a tropical plant, which belongs to the Malvaceae fam. It is rich in anthocyanins, minerals, pectin. The major reported anthocyanins are delphinidin-3-glucoside, delphinidin-3-sambubioside, and cyanidin-3-sambubioside chiefly responsible for their color and antioxidant properties (Pau-Ling et al. 2002, Jadhav & Bhujbal 2019). Phytochemicals, these natural components, may be able to inhibit the chemical degradation of the anthocyanins and to prolong their color stability. For this reason, many investigations have been carried out to improve the stability of anthocyanins. Therefore, they can be used more widely in food products (Eiro & Heinonen. 2002, Talcott et al. 2003, Clemente & GallI 2011, Jadhav & Bhujbal 2019). The present study is carried out to extract anthocyanins from Hibiscus saddariffa and to improve its stability by copigmentation by four polyphenols (green tea extract, rosemary extract, rose extract, sage extract and in the presence of ascorbic acid). The color stability of anthocyanins is determined by evaluation of the amount anthocyanins, destructive index and total polyphenol during storage at elevated temperature in the presence of light and ascorbic acid in order to accelerate the degradation of anthocyanin pigments.

    Material and methods

    In order to extract Hibiscus saddariffaas, a rich source of anthocyanins, the sepals of this plant were used. First, a weighed amount (6 g) of Hibiscussepal was dissolved in Methanol and water in a ratio of 0.5 to 1.5 as a solvent system. Then, it was kept in an orbital shaker at 40 ℃ for 4 hours to complete anthocyanin pigment extraction. The extract was filtered using whatman No.1 filter paper and concentrated by rotary evaporator at 60℃ to reach 12 brix. In order to prepare other phytochemical extracts (green tea, rosemary, sage and rose), a weighed amount of (260 g) of each phytochemical was dissolved in deionized water and stirred until fully hydrated. Next, 30% w/w of each extract were added to the hibiscus extraction (as a source of anthocyanins) as well as 0.05% w/w ascorbic acid. The pH of the solutions was then adjusted to pH2 using 1 M citric acid. Then, the amount of anthocyanin compounds was determined using pH change method. Besides, destructive index of anthocyanins was evaluated by using absorbance at 420 nm divided by the absorbance at 520 nm. The total amount of polyphenolic compounds of treatments by the folin-ciocalteu reagents was investigated. For this aim, all experiments were analyzed in triplicate in a completely randomized design using the Minitab 16 software using one-way analysis of variance Duncan's test.

    Result and Discussion

    The color stability of anthocyanin in the sample reduced in the presence of ascorbic acid. In the absence of ascorbic acid, the anthocyanin color was stable over seven days. The color fading caused by the presence of ascorbic acid had been proposed to occur through two main mechanisms: (a) a condensation reaction between anthocyanin and ascorbic acid and/or (b) autoxidation of ascorbic acid generating free radicals (e.g., hydrogen peroxide) that cleave the flavylium core of the anthocyanins (Mercadante & Bobbio 2007). In addition, the polyphenols extracts in the presence of ascorbic acid increased the anthocyanin content compared to the control and treatment sample (T2) and also increased the stability of anthocyanin content during storage. Among the co-pigments used (polyphenols extracts), T3 treatment, which contained 30% w/w green tea, had the highest amount of anthocyanin compounds (260/49 mg / l), which could be due to the phenomenon of co-pigmentation. In other words, the higher anthocyanin stability upon green tea addition was due to co-pigmentation, inhibited the ability of water molecules to attack the flavylium ion and caused color loss (Kopjar et al. 2014). According to the obtained results of Degradation index, treatment (T3) with addition of ascorbic acid and green tea extract had the lowest, while the sample (T2) with the addition of ascorbic acid only had the highest degradation index. Those results were in correspondence with the results for anthocyanin content. After preparation, samples with green tea extract addition had the highest anthocyanin content and the lowest degradation index, which means that anthocyanins were more stable. During storage, degradation of anthocyanin occurred and the destructive index increased (Piližota et al. 2012). In terms of total phenolic content, under the defined conditions, T3 treatment containing of green tea extract (30% w/w) had more phenolic compounds than other treatments (5.78 mg/l) and T2 treatment containing ascorbic acid had the lowest polyphenol content (2.85 mg/l). Whereas T3 treatment had more polyphenolic compounds than other samples, anthocyanins and polyphenol structures could be more exposed to each other and more effective co-pigmentation occurred.

    Conclusion

    The results revealed that by using plant extract/polyphenol, solutions could significantly increase the stability of anthocyanins. Among these extracts, green tea extract was the most effective extract in inhibiting the destruction of anthocyanins.

    Keywords: Anthocyanin, Hibiscus saddariffa, Copigmentation, Ascorbic acid, Green tea
  • Marjan Saghali, Hamid Bakhshabadi, Rahil Rezaei *, Mahmood Farmani Pages 151-167
    Introduction

    The sunflower (Helianthus annuusis) an annual verb from Astraceae genus that is grown as a firm bush. One of the oil extraction methods is the mechanical extraction (press) that is usually used in small scales. The main limitation of oil extraction using press is the high amount of residual oil in the meal. Therefore, recently some techniques, such as oil extraction using ultrasound and microwave, are taken into consideration in this case. The ultrasonic waves are some types of mechanical waves that have frequencies are higher than human hearing and microwaves are the non-ionized electromagnetic waves with frequencies range between 300 MH to 300 GH, and are placed between the radio and infrared ray in the electromagnetic spectrum. Regarding the fact that no research is performed in the case of applying the sequential pretreatment of extracting oil from sunflower seeds, for this reason in the current research it was tried to study the utilization of microwave-ultrasound pretreatment in extracting oil from sunflower seeds.

    Materials and methods

    In performing this research the sunflower seeds (contain 38.5 percent oil) was prepared from Agricultural and Natural Resources Research Centre of Golestan Province. Then external materials such as weed seeds, sand and stones were separated by hand and transferred to the Food Industry laboratory of Azad Islamic University of Gonbad-e-Kavoos to perform experiments. At first the seeds were processed by microwave pretreatment with power of 540 watt and different times of process(0 to 120 seconds) and after this they were treated by an ultrasonic bath device with three different time levels(0 to 50 minutes) with stable frequency of 35 KH. After applying these treatments, the oil of seeds were extracted using the screw press with different speeds (11 to 57 rpm) and some experiments such as the efficiency amount of oil extraction, refractive index, color index, acidity and total phenolic compounds were performed on these oils. The response surface methodology, using the Box-Behnken design, was used to evaluate the constant parameters of study in comparison to the variable parameters.

    Results and discussions

    Increase in the microwave and ultrasound time increased the oil extraction efficiency; although in the high ultrasound or microwave times with increase in these two parameters the amount of oil extraction efficiency decreased because of oil outlet ducts destruction. Increase in the oil extraction efficiency with increase in the microwave time can be related to more fracture of oil contained cells or is resulted from decomposition or destruction of protein compounds during treatment with microwave, on the one hand with increase in the ultrasound time some cavitations bubbles are created which have high collapse and explosion power and the force generated from bubbles explosion will lead to an increase in the cell membrane destruction. With increase in the rotational speed of press, the amount of extraction efficiency decreased a little because of reduction in the amount of pressure applied on seeds. The lowest amount of oil acidity that was measured on the basis of Oleic Acid was obtained in the conditions that no pretreatment was used in oil extraction and the rotational speed of screw press was 34 rpm. With increase in the microwave and ultrasound time, the amount of oils color index will increase. Also with increase in the rotational speed of press, the amount of color index increased too. The reason of increase in the amount of color index with increase in the microwave and ultrasound time and also with the rotational speed of press can be attributed to more release of chromogenic compounds in the extracted oil. All of the experiment variables (microwave and ultrasound time and rotational speed of screw press) didn’t have any influence on the refractive index of oils and its amount were equal to 1.0471 for all of the measured and evaluated samples. With increase in the microwave and ultrasound time, the total phenol of oils was increased at first and decreased then. Also optimization of this process indicated that if the microwave time is 33.71 seconds, the ultrasound time is 28.38 minutes and the rotational speed of screw press is 11 rpm, they will lead to obtain the regarded aims. At last it can be said that applying the microwave-ultrasound pretreatment can be propounded as an appropriate pretreatment in the oil extraction industry. With increase in the microwave and ultrasound time, the total phenol of oils was increased at first and decreased then. Also optimization of this process indicated that if the microwave time is 33.71 seconds, the ultrasound time is 28.38 minutes and the rotational speed of screw press is 11 rpm, they will lead to obtain the regarded aims. At last it can be said that applying the microwave-ultrasound pretreatment can be propounded as an appropriate pretreatment in the oil extraction industry. With increase in the microwave and ultrasound time, the total phenol of oils was increased at first and decreased then. Also optimization of this process indicated that if the microwave time is 33.71 seconds, the ultrasound time is 28.38 minutes and the rotational speed of screw press is 11 rpm, they will lead to obtain the regarded aims. At last it can be said that applying the microwave-ultrasound pretreatment can be propounded as an appropriate pretreatment in the oil extraction industry.With increase in the microwave and ultrasound time, the total phenol of oils was increased at first and decreased then. Also optimization of this process indicated that if the microwave time is 33.71 seconds, the ultrasound time is 28.38 minutes and the rotational speed of screw press is 11 rpm, they will lead to obtain the regarded aims. At last it can be said that applying the microwave-ultrasound pretreatment can be propounded as an appropriate pretreatment in the oil extraction industry.

    Keywords: Sunflower, microwave-ultrasound pretreatment, phenol compounds, physicochemical characteristics
  • Faranak Beigmohammadi *, Hamid Reza Naseri, Reza Mohammadi, Ehsan Sadeghi Pages 169-179
    Introduction

    From the mid-twentieth century, petroleum-based polymers including polyethylene and polypropylene have very good stretching properties, high strength, and low weight and plasticity and are widely used in the food packaging. The non-polar and hydrophobic nature of carbon compounds and low surface of these polymers, compared with their high molecular weight, reduce the activity of degrading enzymes and the resistance of synthetic polymers to microorganism attack. As a result, these polymers are not degradable and their aggregation is destructive of the ecosystem of the earth, causing serious environmental problems, which are referred to as white contamination. The use of essential oils (EO) directly in food can cause poisoning, severe aroma, flavor changes, and a change in the appearance of food, while the use of EO in combination with edible films (active packaging), in addition to eliminating that deficiencies, reduce dosage of EO is consumed. Seven species of Ferulago are grown in Iran. Ferulago angulate species has been grown in Kermanshah province and the natural source of mono-terpenes and sis coi-terpenes that have antimicrobial features. Several studies have confirmed the antioxidant and antibacterial effects of Ferulago angulate essential oil (FAEO). However, no valid studies have yet been made about the effects of FAEO in combination with edible films on the physicochemical and thermal properties of the combined gelatin-chitosan film. On the other hand, due to changes in lifestyle, decreased mobility and its problems, including cardiovascular disease, the consumption of white meat, like turkey meat instead of red meat, increased. Turkey meat has been understood and marketed as a healthy substitute to red meat due to its leanness, low cholesterol and desirable fatty acid profile. Turkey breast meat (filet) is believed by consumers worldwide, but is ready to rapid spoilage. Therefore, food industries are seeking technologies to increase its stability. Novel packaging (e.g. active) and processing technologies, in some cases, compounded with “natural” antimicrobials such as EO, have been suggested. So, the combined gelatin-chitosan films contain FAEO produced and its effect on the quality of turkey meat were studied to appointment the suitability of the gelatin-chitosan edible film containing FAEO for keeping and increasing turkey meat shelf life.

    Materials and methods

    The gelatin–chitosan blend edible films were provided according to the casting technique. For interactions of polysaccharides and gelatin, a ratio of 40 to 60 has been reported by the previous works as the optimal ratio for interactions of polysaccharides and gelatin. Therefore, a solution containing 60% gelatin and 40% chitosan (v/v) was prepared to obtain a solution with film forming ability. FAEO was mixed with Tween-80 at 25% (w/w) was added into film forming solution at a concentration of 0, 0.25 and 0.50 % (v/v). The sensory evaluation of the 9-point Hedonic technique was performed (1 was very bad, 9 very good) and 10 panelists were done. The panels were asked to compare the film samples with the control sample in terms of odor, color, and acceptance or overall acceptance. The image processing method was used to examine the color of the films. L*, a* and b* parameters were measured with hunter lab colorimeter and microbial properties assessed as well.

    Results and Discussion

    The chitosan-gelatin films were affected by the addition of essential oil in all three parameters, L*, a* and b*. By adding the essential oil, the b * index and opacity increased significantly but the L * index decreased and reduced the transparency of the film. This phenomenon can be attributed to phenolic compounds in the essential oils, which can absorb light at low wavelengths. The control sample-free coatings due to lipid oxidation and microbial growth have shown signs of corruption as inappropriate for smelling and causing stubbornness. Therefore, they were considered as weak samples and eliminated. For samples that were packaged in the film, they had different sensory scores according to the percentage of EO. Therefore, it can be concluded that using chitosan-gelatin containing FAEO significantly increased the sensory properties of turkey meat (P <0.05). The results of the study indicate that FAEO, improves the sensory properties of turkey meat during the storage period. The initial TVC (log10 CFU/ g) in the control turkey fillet was 3.784 log10 CFU/g, it was 1.897 and 0.401 log10 CFU/g for Staphylococcus aureus and Coliform count respectively. Turkey samples reached or exceeded the value of 7.0 log CFU/g for TVC, which was considered as the upper acceptability limit for poultry fresh meat. The TVC increased slowly during the storage with a long lag phase for packaged samples, while the increase was significantly quick for the control (p < 0.05). The counts of all assessed microbiological indicators were significantly affected (P ≤ 0.05) by the addition of antimicrobials and especially gelatin chitosan edible film containing 0.5 % FAEO. In this study, and of the treatments examined, a film containing 0.5% FAEO was the most effective in inhibiting the growth of TVC, Staphylococcus aureus and Coliform everywhere the storage period. It is well known that, the antimicrobial activity of EO is related to mostly the phenolic ingredients. This result could be attributed to the inhibitory effect of the combined antimicrobials non-polar components such as phenolic di-terpenes (e.g. α-Pinene) are responsible for the antimicrobial properties of FAEO.

    Conclusion

    The use of edible film containing EO is a suitable way to respond to the needs and demands of today's societies to achieve minimal processed foods without using preservatives or chemical additives. In this study, the addition of FAEO to gelatin-chitosan film, in addition to inhibiting the growth and replication of bacteria and increasing the shelf-life of turkey meat in the refrigerator, caused and improved the sensory properties of the samples. In summary, based on the results of this study and according to the previous study, the addition of FAEO oil at a concentration of 0.5%, significantly altered the color and transparency of the films.

    Keywords: Chitosan, Edible Film, Ferulago angulate, Gelatin, Properties, Turkey meat
  • Akram Aghaie Pages 181-198
    Introduction

    There are several methods to prevent oxidation of oils, one of which is the use of antioxidants. Antioxidants are substances that reduce, delay, or stop oxidation reactions. The use of medicinal plants and their active ingredients as natural antioxidants are now considered by researchers. Effective ingredients of plants such as the compounds in the extract and essential oils in the food industry are very important. Tanacetum balsamita is belongs toAsteraseae family. According to numerous applications of this plant in the fields of food and pharmaceutical, In this study, the compounds were isolated in essential oil and of water, methanol, hexane and chloroforms extracts of the plant. The type of existing compounds was identified. Their effect on oxidation of sunflower oil was studied.

    Materials and methods

    The fresh shoots of the plant were collected from west of Isfahan in khordad 1397. Then they were dried in a dark place at room temperature. Essential oil was extracted by water distillation method using Clevenger's apparatus. Water, methanol, hexane and chloroform extracts were prepared by soaking method. The amount of phenol, flavonoids and terpenoid of the extracts were measured by Folin-Sycaltol, aluminum chloride colorimetric and separation in ether methods. The DPPH method was used to evaluate the antioxidant properties of each extract.100 grams of powdered plant in the balloon shed and a ratio of 1 to 5 added water heater was put on. The first 15 minutes of the temperature was set to 150 ° C and then the temperature was adjusted to 50 ° C. It takes 2 hours for the essential oil to form above the sweat. The essential oil was taken twice to obtain the desired amount of essential oil. Essential components were determined by GC-MS.Considering that the antioxidant capacity of the methanolic extract was higher than other extracts and was almost the same as that of the essential oils of the aerial parts.Therefore, they were used as antioxidants to prevent the oxidation of sunflower oil. Methanolic extracts with concentrations of 1000, 500 and 250 ppm were also added with 800 and 600 ppm and BHT antioxidants in two concentrations of 200 and 100 ppm in sunflower oil and 100 grams of refined sunflower oil without addition of extracts or any other combination As an example, the control was considered. The effect of extracts on delaying oxidative degradation in refined sunflower oil was determined by measuring peroxide value, barbituric acid number and oxidation resistance time of samples. The choice of extract used in oil stability was based on the amount of phenolic compounds present. The choice of extract used in oil stability was based on the amount of phenolic compound contents.Result s and

    discussion

    The results showed that methanolic extracts had the highest amount of flavonoid and total phenol (12.98 and 98.38 mg / ml), the chloroform extract had the highest amount of tripnoyid (1320.4 mg / g). Phenol compounds have been extracted with methanol and water solvents better than hexanes and chloroforms. Flavonoids are also extracted by methanol solvent than hexane, chloroform and water. Therefore, flavonoids in this plant are soluble in polar solvents rather than non-polar solvents. The highest percentage of inhibition was associated with methanolic extract with 68.66%. The inhibitory effect of this extract is mostly on non-flavonoids phenolic compounds. The compounds identified in the essential oil were 1, 8 cineole, beta-thujone, cyclopentanol, cyclohexane and the beta bisabolin. Increasing the concentration of extract and essential oil increased the antioxidant effect.During the study period, with increasing concentrations of extract and essential oil, the peroxide value increased.Delay in oxidation and their antioxidant effect.Therefore, the extract used in oil stability was based on the amount of phenolic compounds present.As the concentration of the extract increases, there will be more phenolic compounds. As a result of the increase in the number of hydroxyl groups in the reaction medium, the probability of hydrogen donation to free radicals followed by the inhibitory effect of the extract increases. The results of the study of oil oxidative stability containing different concentrations of extract and essential oil showed that methanolic extract concentration of 1000 ppm and essential oil at 800 ppm concentration compared to other concentrations and control sample was more effective in the oxidative stability of sunflower oil. They had a greater effect Compared to the synthetic antioxidant (BHT) at 200 ppm concentration. The highest oxidation resistance time was observed for samples in which the methanolic extract was used at a concentration of 1000 and an essential oil at a concentration of 800 mg / L. High levels of peroxide value show lower oxidative stability in oil samples. Increasing the concentration of extract and essential oil used to affect the amount of peroxide value, which was decreased by increasing the concentration during the test period. Antioxidants remain active during a certain period of time, and gradually their effect gradually decreases. As a result, increasing the storage time of oil samples under oxidation conditions, the amount of peroxide value increased. All of the antioxidants used in this experiment, had thiobarbituric contents lower than control. 1,8-Cinole and Tujun are more effective in preventing lipid oxidation than other essential oil compounds. Considering that these two substances are the major components of essential oil of the plant, the effect of the essential oil of this plant on the stability of sunflower oil is probably due to the presence of these compounds.Peroxides are the primary product of the oxidation of fats and can be estimated using the peroxide index. High levels of peroxide value show lower oxidative stability in oil samples. In all cases, the peroxide value has increased. The lowest amount was related to oil treatment with 1000 mg / L of methanolic extract, which was statistically different from that of synthetic antioxidant containing 200 mg / L oil and essential oil containing 800 mg / L. With increasing concentrations of extract and essential oil, the oxidation rate has decreased.

    Conclusion

    Therefore, they can be used as a source of natural antioxidants. By comparing the extracts it can be concluded that methanol is the best solvent for the extraction of phenol, flavonoids. On the other hand, the methanolic extract and essential oil of the plant have a high inhibitory effect. Methanol extract and essential oils with Suitable anti-radical effect can be replaced by BHT in sunflower oil.

    Keywords: Essential Oil, flavonoids, Phenol, sunflower oil, Tanacetum balsamita
  • Nafiseh Mohaddesi, Hadi Koohsari * Pages 199-210
    Introduction
    The importance of herbal and spice essential oils is that in addition to creating flavor in foods, their main active ingredient has antimicrobial effects, for this reason, consumers prefer herbal oils to chemicals. The Lamiaceae are a family of flowering plants commonly known as the mint family. Many members of this family are aromatic herbs and are widely used as spices in the food industry. Mentha (also known as mint) is a genus of plants in the family Lamiaceae . The species that makes up the genus Mentha are widely distributed and can be found in many environments. Most grow best in wet environments and moist soils. The genus Mentha consists of over 20-30 species that grow widely throughout the world. Members of this genus are one of the most important plants producing essential oils. There are many varieties of essential oils in different species (Zargari, 1995). Mentha aquatica L. that known in the northern regions of Iran locally called Ojji, is a commonly spice herb has used. This plant grows in aquatic places throughout Iran, especially in northern Iran. One of the main habitats of this plant in Iran is Mazandaran province in northern Iran (Getahun et al., 2008). Food poisoning caused by Escherichia coli and Staphylococcus aureus are known as the most important causes of food poisoning. This study was caried out to evaluate the chemical composition and antibacterial activity of essential oil of Mentha aquatica L. against S. aureus and E. coli
    Material and methods
    Plant of Ojji (Mentha aquatic) was obtained from from local market in Sari township located in Mazandaran Province in northern Iran and was approved by the botany laboratory of Islamic Azad University, Gorgan branch. The essential oil of herb leafs was extracted by hydrodistillation method and Clevenger apparatus. Gas chromatography–mass spectrometry (GC-MS) was used to identify essential oil chemical compounds. The gas chromatograph used was Agilent 6890 with a capillary column of 30 m in length and an internal diameter of 250 μm and a layer thickness of 0.25 μm HP-5MS. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the essential oil of this plant oil were determined using micro-dilution broth method or turbidimetric assay. The Bacterial strains used in this study were two species of Escherichia coli PTCC 1338 and Staphylococcus aureus PTCC 1112. The bacteria were provided in lyophilized form from Biotechnology Institute in Iranian Research Organization for Sciences and Technology, Tehran. Different dilutions of essential oil in Mueller Hinton Broth were exposed with bacterial suspension of 5 ×105CFU/ml of each of the bacteria tested for 24 hours at 37 ° C. After this time the results were recorded as microbial turbidity of visible. The last dilution (lowest concentration) in which microbial turbidity was not observed, as the minimum inhibitory concentration (MIC) was considered. For the determination of MBC, from the tube that contained essential oil concentrations higher than the MIC were cultured onto the Nutrient agar medium. The MBC was defined as the lowest concentration that allowed no visible growth on the agar (Cockerill et al., 2012).
    Results and discussion
    The results of the gas chromatography analysis were determined 27 chemical compounds that formed more than 98% of the essential oil compounds. 3-Carene were the highest concentrations chemical compound of Mentha aquatica essential oil with 61.24%. Cineol, Limonen and Agarospirol were other known compounds of the essential oil of this plant that were measured in quantities of 9.4%, 6.81% and 4.78%, respectively. 3-Carene is a hydrocarbon monoterpene. Therefore, the antibacterial activity of the essential oil of Mentha aquatica can be attributed to the presence of hydrocarbon monoterpens. Identification of the chemical constituents of the essential oil of Mentha aquatica in different parts of the world indicates different reports of the presence of different compounds in this essential oil. Different findings may be due to intrinsic properties of essential oils such as pre-harvest factors such as variety, environmental conditions, ecological factors and differences in extraction methods. Although production of secondary metabolites in plants are made by genetic processes, they are affected by environmental factors. The results of antibacterial tests indicated that S. aureus was more sensitive than E. coli to the essential oil of this plant as MIC and MBC of essential oil of this herb on the S. aureus 1.56 and 1.56 mg/ml and on the E.coli was 3.12 and 6.25 mg/ml respectively. The cause of the lower sensitivity of gram-negative bacteria may be due to the presence of an outer membrane in gram-negative bacteria that restricts the release of hydrophobic components of the essential oil into the lipopolysaccharide layer. One of the important properties of the essential oils is their hydrophobic properties, which distribute them in lipid portions of the cell wall, altering and destroying their structure and increasing their permeability. As a result, much of the ions and other vital contents of the cell leak out, eventually leading to bacterial death. Concerning the antibacterial activity of the essential oils, it has been suggested that phenolic metabolites in plants such as Mentha aquatica are capable of releasing a hydrogen from the hydroxyl group present in their aromatic ring and causing the oxidation of free radicals in lipids and other cellular membrane biomolecules and its destruction and thus produce their antioxidant, antimicrobial and anti-inflammatory properties.
    Conclusion
    The antibacterial activity of essential oil of Mentha aquatica can be attributed to the presence hydrocarbon monoterpene compounds such as 3-Carene along with compounds such as Cineol, Limonen, Agarospirol, Eucalyptol and Menthone that leads the potential for its use as a natural preservative in food.
    Keywords: Mentha aquatica, Chemical composition, Antibacterial activity, Staphylococcus aureus, Escherichia coli