فهرست مطالب

نشریه پژوهش های علوم و صنایع غذایی ایران
سال هجدهم شماره 5 (پیاپی 77، آذر و دی 1401)

  • تاریخ انتشار: 1401/10/20
  • تعداد عناوین: 14
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  • سارا شهریاری، علیرضا صادقی*، مریم ابراهیمی، علیرضا صادقی ماهونک، علی مویدی صفحات 575-588

    ارزیابی خصوصیات ضدمیکروبی و پروبیوتیکی فلورمیکروبی جدا شده از شبه غلات تخمیرشده جهت تامین کشت های میکروبی همراه و آغازگر از اهمیت به سزایی برخوردار است. در این پژوهش، مخمر غالب از خمیرترش باکویت، جداسازی و با استفاده از PCR شناسایی گردید. سپس ویژگی های پروبیوتیکی و همچنین اثر ضدقارچی این جدایه مخمری بر روی Aspergillus niger وAspergillus flavus مورد مطالعه قرارگرفت. توالی یابی محصولات PCR منجر به شناسایی مخمر Pichia kudriavzevii به عنوان جدایه مخمری خمیرترش باکویت شد. نرخ زنده مانی جدایه مذکور پس از تیمار متوالی اسید و صفرا در مقایسه با نمونه شاهد 26/79 درصد بود. همچنین اثر ضدباکتریایی آن در برابر Escherichia coli نسبت به سایر عوامل غذازاد مورد مطالعه به شکل معنی داری (05/0<p) بیشتر بود. با این حال، رشد Listeria monocytogenes در حضور جدایه مخمری 50/19 درصد کاهش یافت اما این جدایه، اثر بازدارنده ای بر Salmonella entrica نداشت. قابلیت های آبگریزی و خوداتصالی جدایه مذکور نیز به ترتیب، 07/64 و 40/67 درصد تعیین گردید. علاوه بر این، جدایه مخمری نسبت به تمامی آنتی بیوتیک های مورد بررسی، مقاومت نشان داد اما در برابر آنتی مایکوتیک های کتوکونازول و فلوکونازول، مقاوم و همچنین نسبت به ایتراکونازول دارای حساسیت نسبی بود. این جدایه مخمری، فاقد فعالیت همولیتیکی بود و اثر ضدقارچی آن در برابر A. niger و A. flavus نیز مورد تایید قرار گرفت. بر این اساس، جدایه P. kudriavzevii از قابلیت مناسبی برای استفاده به عنوان کشت پروبیوتیک و یا محافظت کننده در صنایع تخمیری برخوردار می باشد.

    کلیدواژگان: جدایه مخمری، خمیرترش باکویت، ویژگی های پروبیوتیکی، اثر ضدقارچی
  • کبری تاجیک طوغان، محمدرضا عدالتیان دوم*، سید علی مرتضوی، علی جوادمنش صفحات 589-601

    هدف از انجام این پژوهش، شناسایی گونه های سالمونلا در فرآورده های مرغ با تکیه بر روش Real time PCR است. بدین منظور، تعداد 45 نمونه از فرآورده های ماکیان که شامل سینه، کبد و سنگدان مرغ بودند از نقاط مختلف شهر مشهد و از شرکت های گوناگون خریداری و با رعایت موازین بهداشتی به آزمایشگاه انتقال داده شدند. طبق استانداردهای ایران و بین المللی، در 25 گرم از ماده غذایی، نباید هیچ سالمونلایی وجود داشته باشد. بدین منظور، 25 گرم از هر یک از نمونه ها جدا شده و تحت شرایط استریل به خوبی هموژن شدند و استخراج DNA صورت گرفت. به منظور تایید، DNA استخراج شده توسط الکتروفورز ژل آگارز مورد ارزیابی قرار گرفت. خلوص و کمیت DNA استخراج شده هر یک از نمونه ها توسط طیف سنجی نوری مورد بررسی قرار گرفت. در مرحله بعد به‎منظور شناسایی جنس سالمونلا، نمونه‎ها ‎توسط روشReal time PCR  مورد بررسی قرار گرفتند. نتایج حاصل از Real time PCR نشان داد که از مجموع 45 نمونه، 9 نمونه آلوده به جنس سالمونلا می باشد. سپس این 9 نمونه، از نظر آلودگی به گونه های سالمونلا تیفی موریوم و سالمونلا انتریتیدیس مورد ارزیابی قرار گرفتند که برای این منظور از روش PCR معمولی استفاده شد. نتایج نشان داد از تعداد 9 نمونه که در تست Real time PCR مثبت تشخیص داده شده بود، تعداد 7 نمونه آلوده به سالمونلا تیفی موریوم بوده که از این 7 نمونه، 5 مورد مربوط به سینه مرغ و 2 مورد مربوط به کبد بود و از نظر آلودگی به سالمونلا انتریتیدیس از تعداد 9 نمونه، تنها یک نمونه آلوده بود که مربوط به سینه مرغ می باشد.

    کلیدواژگان: سالمونلا، سالمونلا تیفی موریوم، سالمونلا انتریتیدیس، گوشت مرغ، Real time PCR
  • بهروز علیزاده بهبهانی*، محمد نوشاد، مصطفی رحمتی جنیدآباد صفحات 603-614

    این مطالعه پژوهشی با هدف استخراج عصاره اتانولی برگ زیتون (Olea europaea) و بررسی ویژگی های آنتی اکسیدانی و ضدمیکروبی آن صورت گرفت. عصاره اتانولی برگ زیتون با کمک روش خیساندن تهیه شد و محتوای فنول و فلاونویید کل بر اساس روش های رنگ سنجی معرف فولین- سیوکالتو و کلرید آلومینیوم اندازه گیری گردید. پتانسیل آنتی اکسیدانی عصاره با روش های مهار رادیکال آزاد DPPH و ABTS ارزیابی شد. علاوه بر این، فعالیت ضدمیکروبی عصاره اتانولی برگ زیتون در برابر باکتری های بیماری زا (اشرشیا کلی، انتروباکتر ایروژنز، باسیلوس سریوس و لیستریا اینوکوا) بر پایه روش های دیسک دیفیوژن آگار، چاهک آگار، حداقل غلظت مهارکنندگی و حداقل غلظت کشندگی تعیین گردید. عصاره اتانولی برگ زیتون حاوی mg GAE/g 72/0 ±58/176 فنول کل وmg QE/g 26/0 ±85/69 فلاونویید کل بود. علاوه بر این، عصاره اتانولی برگ زیتون قادر به مهار رادیکال های آزاد DPPH (59/0 ±62/70 درصد) و ABTS (43/0 ±15/76 درصد) بود. نتایج ضدمیکروبی نشان داد اثر ضدمیکروبی عصاره وابسته به غلظت آن و نوع باکتری است و باکتری های باسیلوس سریوس و انتروباکتر ایروژنز به ترتیب حساس ترین و مقاوم ترین سویه های میکروبی در برابر عصاره اتانولی برگ زیتون بودند. به طور کلی، نتایج این مطالعه نشان داد که عصاره اتانولی برگ زیتون را می توان به عنوان ترکیب زیست فعال طبیعی با ویژگی های ضدمیکروبی و آنتی اکسیدانی بالا معرفی نمود.

    کلیدواژگان: برگ زیتون، عصاره اتانولی، ضدمیکروب، آنتی اکسیدان، نگهدارنده طبیعی
  • سعید عزیزخانی، لیلا ناطقی* صفحات 615-630

    امروزه خواص زیست فعال بسیاری از قارچ ها به اثبات رسیده است. یکی از قارچ هایی که به لحاظ دارا بودن خواص درمانی متعدد به عنوان بهترین قارچ دارویی نام گذاری شده است قارچ گانودرما لوسیدوم (Ganoderma leucidum) است. از آنجا که تولید و مصرف مواد غذایی رژیمی و فراسودمند رو به افزایش است و با توجه به وجود ترکیبات فراسودمند موجود در قارچ گانودرما، این قارچ می تواند گزینه ای مناسب جهت تولید محصولات غذایی فراسودمند به حساب آید. لذا هدف از این تحقیق بررسی امکان غنی سازی نان باگت با قارچ گانودرما در سطوح (5/0، 1، 5/1، 2 و 5/2 درصد) به جای آرد و بررسی ویژگی های فیزیکوشیمیایی (درصد خاکستر، رطوبت، فیبر، اسیدیته و pH)، خواص ریولوژیکی (شاخص های مقاومت خمیر، طول کشیده شدن خمیر، کشش پذیری خمیر، ضریب ایندکس، الاستیسیته، زمان پایداری خمیر و انرژی پخت)، بافت سنجی (پیوستگی، فنریت، صمغیت، قابلیت جویدن، چسبندگی و سختی)، ترکیبات فنلی، بیاتی نان، خواص میکروبی (کپک و کلی فرم) و حسی آن بود. بررسی خواص فیزیکوشیمیایی نشان داد با افزایش میزان قارچ گانودرما سطح 5/2 درصد در آرد نان باگت، شاخص های خاکستر، رطوبت، فیبر و اسیدیته افزایش و شاخص pH کاهش یافت. بررسی خواص ریولوژیکی خمیر نشان داد درصدهای مختلف قارچ گانودرما لوسیدوم بر تمامی شاخص های ریولوژیکی خمیر معنی‏دار بود (05/0≥p) و افزودن قارچ باعث کاهش مقادیر شاخص های فوق گردید. نتایج بررسی بافت سنجی نشان داد با افزایش مقدار قارچ گانودرما لوسیدوم تا سطح 5/2 درصد، شاخص پیوستگی، فنریت، صمغیت، قابلیت جویدن و سختی نمونه ها کاهش و شاخص چسبندگی افزایش یافت. مطابق با نتایج افزودن قارچ و افزایش میزان آن تا سطح 5/2 درصد باعث افزایش معنی دار ترکیبات فنلی و فیبر در نمونه های نان گردید (05/0≥p). نتایج ارزیابی میکروبی نشان داد با افزایش قارچ به نان باگت و افزایش میزان آن تعداد کلی فرم ها و کپک در تیمارها به صورت معنی دار کاهش یافت (05/0≥p). بررسی نتایج ارزیابی حسی نشان داد افزایش قارچ تا میزان 5/2 درصد به نمونه‏های نان باگت باعث اندکی کاهش در امتیاز مزه، رنگ، بو و پذیرش کلی در مقایسه با نمونه شاهد گردید. با توجه به نتایج می توان تا 2 درصد به نان باگت قارچ اضافه نمود و از میزان بالاتر فیبر، ترکیبات فنلی، بیاتی و بار میکروبی کمتر آن در نان باگت بهره جست بدون اینکه اثر نامطلوب روی خواص حسی آن داشته باشد.

    کلیدواژگان: غنی سازی، نان باگت، قارچ گانودرما لوسیدوم، Ganoderma leucidum
  • علیرضا عباسی، آرش کوچکی، الناز میلانی*، محبت محبی صفحات 631-647

    در راستای تغییر عادت های غذایی مصرف فراورده‏های غله صبحانه به علت قابلیت مصرف راحت، مقرون به صرفه بودن و ارزش تغذیه‏ای بالا، دو چندان شده است. این فراورده‏ها لزوما باید ساختاری فشرده و متراکم با تخلخل کم داشته باشند تا در هنگام غوطه وری در شیر به واسطه سرعت جذب آب آهسته فراورده سبب حفظ بافت و تردی آن گردد. ضروری است جهت دستیابی به بافت مطلوب و تعدیل تجزیه نشاسته از دانه های با فیبر رژیمی بالا و فرایند اکستروژن استفاده گردد. اگرچه ادغام فیبر در فراورده ها، چالش های تکنولوژیکی به همراه دارد اما با استفاده از دانه برنج به عنوان منبع مهم نشاسته و مالتودکسترین می توان به ویژگی های مورد نظر رسید. در این پژوهش با هدف دستیابی به فراورده غله صبحانه با خصوصیات فیزیکوشیمیایی، عملکردی و حسی مطلوب، ارزیابی اثر متغیرهای فرایند اکستروژن شامل رطوبت (12، 15 و 18 درصد)، سرعت مارپیچ (140، 170 و 200 دور بر دقیقه) و میزان کنجاله کتان (10، 20 و 30 درصد) بر ویژگی های فراورده مورد نظر بر پایه آرد برنج با استفاده از طرح آماری سطح پاسخ بررسی شد. نتایج نشان داد که افزایش رطوبت منجر به افزایش سختی بافت، سختی بافت پس از غوطه وری در شیر، شاخص جذب آب و کاهش شاخص حلالیت در آب، شاخص روشنایی، شاخص قرمزی و شاخص زردی فراورده گردید. افزایش سرعت مارپیچ سبب افزایش شاخص حلالیت در آب، شاخص قرمزی، شاخص زردی و کاهش نسبت انبساط، سختی بافت پس از غوطه وری در شیر، شاخص جذب آب و شاخص روشنایی رنگ شد. افزایش میزان کنجاله کتان باعث افزایش میزان سختی بافت پس از غوطه وری در شیر، شاخص قرمزی و کاهش نسبت انبساط، شاخص روشنایی، شاخص زردی، شاخص جذب آب گردید، شاخص حلالیت در آب ابتدا کاهش سپس افزایش یافت. نتایج این پژوهش نشان می دهد استفاده از کنجاله کتان تا سطح 17 درصد به عنوان یک منبع غنی از فیبر رژیمی در فراورده های غله صبحانه اکسترود شده می تواند سبب تولید فراورده ای با ویژگی های تکنولوژیکی و حسی مطلوب گردد.

    کلیدواژگان: اکستروژن، آرد برنج، غله صبحانه، کنجاله کتان
  • عاصفه لطیفی*، محمدعلی کیه بادرودی نژاد، محمدرضا علیزاده صفحات 648-656

    غیریکنواختی در خشک کردن شلتوک با استفاده از خشک کن بستر خوابیده متداول درکارخانه های شالیکوبی یکی از عوامل موثر بر افزایش درصد شکستگی برنج و ضایعات در مرحله تبدیل محسوب می شود. به منظور بهینه سازی فرایند خشک کردن، یک دستگاه خشک کن بسترخوابیده مجهز به همزن و سیستم کنترل خودکار رطوبت شلتوک در مقیاس آزمایشگاهی طراحی و ساخته شد و کارایی آن مورد ارزیابی قرار گرفت. متغیرهای آزمایش، نوع خشک کن در دو سطح (مجهز به همزن و سیستم کنترل رطوبت (خشک کن هوشمند) و بدون همزن (رایج)) و نوع شلتوک در چهار سطح (طارم هاشمی، گوهر، طارم محلی و شیرودی) بودند. آزمایش به صورت فاکتوریل در قالب طرح کامل تصادفی در سه تکرار انجام شد. نتایج نشان داد، زمان خشک کردن شلتوک از رطوبت 2/14 درصد به رطوبت 5/8 درصد در خشک کن رایج به طور میانگین 1/43 ساعت و با خشک کن هوشمند 2/14 ساعت به طول انجامید. میانگین نرخ خشک کردن برای چهار رقم در خشک کن خوابیده 135/0 و در خشک کن هوشمند 412/0 درصد بر ساعت بوده است. اثر رقم بر راندمان تبدیل و راندمان برنج سالم (01/0<p) و اثر نوع خشک کن بر راندمان برنج سالم (05/0<p) معنی دار بود. بیشترین راندمان تبدیل و راندمان برنج سالم در رقم هاشمی (به ترتیب 2/69 و 7/87 درصد) و کمترین آن در رقم شیرودی (به ترتیب 2/62 و 8/57 درصد) به دست آمد. راندمان برنج سالم در خشک کن رایج به طور میانگین 9/67 درصد و در خشک کن هوشمند 2/73 درصد تعیین شد. نوع خشک کن تاثیر معناداری بر سفیدی رنگ ارقام نداشت. از بین چهار رقم فقط طارم هاشمی سفیدی رنگ بیشتری در خشک کن هوشمند نشان داد.

    کلیدواژگان: خشک کن شلتوک، درجه سفیدی، راندمان برنج سالم، نرخ خشک کردن
  • فرزانه اسمعیلی، مهناز هاشمی روان*، محمدرضا اسحاقی، حسن گندمی صفحات 657-679

    هدف از این تحقیق ریزپوشانی عصاره آبی ریشه گیاه باباآدم و استفاده از آن در نوشیدنی پروبیوتیک بر پایه آب پرتقال- هویج بود. برای این منظور ابتدا عصاره ریشه بابا آدم با دو روش میکروکپسولاسیون و نانوکپسولاسیون و با استفاده از دو ترکیب مالتودکسترین و صمغ عربی به عنوان پوشش دیواره، ریزپوشانی گردید. سپس عصاره ریزپوشانی شده (در سطوح 5/0 و 1 درصد) به همراه عصاره آزاد در فرمولاسیون نوشیدنی پروبیوتیک آب پرتقال- هویج استفاده و اثر آن بر زنده مانی باکتری های پروبیوتیک و همچنین ویژگی های فیزیکوشیمیایی و حسی محصول نهایی طی دوره نگهداری 30 روزه در دمای یخچال (°C 5/0± 4) مورد بررسی قرار گرفت. نتایج مرحله ریزپوشانی نشان داد که نانوکپسول ها دارای راندمان و محتوای فنلی بالاتری نسبت به میکروکپسول ها بودند (05/0>p)، بطوریکه بالاترین راندمان (75/92%) و سطح ترکیبات فنلی (mgGAE/g 385/0) و کوچک ترین اندازه ذرات کپسول (22/0± 33/14 میکرومتر) در نانوکپسول های تهیه شده با صمغ عربی مشاهده شد. تصاویر SEM نیز حاکی از این بود کپسول های تولیدی از لحاظ ریزساختار، دارای سطوح شیشه ای و زاویه دار بوده و شکل منظمی ندارند. با افزودن فرم های مختلف عصاره ریشه باباآدم به فرمولاسیون نوشیدنی پروبیوتیک آب پرتقال- هویج حاوی CFU/ml 108 باکتری لاکتوباسیلوس اسیدوفیلوس، مشاهد شد که پارامترهای کیفی از جمله عدد فرمالین، کدورت، ویسکوزیته، فعالیت آنتی اکسیدانی و بقاء باکتری های پروبیوتیک در نوشیدنی ها نسبت به نمونه کنترل افزایش یافت (05/0>p). طی دوره نگهداری در یخچال میزان کدورت، اسیدیته و IC50 در همه تیمارها به ویژه در نمونه کنترل افزایش یافت در حالی که سایرشاخص ها از جمله قابلیت زنده مانی باکتری های پروبیوتیک روند کاهشی نشان داد. افزودن فرم های مختلف عصاره ریشه باباآدم، تاثیر نامطلوبی بر طعم و بوی نمونه ها نداشت به طوری که کلیه تیمارها قابل پذیرش بودند. بنابراین، بر اساس نتایج این مطالعه می توان بیان کرد که عصاره ریشه باباآدم، به ویژه در قالب نانوکپسول، می تواند برای افزایش ماندگاری پروبیوتیک ها و افزایش فعالیت آنتی اکسیدانی غذاهای عملگرا طی فرایند تولید و نگهداری مورد استفاده قرار گیرد.

    کلیدواژگان: غذای عملگرا، عصاره باباآدم، سین بیوتیک، ریزپوشانی، عدد فرمالین
  • ساناز گل محمدزاده خیابان، فرید عمیدی فضلی* صفحات 681-697

    تلاش های گسترده ای جهت توسعه بسته بندی های بر پایه بیوپلیمرهای زیست تخریب پذیر و بهبود کارایی آنها صورت گرفته است. بیوپلیمرها که از منابع قابل تجدید کشاورزی حاصل می شوند جایگزینی مناسب برای پلاستیک های سنتزی به شمار می روند. اثر گلیسرول (%60- 20) به عنوان نرم کننده و نانوکریستال سلولز (%30- 0) به عنوان پرکن بر ویژگی های نانوکامپوزیت های ژلاتین- کربوکسی متیل سلولز مطالعه گردید. نانوسلولز مورد استفاده به روش هیدرولیز اسیدی تولید و توسط میکروسکوپ الکترونی روبشی و پراش اشعه ایکس مورد ارزیابی قرار گرفت. پس از تولید نانوکامپوزیت ها به روش تبخیر حلال آزمون های نفوذپذیری نسبت به بخار آب، حلالیت در آب، جذب رطوبت، زاویه تماس، خواص رنگی و خواص مکانیکی انجام یافت. فیلم های تهیه شده زمانی که از نانوسلولز کمتری استفاده شد نفوذپذیری کمتری نسبت به بخار آب از خود نشان دادند (gm/m2Pas11-10× 62/3 تا 12-10× 23/2) ولی غلظت های بالای نانوکریستال سلولز موجب افزایش نفوذپذیری نسبت به بخار آب می شود. با افزایش میزان گلیسرول به دلیل تشکیل پیوندهای جدید و از دسترس خارج شدن گروه های هیدروکسیل از مقادیر جذب رطوبت کاسته می شود البته در مقادیر پایین نانوکریستال سلولز وارد فضاهای خالی در ماتریکس فیلم شده و از حرکت آزادانه ملکول های آب ممانعت به عمل می آورد. همین طور نمونه های تولید شده مقادیر جذب رطوبت بالا داشتند و زاویه تماس متوسطی در حدود 60 درجه از خود نشان دادند. در سطوح ثابت نانوکریستال سلولز با افزایش مقدار گلیسرول زاویه تماس کاهش یافته است چرا که گلیسرول به عنوان یک ترکیب چند الکلی از خاصیت آبدوستی زیادی برخوردار است. اثر متقابل نانوسلولز و گلیسرول بر این ویژگی معنی دار است. در تیمارهای با سطوح پایین گلیسرول ازدیاد طول در نقطه شکست به زیر 5 درصد تقلیل یافته است. در خصوص استحکام کششی فیلم های حاصل از قدرت بالایی برخوردار هستند و حداکثر استحکام کششی 37/84 مگاپاسکال به دست آمد این مقدار در مورد تیماری است که از 40 درصد گلیسرول بدون افزودن نانوسلولز تهیه شده بود به دست آمد افزودن نانوسلولز به مقدار 4 درصد باعث کاهش جزیی در استحکام کششی می شود. رنگ نمونه ها مطلوب ارزیابی گردید. استفاده از گلیسرول به میزان 60 درصد و نانوسلولز به مقدار 4/4 درصد سبب تولید فیلم با ویژگی های مطلوب می شود. به کارگیری ژلاتین و کربوکسی متیل سلولز باعث تولید فیلم هایی گردید که از نظر نفوذپذیری نسبت به بخار آب و نم شوندگی سطوح نسبت به فیلم های خالص دارای ویژگی های بهبود یافته ای هستند.

    کلیدواژگان: ژلاتین، کربوکسی متیل سلولز، نانوسلولز، خواص آبدوستی، خواص مکانیکی
  • مصطفی رحمتی جنیدآباد*، بهروز علیزاده بهبهانی، محمد نوشاد صفحات 699-709

    در این مطالعه، اسانس انجدان رومی (Levisticum officinale Koch) توسط روش تقطیر با آب استخراج شد و سپس محتوای فنول تام، فلاونویید تام، فعالیت آنتی اکسیدانی (بر پایه مهار رادیکال آزاد DPPH، رادیکال آزاد ABTS و زوال رنگ بتا-کاروتن) و اثر ضدقارچی آن علیه قارچ های عامل پوسیدگی و فساد سیب و پرتقال (آلترناریا آلترناتا، پنی سیلیوم اکسپانسوم، پنی سیلیوم دیجیتاتوم، پنی سیلیوم ایتالیکوم و بوتریتیس سینه‏را) مطابق آزمون های ضدمیکروبی دیسک دیفیوژن آگار، چاهک آگار، حداقل غلظت مهارکنندگی و حداقل غلظت کشندگی مورد بررسی قرار گرفت. اسانس انجدان رومی به ترتیب حاوی mg GAE/g 34/0 ± 27/61 و mg QE/g 21/0 ±14/20 فنول و فلاونویید تام بود. فعالیت آنتی اکسیدانی آن بر پایه مهار رادیکال آزاد DPPH، رادیکال آزاد ABTS و زوال رنگ بتا-کاروتن به ترتیب 65/0 ±72/69 درصد، 3/0 ±54/78 درصد و 41/0 ±50/57 درصد بود. اسانس انجدان رومی در برابر تمامی گونه های قارچی تاثیرگذار بود و بیشترین حساسیت در مورد قارچ پنی سیلیوم اکسپانسوم مشاهده شد. مطابق نتایج، اسانس انجدان رومی را می توان به عنوان ضدقارچ طبیعی جهت جلوگیری از پوسیدگی و فساد میوه ها و سبزیجات پس از برداشت استفاده نمود.

    کلیدواژگان: انجدان رومی، اسانس، فعالیت آنتی اکسیدانی، اثر ضدقارچی، نگهدارنده طبیعی
  • آرمان نادری، سهیلا زرین قلمی* صفحات 711-723

    در پژوهش حاضر، اثر غنی سازی آرد گندم با آرد کنجد در نسبت های صفر، 5، 10 و 15 درصد بر ویژگی های آرد، خمیر و نان های سنگک و بربری بررسی شد. نتایج نشان داد که با افزایش میزان آرد کنجد، مقدار خاکستر و پروتیین آرد افزایش یافت، اما مقادیر رطوبت و گلوتن مرطوب کاهش پیدا کرد. به علاوه، شاخص های فارینوگرافی خمیر نظیر جذب آب و پایداری کاهش داشت، اما زمان گسترش و درجه نرم شدن خمیر افزایش یافت که بیانگر ضعیف شدن شبکه گلوتنی خمیر بود. نتایج اکستنسوگرافی نیز نشان داد که با افزایش میزان آرد کنجد، شاخص مقاومت به کشش نسبت به کشش پذیری کاهش پیدا کرد. بررسی نتایج ارزیابی سفتی بافت و رنگ نان ها نشان داد که افزودن آرد کنجد سبب کاهش سفتی بافت شد ولی اثر معنی داری بر شاخص های رنگی نان ها(L*, a* , b*)  نداشت. به علاوه ترکیب اسیدهای چرب نان ها نیز بهبود پیدا کرد. در نهایت در ارزیابی حسی، نان های سنگک و بربری به ترتیب حاوی 10 و 5 درصد آرد کنجد، بیشترین امتیاز پذیرش کلی را به دست آوردند.

    کلیدواژگان: آرد کنجد، بربری، سنگک، غنی سازی
  • شهاب نقدی، مسعود رضائی*، مهدی عبدالهی، مهدی طبرسا صفحات 725-738

    در مطالعه حاضر پلی ساکارید سولفاته از پوست ماهی قزل آلا توسط آنزیم پپسین استخراج شد و آنالیزهای FTIR، کربوهیدرات، سولفات، یورونیک اسید و پروتیین آن انجام شد. نتایج آنالیز شیمیایی پلی ساکاریدهای استخراج شده نشان داد که بازده استخراج 02/0 ±23/3% بود، همچنین درصد کربوهیدارت و پروتیین نمونه به دست آمده 56/2 ±03/57، 43/0 ±78/7 بود. همچنین مقدار سولفات و یورونیک اسید به ترتیب 77/0 ±54/6 و 43/0 ±86/3 بود. نتایج طیف سنجی مادون قرمز نشان داد یک پیک پهن در ناحیه 3350 تا cm-1 3450 مربوط به گروه -OH و باند خمشی سولفات S=O در ناحیه cm-1 1245 ظهور پیدا کرد. یک روند افزایشی و معنی دار در غلظت های مختلف مورد استفاده برای تست DPPH مشاهده شد (p<0.05) که بالاترین قدرت خنثی کنندگی (85/38%) در غلظت 2 میلی گرم/ میلی لیتر مشاهده شد. بالاترین درصد شلاته کنندگی رادیکال ABTS در غلظت 4 میلی گرم بر میلی لیتر آب مقطر با درصد (70/71%) مشاهده شد (p<0.05). نتایج شلاته کنندگی یون های فروزین پلی ساکارید استخراج شده نشان داد که بالاترین درصد شلاته کنندگی 43/98% بود (p<0.05). ظرفیت کف کنندگی، خواص پایداری کف و ظرفیت امولیسیون کنندگی نمونه مورد مطالعه حاکی از یک روند افزایشی با افزایش غلظت نمونه بود (p<0.05) و غلظت 10% پلی ساکارید سولفاته استفاده شده بالاترین درصد کف کنندگی (22/72%) و پایداری کف (22/62%) را از خود نشان داده است (p<0.05). خاصیت امولیسیون کنندگی پلی ساکارید سولفاته استخراج شده در برابر روغن سویا در تمامی غلظت های استفاده شده بیشتر از روغن آفتابگردان بود (p<0.05) و بالاترین مقدار این خاصیت مربوط به غلظت 10% با عدد 57/86% و 59/92% به ترتیب در برابر روغن آفتابگردان و روغن سویا بود (p<0.05).

    کلیدواژگان: ماهی قزل آلای رنگین کمان (Oncorhynchus mykiss)، پلی ساکارید سولفاته، ضداکسیدانی، کف کنندگی، امولیسیون کنندگی
  • مرجان زرگر، بهاره شعبان پور*، پرستو پورعاشوری، ابراهیم ذبیحی نیشابوری صفحات 740-749

    کلاژن فراوان ترین و مهم ترین پروتیین ساختاری در بافت همبند جانوران است که تولید آن اهمیت زیادی در زمینه های پزشکی و دارویی، آرایشی- بهداشتی و غذایی دارد. با توجه به محدودیت های مذهبی و نیز بیماری های مشترک بین دام و انسان، امروزه استحصال کلاژن به دیگر منابع و به ویژه منابع آبزی معطوف شده است. بنابراین هدف این مطالعه استخراج کلاژن به دو شیوه مرسوم اسیدی و آنزیمی از فلس کپور معمولی و تعیین ویژگی های آن به منظور استفاده بهینه از این پسماند برای تولید محصولات با ارزش افزوده و یافتن جایگزینی برای کلاژن به دست آمده از حیوانات خشکی می باشد. کلاژن محلول در اسید (Acid soluble collagen) و کلاژن محلول در پپسین (Pepsin soluble collagen) از فلس کپور معمولی (Cyprinus carpio) استخراج و خواص آنها تعیین شد. فلس های کپور معمولی پس از آماده سازی به کمک اسیداستیک 5/0 مولار و آنزیم پپسین تحت استخراج قرار گرفته در نهایت کلاژن استخراج شده، لیوفیلیزه شد و پس از محاسبه بازده استخراج، ویژگی های آن با استفاده از آزمون های الکتروفورز، طیف سنجی فرابنفش، پراش اشعه ایکس و تعیین نقطه ایزوالکتریک مورد بررسی قرار گرفت. یافته ها نشان داد که بازده استخراج ASC و PSC به ترتیب 9/1% و 96/2% (بر مبنای وزن خشک) بود یعنی هضم با پپسین می تواند تا 54/1 برابر باعث افزایش بازده کلاژن شود. نتایج آنالیز SDS-PAGE نشان داد هر دو ASC و PSC به عنوان کلاژن نوع I بوده و ازα1 ، α2 و β در ساختار زنجیره ای (α1)2α2 تشکیل شده اند؛ نقطه ایزوالکتریک کلاژن ها در دامنه pH 5- 6 قرار داشت. حداکثر پیک جذب طیف فرابنفش کلاژن های به دست آمده در 235 نانومتر مشاهده شد. اگرچه آنزیم پپسین (1% وزن خشک فلس) باعث افزایش بازده بدون تغییر معنی دار در ساختار کلاژن می شود ولی استفاده از آن برای تولید انبوه کلاژن نوع I در ایران تا رسیدن به خودکفایی و کاهش قیمت پپسین، توصیه نمی شود این درحالیست که استخراج کلاژن به روش اسیدی بسیار ساده بوده و تحقیق جهت طراحی خط تولید برای این روش پیشنهاد می شود. فلس کپور معمولی این پتانسیل را دارد که به عنوان منبع جایگزین کلاژن در صنایع غذایی و بهداشتی- دارویی به کار رود. این نتایج می تواند علاوه بر تولید محصول با ارزش افزوده بالا از فلس کپور معمولی، راهکاری برای کنترل ضایعات صنعت فرآوری آبزیان در ایجاد آلودگی محیط زیست ارایه دهد.

    کلیدواژگان: فلس، کپور معمولی (Cyprinus carpio)، کلاژن محلول در اسید، کلاژن محلول در پپسین، ضایعات
  • زهرا صدری صائین، محمدرضا خانی*، وجیهه فدائی نوغانی صفحات 751-763

    کره به عنوان یک نوع فرآورده لبنی، از خامه شیرین یا خامه ترش تهیه می شود که می تواند به دلیل تغییرات اکسیداتیو دچار فساد شود. این تحقیق با هدف بررسی اثرات آنتی اکسیدانی عصاره دانه چیا در کره حاصل از خامه شیرین جهت بهبود ویژگی های شیمیایی (اسیدیته، عدد اسیدی، عدد پراکسید و اسید تیوباربیتوریک) و حسی (رنگ، بو، طعم، بافت و پذیرش کلی) آن طی دو ماه نگهداری در یخچال انجام گردید. ابتدا عصاره الکلی دانه چیا تهیه و میزان پلی فنول کل و فعالیت آنتی اکسیدانی آن ارزیابی گردید و سپس با درصدهای مختلف (05/0، 1/0، 25/0 و 5/0) به کره افزوده شد و اثرات آن بر ویژگی های کره ارزیابی شد. نتایج مقدار پلی فنول کل حدود 79/111 ±78/1108 میلی گرم اسید گالیک بر 100 گرم عصاره و قدرت مهارکنندگی عصاره دانه چیا در محدوده غلظت 20- 4 درصد، 47/0 ±17/35 تا 95/2 ±92/64 درصد به دست آمد. نتایج نشان داد با افزایش میزان عصاره دانه چیا در کره، میزان اسیدیته و عدد اسیدی به طور معنی داری نسبت به نمونه شاهد افزایش و عدد پراکسید و اسید تیوباربیتوریک کاهش یافت (05/0>p). همچنین تمامی این شاخص های شیمیایی با افزایش مدت زمان نگهداری به طور معنی داری افزایش یافتند (05/0p<). تمامی نمونه ها از نظر ویژگی های حسی (به استثنای بو) در طول 60 روز نگهداری با نمونه شاهد تفاوت معنی داری داشتند (05/0p<)، به طوری که تیمارها از امتیازات رنگ و طعم بهتری نسبت به شاهد برخوردار بودند. به طور کلی غلظت 5/0 درصد عصاره چیا باعث به تعویق انداختن فساد اکسیداتیو گردید اما از نظر ارزیابی حسی، تیمار حاوی 25/0 درصد عصاره چیا به عنوان تیمار برتر انتخاب و معرفی می گردد.

    کلیدواژگان: عصاره دانه چیا، کره، فعالیت آنتی اکسیدانی، ویژگی های شیمیایی، ویژگی های حسی
  • حامد صابریان*، وحید پاسبان صفحات 765-777

    آنتوسیانین ها یکی از مهمترین رنگدانه‎های غذایی هستند که کاربرد گسترده‎ای در محصولات غذایی دارند. یکی از منابع مستعد آنتوسیانین در ایران، گلبرگ زعفران می‎باشد. پایداری حرارتی نسبتا پایین آنتوسیانین‎ها موجب استفاده بیشتر از رنگ‎های سنتزی شده است.  هدف این پژوهش، بررسی تاثیر سیکلودکسترین ها و کوپیگمانتاسیون بر پایداری عصاره آنتوسیانینی استخراجی از گلبرگ زعفران در برابر تیمار حرارتی بود. از غلظت‎های مختلف آلفا و بتاسیکلودکسترین (10، 25، 50، 75 و 100 مول آلفا/ بتاسیکلودکسترین به ازای 1 مول آنتوسیانین) و همچنین از کوپیگمان‎های مختلفی ازقبیل گالیک اسید (در دو نسبت مولی 50 به 1 و 100 به 1 نسبت به آنتوسیانین)، فرولیک اسید (در دو نسبت مولی 50 به 1 و 100 به 1 نسبت به آنتوسیانین)، کویرستین (در دو نسبت مولی 5/2 به 1 و 5 به 1 نسبت به آنتوسیانین) و روتین (در دو نسبت مولی 10 به 1 و 25 به 1 نسبت به آنتوسیانین) و عصاره نسترن کوهی (در دو نسبت مولی 50 به 1 و 100 به 1 معادل گالیک اسید به آنتوسیانین) برای بررسی پایداری حرارتی آنتوسیانین‎ها استفاده شد. نتایج حاکی از آن بود که آلفاسیکلودکسترین تاثیر معنی‎داری در سطح اطمینان 95 درصد (05/0 <p) بر پایداری آنتوسیانین نداشت اما بتاسیکلودکسترین در نسبت مولی 50 به 1 (بتاسیکلودکسترین به آنتوسیانین) موجب افزایش پایداری رنگدانه شد. اگرچه ترکیبات فنولی تاثیری در پایدارسازی حرارتی آنتوسیانین‎های نوشیدنی مدل نداشتند اما عصاره نسترن کوهی در هر دو نسبت مولی 50 و 100 به 1 موجب افزایش معنی‎دار بقاء آنتوسیانین‎ها شد. بنابراین، بتاسیکلودکسترین به عنوان یک ترکیب پوشاننده و عصاره نسترن کوهی به عنوان یک ترکیب کوپیگمان می‎توانند موجب افزایش پایداری آنتوسیانین گلبرگ زعفران طی تیمار حرارتی شوند.

    کلیدواژگان: پایدارسازی حرارتی، آنتوسیانین، گلبرگ زعفران، بتاسیکلودکسترین، عصاره نسترن کوهی
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  • Sara Shahryari, Alireza Sadeghi *, Maryam Ebrahimi, Alireza Sadeghi Mahoonak, Ali Moayedi Pages 575-588
    Introduction

    Evaluation of antimicrobial and probiotic properties of the microbiota isolated from fermented pseudo-cereals is important in order to prepare adjunct and starter cultures. Probiotics are live and active microorganisms that, if used in sufficient numbers, help the microbial balance of the gastrointestinal tract and improve its function. Probiotics are also used as a substitute for antibiotics and synthetic preservatives in the prevention and treatment of complications of many infectious and pathogenic gastrointestinal pathogens. Probiotic microorganisms include lactic acid bacteria (LAB) and yeasts, and despite numerous reports on the probiotic properties of LAB, the probiotic properties of yeasts are less reported. Probiotic yeasts are organisms resistant to antibacterial compounds and effective against pathogens, which can rapidly increase their population in the gastrointestinal tract. These yeasts have several properties such as antimicrobial effects, resistance to acid and bile, binding to mucosal surfaces, inhibitory activity against pathogens and also the inability to transmit antibiotic resistance genes. In the present study, after isolation of the predominant yeast from buckwheat sourdough, the probiotic and antifungal properties of the isolate were investigated. Based on the literature review, no study has been presented to evaluate the probiotic and antifungal capabilities of yeasts isolated from buckwheat sourdough. 

    Materials and Methods

    In the present study, predominant yeast was isolated from buckwheat sourdough, and then it was identified using PCR. Subsequently, probiotic properties of the isolate including survival in present of low pH and bile salt, antibacterial effect, antibiotic susceptibility assay, aggregation, hydrophobicity, haemolytic activity as well as its antifungal activity against Aspergillus niger and Aspergillus flavus were studied. After spontaneous fermentation of buckwheat, predominant yeast was isolated using ten-fold dilution of the sourdough sample and its spread plating. The predominant isolate was identified through PCR amplification of a 650 bp target sequence from its ribosomal gene and sequencing of the PCR product. Then, survival of the yeast was determined at pH=2 and 0.3% bile salt as simulated gastrointestinal conditions. Subsequently, simultaneous culture of the yeast with some food-borne indicator bacteria in chromogenic media was used to investigate the inhibitory activity of the isolate against the studied bacteria. After that, resistance of the yeast isolate against the common antibiotics and some antimycotic agents was evaluated using disc method. Co-aggregation ability and hydrophobicity capability of the isolate were also determined based on the absorbance tests. In vitro safety of the yeast isolate was checked through its cultivation on blood agar containing sheep blood. Next stage, overlay bioassay was conducted to investigate antifungal effect of the yeast on the selected fungi. Finally, one way analysis of variance (ANOVA) with the least significant differences (LSD) post hock at p<0.05 was used for statistical analysis of the data. 

    Results and Discussions

    Sequencing results of the PCR products led to the identification of Pichia kudriavzevii as predominant yeast isolated from buckwheat sourdough. Survival rate of the isolate after treatment in simulated gastrointestinal conditions was 79.26% in comparison with the control. Antibacterial effect of the isolate on Escherichia coli was also significantly (P<0.05) higher than the other studied food-borne agents. Meanwhile, the growth of Listeria monocytogenes was decreased 19.50% in the present of the isolate. Whereas, the yeast isolate had no inhibitory effect on Salmonella enterica. Hydrophobicity and auto-aggregation capabilities of the isolate were also 64.07 and 67.40%, respectively. Furthermore, the isolate showed resistance towards all of the antibiotics tested, while it was resistant against ketoconazole and fluconazole, and the yeast was semi-sensitive towards itraconazole as antimycotic agents. The yeast isolate had no hemolytic activity, and its antifungal activity against A. niger and A. flavus was also verified. Accordingly, it is concluded that P. kudriavzevii isolate exhibits proper potential to be used as probiotic or protective culture in fermentation industries.In accordance with the results, probiotic characteristics of P. kudriavzevii (as the predominant yeast isolated from buckwheat sourdough) were approved. Accordingly, the isolate can be used as a potential probiotic culture in food industries.

    Keywords: Yeast isolate, Buck wheat sourdough, probiotic properties, antifungal effect
  • Kobra Tajik Toughan, Mohammad Reza Edalatian Dowom *, Seyed Ali Mortazavi, Ali Javadmanesh Pages 589-601
    Introduction

    Poultry and meat products are the largest sources of non-typhoid salmonella infections in most countries. Studies have shown that raw foods of animal origin, especially poultry and its products, are the main source of contamination of kitchens and restaurants. In terms of growth conditions, these microorganisms are resilient bacteria and easily adapt to their environmental conditions. Salmonella has been known to cause intestinal disease for many years and has been reported as the most important cause of food poisoning. According to Iranian and international standards, there should be no S. enteritidis or S. typhimurium in 25 grams of food. DNA-based methods for the identification and differentiation of Salmonella serovars have been designed and applied using specific primers at the genus and serovar levels. Therefore, they can be used as useful and rapid screening tests, as well as to supplement or replace conventional biochemical and serological tests. Real-time PCR, with the most accurate and reliable results using a fluorescence probe, which of course has a high cost. In this method, sequence specific fluorescence probes are used, and as a result, in the target molecule, screening and determination the presence or even the concentration of specific sequences is possible. Therefore, even in the presence of other types of nucleic acid molecules, the results are obtained quickly and have a high level of specificity. Under these conditions, if specific probes with different florescence dyes are used, even multiple targets can be detected in a single PCR reaction. The aim of this study was to identify S. enteritidis or S. typhimurium by PCR and Salmonella spp. by real time PCR method in poultry products. 

    Material and Method

    In total, 45 samples of poultry products, including chicken breast, liver and gizzard (15 samples each) were purchased from different regions of Mashhad and from various companies and transferred to the laboratory in accordance with hygienic standards. For each sample, 25 g of tissue was isolated and homogenized under sterile conditions and DNA extraction was then performed using a DNA extraction kit. The extracted DNA was evaluated by agarose gel electrophoresis. The purity and quantity of DNA extracted from each sample was examined by spectrophotometry method. In the next step, in order to identify the genus Salmonella, the samples were examined by real time PCR. In this method we used an internal control to ensure that negative results are not false negative due to inhibitors. The results of real time PCR showed that out of 45 samples, nine samples were infected with Salmonella. Then, these nine samples were evaluated for Salmonella typhimurium and Salmonella enteritidis infection by conventional PCR method. 

    Result and Discussion

    The results showed that out of nine samples that were positive in real time PCR test, seven samples were contaminated with Salmonella typhimurium, of which five samples were related to chicken breast and two to liver. Regarding Salmonella enteritidis infection, out of nine samples, only one sample was contaminated, which was related to chicken breast. Conventional methods have been traditionally used to enumerate target bacteria in food. However, these methods have some limitations and require considerable time and labor. Previous studies have already shown that real time PCR is more effective than conventional bacteriological methods for the detection of Salmonella spp. In a study by Whyte et al. (2002) The presence of Salmonella was assessed by traditional culture methods and by a Salmonella-specific polymerase chain reaction (PCR) test. Salmonella was recovered from 16% of samples using traditional culture methods. In contrast, the PCR assay proved to be more sensitive and detected Salmonella DNA in 19% of the examined samples (Whyte et al. 2002). Results of PCR with specific primers showed that reactions in real time PCR with general primers of Salmonella spp. were done correctly. Despite of accuracy and speed of real time PCR to detect DNA of microorganisms, further studies are developed to have more advantages. Loop-mediated isothermal amplification (LAMP) showed a higher sensitivity of Salmonella detection in compare to qPCR (Vichaibun & Kanchanaphum, 2020). Although LAMP could detect trace amount of Salmonella DNA but primer design for this reaction is very difficult. However, it is important to highlight that non-viable cells can be detected by real time PCR or other DNA-based methods, which does not occur in traditional methods of culture and isolation that require viable cells for quantification (Zeng et al., 2016).

    Keywords: Salmonella Typhimurium, Salmonella enteritidis, chicken breast, Real time PCR
  • Behrooz Alizadeh Behbahani *, Mohammad Noshad, Mostafa Rahmati-Joneidabad Pages 603-614
    Introduction

    Oxidation and food pathogens are considered two important and influential factors affecting food quality and health. Recently, due to the increasing demand for natural products, the application of synthetic preservatives to control microbial growth and lipid oxidation have been decreased significantly. Therefore, natural antioxidant and antimicrobial compounds are receiving more attention in food preservation technologies. In the last 2 decades, the use of herbal medicines rich in bioactive molecules (including polyphenols, carotenoids and flavonoids) with medicinal and health effects such as delaying the onset of some diseases such as cardiovascular disorders, diabetes, and cancer have increased. Furthermore, secondary metabolites in plant extracts and essential oils are able to control and inhibit free radical-mediated reactions. The olive tree (Olea europaea) is an evergreen plant that grows in tropical and subtropical regions. Iran is one of the most important olive growers in the world due to its suitable conditions for olive cultivation. The leaves of the olive plant have a high potential for the production of various products such as tea and extracts. Olive leaf extract can be used as a raw material in the production of various products, due to exhibiting various biological activities such as antimicrobial and antiviral activity, lipid stabilizer, blood pressure regulator, antioxidant activity, and free radical scavenger. The leaves of the olive tree also contain various phenolic compounds, mainly Oleuropein and hydroxytyrosol, with antioxidant and antimicrobial activities. Therefore, in this study, the amount of phenolic and flavonoid compounds of olive leaf ethanolic extract and its antioxidant effect and antimicrobial properties on Escherichia coli, Enterobacter aerogenesis, Bacillus cereus and Listeria innocua were investigated. 

    Materials and Methods

    The olive leaf ethanolic extract was prepared through maceration method and its total phenolic content (Folin-Ciocalteu method), total flavonoids content (aluminum chloride colorimetric assay), antioxidant activity (ABTS and DPPH free radical scavenging methods), and antimicrobial effect on E. coli, E. aerogenesis, B. cereus and L. innocua (based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration) were determined according to standard methods. Data were analyzed by SPSS software through one-way ANOVA and Duncan test at p<0.05.  

    Results and Discussion

    The ethanolic extract of olive leaves contained 176.58 ± 0.72 mg GAE/g total phenol and 69.85 ± 0.26 mg QE/g total flavonoids. In addition, ethanolic extract of olive leaf was able to inhibit free radicals DPPH (70.62 ± 0.59%) and ABTS (76.15 ± 0.43%). The antimicrobial results showed that the antimicrobial effect of the extract depended on its concentration and type of bacteria. Antimicrobial effect was increased as a function of ethanolic extract, and Gram-positive bacteria (B. cereus and L. innocua) were more sensitive to ethanolic extract of olive leaf than Gram-negative bacteria (E. aerogenesis and E. coli). Generally, B. cereus and E. aerogenesis were the most sensitive and resistant microbial strains to ethanolic extract of olive leaf, respectively.The results of this study showed that the high antioxidant and antimicrobial activity of olive leaf ethanolic extract is mainly due to its phenolic and flavonoid compounds. Olive leaf ethanolic extract was able to neutralize DPPH and ABTS free radicals. Also, Gram-positive bacteria were more sensitive to ethanolic extract of olive leaf than Gram-negative bacteria. In general, the ethanolic extract of olive leaf can be used as a nutraceutical to control or prevent the growth of spoilage/infection-causing microorganisms and free radical reactions in food and the human body. However, more in-depth studies are needed to determine the mechanism of antimicrobial and antioxidant effects of olive ethanolic extract in vitro and in vivo.

    Keywords: Olive leaf, Ethanolic extract, Antimicrobe, Antioxidant, Natural preservative
  • Saeid Azizkhani, Leila Nateghi * Pages 615-630
    Introduction

    Nowadays, production and consumption of functional and dietary foods have increased. Today, the medicinal, antibacterial and antioxidant properties of fungi have been proven. Ganoderma lucidum is one of the fungi that has been known as the best medicinal fungus due to its various health benefits. Ganoderma lucidum is an annual medicinal fungus which belongs to the Ganodermataceae family. G. lucidum also known as Reishi in Japan, Ling-zhi in China, Ling chih, and Ling chi mushroom in other countries. It is popular among consumers in Japan and is widely used by Asian physicians and herbalists. This medicinal mushroom has been used in Asia for thousands of years to increase energy, stimulate the immune system, and promote health and longevity. In the US, G. lucidum is included in the American Herbal Pharmacopoeia and usually recommended for its immune-supporting effects. In Poland and other countries outside Asia, G. lucidum is used as a daily food supplement that adapts itself to correct imbalances in the body. Influenced by an increasing number of studies on G. lucidum, modern application of G. lucidum include but not limited to treatment of coronary heart disease, arteriosclerosis, hepatitis, arthritis, nephritis, bronchitis, hypertension, cancer and gastric ulcers. The major chemical constituents of G. lucidum are polysaccharides, triterpenes, sterols, lectins and some proteins having beneficial properties for the prevention and treatment of a variety of ailments. Both triterpenes and polysaccharides contain anticancer properties thus making them important nominees for the researches. Spores, fruiting body and mycelium have been investigated for biological active compounds. Ganoderma lucidum is a kind of mushroom known to have various therapeutic properties such as lowering high blood sugar and high blood pressure, boosting the immune system as well as its antibacterial and antioxidant effects.In recent years, a number of researches were performed for the identification of biological compounds and medicinal properties of Ganoderma lucidum. 

    Materials and Methods

    In this study, baguette bread with 0.5, 1, 1.5, 2 and 2.5 % Ganoderma lucidum powder was used in baguette bread formulation. The aim of this study was to investigate the possibility of enriching baguette bread using Ganoderma lucidum and to investigate the physicochemical, rheological, texture analysing, microbial, stale and sensory evaluation properties. Therefore, 5 treatments were designed with a control treatment and tests were performed on the treatments in three replications. In order to analyze the data, one-way ANOVA analysis of variance and Duncan at 95% confidence level were used in Minitab 16 software. 

    Results and Discussion

    Examination of the rheological properties of the dough showed that different percentages of Ganoderma lucidum significantly affect the rheological characteristics of the dough (p≤0.05) and addition of  Ganoderma lucidum reduced the above indices. According to the results, addition of Ganoderma lucidum caused a significant increase (p≤0.05) of phenolic compounds and fiber in bread samples. The results of microbial evaluation showed that with increasing Ganoderma lucidum level in baguette bread, the number of coliforms and molds in the treatments decreased significantly (p≤0.05). The results of sensory evaluation showed that the increase of Ganoderma lucidum level in baguette samples caused a slight decrease in taste, color, odor and general acceptance compared to the control sample.Fungi are rich in protein, pigment, carbohydrates, fatty acids, vitamins and minerals that can be used in food enrichment. Due to the growing human tendency to use natural substances, fungi can be a suitable source to meet this need. According to the results, up to 2.5 % of Ganordama lucidum can be added to baguette bread formula and higher fiber content, more phenolic compounds, more freshness, less microbial load in baguette bread were obtained without having an adverse effect on its sensory properties. Therefore, the treatment mentioned in this study was selected as the best treatment in terms of safety, health and quality properties.

    Keywords: Ganoderma lucidum, Enrichment, Baguette, Phenolic compounds
  • Alireza Abbasi, Arash Koocheki, Elnaz Milani *, Mohebbat Mohebbi Pages 631-647
    Introduction

    Breakfast cereal products are considered as an important meal for athletes and children. By changing eating habits and increasing the consumption of these products, choosing healthy and nutritious raw materials such as whole grains to produce breakfast cereals with great impact on people's health. Rice grain as a technologically important source of starch causes the expansion of extruded products. Since in the production of breakfast cereal and baby food products, exclusively starch with low amylose is used, this indicates the suitability of this source for productionof such products. During the dehusking process, about 14% of the rice is broken to smaller grains, which is commercially classified as a low-value product. The broken rice can be converted to rice flour and used as a raw material in various types of food products. To maintain consumer demand for healthy diets, it is necessary to use high-fiber flours because these types of products will be able to modify the process of decomposition of starch. Although the integration of fiber in products has technological challenges, but by using rice grain as an important source of starch, the technological properties, expansion index, volumetric density and texture (texture hardness and brittleness) can be accepted. At present, modified starch derivatives are widely used in the food industry due to the increase in the quality of the final product. In the production of ready-to-use products for flaking, puffing, a process called extrusion is used. In this process, the product suddenly loses its moisture and leads to the creation of a dense structure containing pores. In this study, the effect of extrusion cooking process parameters on the desired characteristics of flax and rice meal breakfast cereal product with desirable physicochemical and sensory properties was investigated. 

    Materials and Methods

    Extrusion: In this study, a parallel twin-screw extruder (Jinan Saxin, China) was applied, die diameter of 3 mm, and extrusion temperature of 140 ℃. Central composite statistical design was used to study the effect of feed moisture (12, 15 and 18%), screw speed (140, 170 and 200 rpm) and Flaxseed oil cake addition (10, 20 and 30%) on technological and functional properties expanded extrudates. The chemical composition of flax meal and rice flour was measured by standard AACC (2000) methods. The expansion ratio was calculated by dividing the mean diameter (mm) by the diameter of the extruder die (4 mm) (Brennan et al, 2008). Textural measurement: The hardness of the extruded breakfast cereals was measured using Texture Analyzer (TA plus Ametek, UK). The cylinder steel probe (2 mm diameter) was set to move at a speed of 1 mm/s The samples were punctured by the probe to a distance of 10 mm. Bowl life hardness: Breakfast cereal samples were immersed in whole milk (3% fat) at 5 ° C for 3 minutes, Then rinsing was performed for 10 seconds and finally the samples were tested similar to the tissue hardness test procedure before immersion by a tissue analyzer (Oliveira et al, 2017). The color parameters L* (lightness), a*(redness), b*(yellowness) values of the samples were determined by the Hunterlab machine (Reston VA, US) (Rhee et al, 2004). Water absorption index in terms of grams of bonded water was calculated. The WSI of the dry solids regained through the evaporation of the supernatant obtained from the water absorption test was calculated (Alam et al, 2019). Sensory evaluation was performed using a 9-point hedonic test. Response surface methodology was applied for experimental data using a commercial statistical package, Design Expert (version 7.0) for the generation of response surface plot and statistical analysis of the experimental data. 

    Results and Discussion

    One of the most important parameters in the evaluation of breakfast cereal products is the amount of bowl-life hardness, which in this study, the highest amount was obtained at the level of 30% of flaxseed meal, 18% moisture and the lowest amount of screw rotation speed. After immersing breakfast cereal in milk, by increasing the percentage of flax meal due to the harder flow path, moisture absorption decreases and thus prevents the expansion of the product and increases the density of the mass and the hardness of the tissue. Due to the formation of a layer of lipids and micelles on the surface of the product prevents moisture transfer and absorption, so tissue hardness decreases and bowl-life hardness time increases. In fact, the amount of moisture absorption is a good model that shows the potential of bowl hardness-life of the samples. It is also compact and dense, which increases the retention time of breakfast cereal texture. Moisture can also reduce the shear force as a plasticizer and increase the amount of moisture absorption of the product. While increasing the speed of screw rotation, the effect of shear force on starch dextrinization increases and reduces moisture absorption. Another important feature of breakfast cereals is the lightness index, the highest value of which was obtained at the speed of screw rotation, humidity and low flax meal level. In the study of sensory properties of products produced at meal levels less than 20%, moisture content less than 15% and screw speed of 200 rpm showed the highest overall acceptance.

    Keywords: Extrusion, Rice flour, Breakfast cereal, Flaxseed oil cake
  • Asefeh Latifi *, Mohammadali Kiehbadroudinezhad, MohamadReza Alizadeh Pages 648-656
    Introduction

    Non-uniformity of dried paddy using conventional batch type dryer is one of the important factors on rice breakage and losses in milling operations in Iran. For optimizing drying process, a laboratory batch type paddy dryer with agitator and automatic moisture controller was designed and fabricated. The performance of the dryer was evaluated after fabrication. 

    Materials and Methods

    The experimental variables were dryer type in two levels (batch dryer with agitator and batch dryer without agitator) and paddy variety in four levels (Hashemi, Gohar, Tarom and Shirodi). The time of drying, drying rate, milling yield, head rice yield, track percentage and whiteness, was conducted in factorial layout based on completely randomized design with three replications. 

    Results and Discussion

    The results obtained revealed that the drying time from initial paddy moisture content (average of 14.2 %) to final moisture content (about 8.5 %) lasted about 14.2 h and 43.1 h in batch dryer with and without agitator, respectively. The average drying rate in batch dryer without agitator for all varieties was 0.135%.h-1 and that of the batch dryer with agitator was 0.412%.h-1. There was a significant effect of dryer type on milling recovery and head rice yield (P<0.01) of different variety (P<0.05). The highest milling recovery and head rice yield was determined in Hashemi (69.16 and 87.66 %, respectively) and the lowest corresponding values were registered in Shirodi (62.16 and 57.83 %, respectively). The head rice yield in batch dryer without and with agitator was found to be 67.91 % and 73.16 %, respectively. There was non-significant difference between percentages of track in two types of dryers. The rice whiteness of Hashemi variety dried with batch dryer with agitator (50.46 %) was significantly (P<0.01) higher than the rice whiteness in batch dryer without agitator (46.10 %), however there was non-significant difference between the means of rice whiteness in the other paddy varieties in the two tested dryers.Fabrication and installation of dryer with agitator and automatic moisture controller has benefit of saving time of drying to one third and increasing head rice yield to 5% compare with traditional paddy dryer

    Keywords: Paddy dryer, Drying rate, Head rice yield, whiteness
  • Farzaneh Esmaeili, Mahnaz Hashemiravan *, MohammadReza Eshaghi, Hassan Gandomi Pages 657-679
    Introduction

    Nowadays, there is a great tendency to consume functional foods, with special medicinal and extranutritional value in addition to basic nutritional properties. Foods containing probiotics and prebiotic compounds are classified in this category. Inulin is a water soluble storage polysaccharide and belongs to a group of non-digestible carbohydrates called fructans. Inulin is naturally present in some flowering plant species such as chicory and burdock root. The amount of inulin in these plants is in the range of 1 to 20% of the weight of the fresh plant. Pharmacological studies report that Burdock root contains significant amounts of the inulin as a prebiotic compounds, also exhibits a wide range of biological activities, specifically antioxidative, anti-inflammatory, and free radical scavenging activities. The aim of this study was to encapsulate the aqueous extract of burdock root and use it in a probiotic drink based on orange-carrot juice. 

    Material and Method

    The Burdock roots were obtained from the local medical plant market, Tehran, Iran. Orange and carrot juice were purchased from Nooshin and Tandis (Food Company, Tehran, Iran) respectively. Maltodextrin and gum Arabic were prepared from Merck, Germany. First, the plant roots were dried to 5.2% moisture and then its aqueous extract was extracted with the help of ultrasonication. Then burdock roots extracts were encapsulated by spray drying (microencapsulation) and freeze drying (nanocapsulation) using maltodextrin and gum Arabic as wall coating agents. Capsule properties including encapsulation efficiency, particle size distribution, moisture, density, structural properties, TPC and antioxidant were determined. Then the encapsulated extracts (at levels of 0.5 and 1%) and free extract were used in the formulation of probiotic orange-carrot juice and its effect on the survival of probiotic bacteria as well as physicochemical and sensory properties of the final product during 30 days in refrigerator (4±0.5 °C) were investigated. All experiments were carried out based on complete randomized design and the results represent the mean of at least three replicates. The data obtained were analyzed by the analysis of variance (ANOVA) using Minitab 16.0 statistical software. Significant differences between means were determined by Duncan’s multiple range test at a probability levels of P≤0.05. 

    Results and Discussion

    The results of encapsulation phase showed that Nanocapsules had higher efficiency and phenolic compounds content than microcapsules. The highest level of efficiency (92.75%) and phenolic compounds (0.385 mg GAE/g) and the smallest capsule particle size (14.33±0.22 µm) were observed in Nanocapsules prepared with gum Arabic. The SEM images showed that the produced capsules in terms of microstructure, had flaky/glassy and angular surfaces and did not have a regular shape. By adding different forms of the extract (free/micro/Nano) to the orange-carrot juice, it was found that its characteristics including viability of probiotics, formalin index, turbidity, viscosity and antioxidant activity were significantly enhanced during cold storage compared to the control (p<0.05). During refrigeration, turbidity, acidity and IC50 increased in all treatments, especially in the control sample, while other characteristics (including the viability of probiotic bacteria), showed a decreasing trend. Addition of different forms of burdock root extract did not have an adverse effect on the flavor and odor of the samples, so that, all treatments were acceptable. Therefore, based on the results of this study, it can be stated that encapsulated burdock root extracts, especially in the form of nanocapsulation, can be used to increase the viability of probiotics and enhancement the antioxidant activity of functional foods

    Keywords: functional food, Encapsulation, burdock root extract, Synbiotic, formalin index
  • Sanaz Golmohammadzadeh, Farid Amidi-Fazli * Pages 681-697
    Introduction

    The biodegradability of synthetic plastics derived from petroleum is a very slow process and complete decomposition of them lasts several years. This increases environmental pollution. Extensive efforts have been made to develop and improve biopolymers-based packaging. Biopolymers derived from renewable agricultural resources are an appropriate alternative to synthetic plastics. The use of nanotechnology in the field of polymer science has led to the production of nanocomposite polymers. The valuable nanocomposites would be produced if natural nanoparticles are used in composites preparation. Because of the importance of nanocomposites in the production of biodegradable films and due to desired properties of gelatin and carboxymethyl cellulose in film production, this study aimed to investigate the effect of glycerol and nanocellulose on the properties of gelatin-carboxymethyl cellulose nanocomposites. 

    Materials and Methods

    To prepare 12 different treatments based on statistical design, 1 g of gelatin and 1 g of carboxymethylcellulose were dissolved in distilled water to form a uniform solution. Then, glycerol as a plasticizer was added to the prepared solutions at different levels (20 to 60% w/w). The determined amount of nanocellulose (0- 30% w/w), based on the biopolymers weight, was added to the cooled blend at 70°C. Nanocellulose was extracted from cotton through the chemical method, cotton was gone under chemical hydrolysis by the sulfuric acid solution (65% w/v). The properties of gelatin-carboxymethylcellulose nanocomposites were studied. The produced nanocellulos evaluated by scanning electron microscopy and X-ray diffraction techniques. The thickness of the films was measured using a caliper with a precision of 0.01. At five different parts of each film. Water vapor flux and water vapor permeability through the film samples were determined. The dry matter of 20× 20 mm film samples before and after immersion in 50 ml of distilled water for 24h at 25 °C was determined to calculate the solubility in water of the films. To measure the moisture absorption of the nanocomposite samples, 20× 20 mm film pieces were kept in a container containing potassium sulfate saturated solution (RH= 97%) at 25°C for 4 days. Films were weighted initially and at the end of the experiment. Sessile drop method, a common technique for determining the wetting properties of solid surfaces, was then used to determine the contact angle. Ultimate tensile strength and elongation at break were measured. The belt-shaped sample (8× 1 cm) of the film was stretched by the instrument at a velocity of 1 mm/s. The color and transparency of the samples were evaluated in the black box by image processing technique. Total color difference (ΔE), yellow index (YI), and white index (WI) of the samples were calculated. Treatments were prepared according to central composite design (CCD) and were statically analyzed by response surface method (RSM). 

    Results and Discussion

    The prepared films showed low water vapor permeability (3.62× 10-11 to 2.23× 10-12 gm/m2Pas). The lowest amount of water vapor permeability was obtained when the low level of nanocrystalline cellulose (4.4%) was used. The high amounts of glycerol and nanocellulose increased the solubility of the films and even in some treatments the samples were completely dissolved in water. The hydrophilic nature of the gelatin and carboxymethyl cellulose used in the preparation of composites may be the reason for the high solubility of the produced films. At the same time, the samples showed high moisture absorption. Moisture absorption decreased as a result of the glycerol content increased, also the effects of the presence of nanocrystalline cellulose as a filler on the moisture absorption decrease cannot be neglected. A moderate contact angle of about 60º was observed, the interactions between the polar and the hydroxyl groups of the biomaterials used in the production of composites caused different behaviors observed in the various treatments. The interaction of nanocellulose and glycerol had a significant effect on the contact angle. The films had high ultimate tensile strength (84.37 MPa) while the elongation at break was 4.14% for the same treatment, which indicates low flexibility of the produced films. The color of the samples was evaluated as suitable. The use of 60% glycerol and 4.4% nanocellulose results in the production of films with desirable properties. The use of gelatin and carboxymethylcellulose produced composites that had improved properties in the terms of water vapor permeability and surface wetting compared to pure films.Composites made of gelatin and carboxymethylcellulose showed high ultimate tensile strength, although the elongation at break of them was not desirable. In terms of barrier properties against the water vapor, prepared composites demonstrated improved properties when compared to other bio-based made films. On the other hand, in terms of hydrophilicity, they are classified as moisture-sensitive films, which limits their use for foods with high moisture content. The use of carboxymethyl cellulose can improve the water vapor permeability of pure gelatin films. Also, the use of gelatin increases the contact angle of water of pure carboxymethyl cellulose films. Gelatin-carboxymethyl cellulose nanocomposite contains 60% glycerol and 4.4% nanocellulose presents improved and desirable properties.

    Keywords: Gelatin, Carboxymethyl Cellulose, nanocellulose, hudrophilicity, Mechanical properties
  • Mostafa Rahmati-Joneidabad *, Behrooz Alizadeh Behbahani, Mohammad Noshad Pages 699-709
    Introduction

    Economic losses can occur due to the growth of fungi on foods that lead to food spoilage and plant diseases. Fruits and vegetables are often exposed to microbial activity, caused by pathogenic fungi, during post-harvest storage. Diseases of food origin are a growing public health problem. Thus, food safety has become a major public concern as microbial contamination increases the risk of foodborne illnesses and shortens the shelf life of foods. Infection with fungi such as Aspergillus, Rhizopus, and Penicillium species is considered as the primary cause of rapid spoilage of fresh produce, which reduces their quality and shelf life. Synthetic fungicides have been applied to solve this problem for many years. Nonetheless, the adverse effects of synthetic chemicals on human health and the emergence of fungicide-resistant strains have motivated the scientists and food industries to find out safe preservatives to control postharvest rot/diseases. On this point, natural antimicrobial agents such as plant extracts and essential oils are gaining more and more interest. In this study, we used Levisticum officinale Koch essential oil, which its antimicrobial and antioxidant activity has been reported in literatures. 

    Materials and Methods

    L. officinale Koch essential oil was obtained by hydrodistillation method and its total phenol content, total flavonoids, antioxidant activity (based on DPPH and ABTS free radical scavenging and β-carotene bleaching tests) and its antifungal effect against fungi causing apple and orange rotting (Alternaria alternata, Penicillium expansum, Penicillium digitatum, Penicillium italicum, and Botrytis cinerea) were examined according to antimicrobial tests of disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration. 

    Results and Discussion

    L. officinale Koch essential oil contained 61.27 ± 0.34 mg GAE/g and 20.14 ± 0.21 mg QE/g total phenol and flavonoids, respectively. Its antioxidant activity, based on DPPH free radical scavenging, ABTS free radical scavenging, and β-carotene bleaching inhibition were 69.72 ± 0.65%, 78.54 ± 0.3% and 57.50 ± 0.41%, respectively. L. officinale Koch essential oil was effective against all fungal species and the highest susceptibility was observed for Penicillium expansum. According to the results, L. officinale Koch essential oil can be used as a natural antifungal agent to prevent post-harvest diseases of fruits and vegetables.

    Keywords: Levisticum officinale Koch, Essential oil, Antioxidant effect, antifungal effect, Natural preservative
  • Arman Naderi, Soheila Zarringhalami * Pages 711-723
    Introduction

    Bread is an important staple food widely consumed all over the world including Iran. The consumption of traditional breads in Iran, including Barbari, Sangak, Taftoon and Lavash, is steadily increasing because of its convenience and being a ready-to-eat food product normally consumed at breakfast, lunch and dinner. Hence, fortification of several types of bread with other cereals, pseudo cereals, legumes and oil seeds flours, has received considerable attention. Sesame, although referred to as “seed of immortality” and “queen of oilseeds” is considered as a rich food as it has a high nutritive quality. Apart from being a prominent oilseed (45-50%), sesame seeds are a rich source of protein (18–40%). Also, sesame was reported as a rich source of vitamins and minerals. Therefore, in the current study, the effect of wheat flour fortification with sesame flour at the ratio of 0, 5, 10 and 15 % on flour, dough, Sangak and Barbari samples properties was evaluated. 

    Material and Methods

    Proximate analysis of flour samples (sesame, wheat and composite flour samples) including acid value, moisture, ash, protein and wet gluten contents of the flour samples were determined according to the AACC methods. Water absorption, dough development time, dough stability time, degree of softening and the ratio between resistance to extension and extensibility (R/E), of prepared dough samples were determined according to AACC 21-54 and AACC 10-54 standard methods. After 2 h of bread baking the crust color parameters (L*, a* and b*) were determined using the Hunter–Lab Color flex Colorimeter (Hunter Associated Lab, Inc., Reston, VA, USA). Crumb Hardness was also measured 2 h after baking using a texture analyzer (Texture Analyzer, Brookfield, CT3, USA). The organoleptic characteristics (taste, aroma, color, texture and overall acceptability) of the prepared bread samples were evaluated by 15 trained panelists familiar with the traditional bread usually consumed, using 5-point hedonic scale (5 = like extremely, 1 =dislike extremely) test. The data was analyzed by one way analysis of variance (ANOVA). A multiple comparison procedure was performed by Duncan’s new multiple range test using SPSS Software. Significance of the difference was defined as p <0.05. 

    Results and Discussion

    According to the results obtained from flour samples analysis, sesame flour contained higher amounts of protein, lipid and ash and low amount of moisture and gluten than wheat flour. Furthermore, with increasing the amount of sesame flour, ash and protein contents of flour samples were increased, but their moisture and gluten contents were decreased. Furthermore, Farinograph parameters including water absorption and stability were decreased, but dough development time and degree of softening were increased with increasing the amount of sesame flour in the formulation. The results of Extensograph test also, showed the R/E ratio, which indicates dough stability during fermentation, was decreased when the sesame flour content increased. Therefore, the addition of sesame flour induced to weaken the gluten network formation in dough samples. The qualitative characteristics results of bread samples showed that addition of sesame flour to bread formulation tends to decrease crumb hardness and had no effect on color attributes (L*, a* and b*). Sensory evaluation results showed the higher total acceptability of Sangak and Barbari bread samples containing 10 and 5 % of sesame flour, respectively. In these ratios the color and texture of bread samples were also similar to related control bread samples. According to the results obtained in the current study and based on the functional properties of sesame flour (rich source of oil, protein, minerals, vitamins and antioxidant compounds) that reported by several previous studies, addition of 5 and 10 % of sesame flour in large scale production of Barbari and Sangak breads is recommended. Due to the high consumption of Sangak and Barbari breads in Iran, fortification of these breads can be effective in providing the daily needs of several nutrients.

    Keywords: Barbari, Fortification, Sangak, Sesame flour, Wheat flour
  • Shahab Naghdi, Masoud Rezaei *, Mehdi Abdollahi, Mehdi Tabarsa Pages 725-738
    Introduction

    Bioactive compounds are substances found in small amounts in food. In addition to their influence on human development, these compounds also play a crucial role in reducing diseases in human. Polysaccharides are a group of bioactive compounds that come from a variety of sources. Polysaccharides are macromolecules that are usually composed of more than ten monosaccharides. The constituent monosaccharides are arranged linearly or branched together through glycoside bonds, depending on the length of the chain and the number of constituent monosaccharides. They also have different molecular weight. Polysaccharides, like other essential macromolecules such as proteins and poly-nucleotides in the body, are essential for the flaxseed body's daily activities and play an influential role in cell-cell communication, cell adhesion, and the identification of molecules in the immune system. A group of polysaccharides derived from marine sources are sulfated polysaccharides. These polysaccharides are a broad branch of the resulting polysaccharides. In industrial quantities, sulfated polysaccharides are produced from pig skin and pig bone, and there are some restrictions on the use of these products in some countries. The limitations on the use of these products made from pig waste are the risks of transmitting influenza, as well as the prohibition of pork in some Islāmic countries. In this regard, by-products from seafood processing, which account for about 20 to 50 percent of the initial weight of raw material, are one of the sources that researchers are considering to extract these compounds. 

    Material and Method

    After preparation of the by-product, it was covered with ice in a ratio of 1 to 3 and transferred to the laboratory of Tarbiat Modares University. The sample was then washed and then ground. Finally, it was packed in plastic bags and kept in the freezer at -18 ° C until the day of experiment. Then, the enzymatic hydrolysis method and precipitation by ethanol were used to get sulfated polysaccharides. Chemical analyses were performed to determine carbohydrates, sulfates, proteins, and uronic acid content. The FTIR spectrum of extracted sulfate polysaccharide was determined using an FTIR spectrophotometer in the range of 400-4000 cm-1. Evaluation of antioxidant properties of obtained sulfate polysaccharide was assessed by DPPH free radical scavenging activity, ABTS free radical scavenging activity, and ferrozine tests. Emulsifying and foaming properties were also evaluated as functional properties. 

    Results and Discussion

    In the present study, sulfated polysaccharide was extracted from Rainbow trout (Oncorhynchus mykiss) skin by pepsin enzyme and its FTIR spectrum, carbohydrate, sulfate, uronic acid and protein were analyzed. The results of the chemical analysis of the extracted polysaccharide showed that the extraction efficiency was 3.23± 0.02%, as well as the percentage of carbohydrate and protein of the obtained polysaccharide was 57.03± 2 2.56, 7.78± 0.43% respectively. Also, the amount of sulfate and uronic acid were 6.54± 0.77 and 3.86± 0.43, respectively. The results of infrared spectroscopy showed the presence of a broad peak in the range between 3350 and 3450 cm-1 for the –OH group and the S=O sulfate flexural band in the range of 1245 cm-1. An increasing and significant trend was observed in different concentrations used for the DPPH test (p <0.05) which had the highest neutralizing power (38.85%) at a concentration of 2 mg/ml. The highest percentage of ABTS radical chelating was observed at a concentration of 4 mg/mm of distilled water with 71.70% (p <0.05). The chelating results of the extracted polysaccharide against ferrous ions showed that the highest chelating percentage was 98.43% (p <0.05). The foaming capacity, stability properties of the foam, and the emulsifying ability of the studied sample showed a trend of increasing the concentration coefficient of the sample (p <0.05), and the concentration of 10% used sulfated polysaccharide had the highest foaming percentage (72/22%) and foam stability (62.22%) (p <0.05). The emulsifying property of extracted sulfate polysaccharide against soybean oil was higher in all concentrations used than sunflower oil (p <0.05), and the highest value of that was related to the concentration of 10% with 86.57% and 92.59% against sunflower oil and soybean oil (p <0.05). The obtained results demonstrated that the fish skin extracted polysaccharide can serve as a natural antioxidant and functional agent in the food industry

    Keywords: Rainbow trout (Oncorhynchus mykiss), Sulfated polysaccharide, antioxidant properties, Foaming properties, Emulsifying properties
  • Marjan Zargar, Bahareh Shabanpour *, Parastou Pourashouri, Ebrahim Zabihi Neyshbouri Pages 740-749
    Introduction

    Collagen is the most abundant and important structural protein in the connective tissue of animals, the production of which is of great importance in the fields of medicine, cosmetics and food. Due to religious restrictions as well as common diseases between livestock and humans, today collagen extraction has turned to other sources, especially aquatic sources. Therefore, the aim of this study was to extract collagen by conventional acidic and enzymatic methods from common carp scales and determine its characteristics in order to make optimal use of this waste to produce valuable products and find alternatives to collagen obtained from land animals. 

    Material and Method

    Acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) were extracted from common carp scales (Cyprinus carpio) and their properties were determined. Common carp scales were prepared with the use of 0.5 M acetic acid and pepsin enzyme. Finally, the extracted collagens were lyophilized and after calculating the extraction efficiencies, their characteristics were determined by electrophoresis tests, UV spectroscopy, X-ray diffraction and isoelectric point determination.  

    Results and Discussion

    The results showed that the extraction efficiencies of ASC and PSC were 1.9% and 2.96% (based on dry weight), respectively, which means digestion with pepsin could increase collagen efficiency up to 1.54 times. The results of SDS-PAGE analysis showed that both ASC and PSC are type I collagen and are composed of α1, α2 and β in the (α1) 2α2 chain structure; the isoelectric point of collagens was in the pH range of 5-6. The maximum absorption peak of the UV spectrum of collagen was observed at 235 nm. Although pepsin enzyme (1% dry weight of scales) increases efficiency without significant changes in collagen native structure, but its use for mass production of type I collagen in Iran is not recommended unless self-sufficiency and reduction of pepsin price achieved, while collagen extraction by acidic method is very simple and research to design a production line for this method is recommended. Common carp scales have the potential to be used as an alternative source of collagen in the food and health-pharmaceutical industries. These results can provide a solution to control the waste of the aquatic processing industry in creating environmental pollution, as well as producing a high value-added product from common carp scales.

    Keywords: Scales, Common carp (Cyprinus carpio), Acid-soluble collagen, Pepsin-soluble collagen, waste
  • Zahra Sadri Saeen, Mohammadreza Khani *, Vajihe Fadaei Noghani Pages 751-763
    Introduction

    Butter is a type of dairy product made of sweet cream or sour cream. It is a perishable food that can be spoiled due to chemical changes during storage. Rancidity is one of the main problems caused by lipolysis and oxidation of fatty acids, which cause off-flavor and reduce the nutritional quality of butter. By adding low concentrations of antioxidant compounds, autooxidation can be prevented or delayed. It is also possible to increase the shelf life of butter by adding antioxidants. However, the carcinogenic effect of some synthetic antioxidants and consumer preference has led manufacturers to use more natural antioxidants. Chia seeds contain significant amounts of protein, fat, carbohydrates, minerals, and vitamins. Moreover, many bioactive compounds with high antioxidant potential are found in chia seeds such as phenolic acids, flavonoids, tocopherols, and sterols. Therefore, the present study was conducted to investigate the effects of chia seed extract in sweet cream butter to improve its chemical and sensory properties during refrigeration storage. 

    Materials and Methods

    For this purpose, the alcoholic extract of chia seed was prepared by adding chia seed powder to 70% ethanol (5% w/v) with stirring for 24 h, at room temperature. The filtered extracts were concentrated with a rotary evaporator. The concentrated mixture was dried in an oven at 40 °C and kept in an amber glass container in the refrigerator at 4 °C until the experiment was performed. Total phenolics content and antioxidant activity of chia seed extract were evaluated by the Folin–Ciocalteu colorimetric method using gallic acid as standard and for free radical scavenging ability by DPPH (2,2-diphenyl-1-picryl-hydrazyl) method, respectively. Then, chia seed extract was added to butter with different percentages (0.05, 0.1, 0.25, and 0.5%) and its effects on chemical properties including acidity, acid value, peroxide value, and thiobarbituric acid were evaluated for two months at 15-day intervals in refrigerated storage. Also, sensory properties including color, odor, taste, texture, and overall acceptance of butter samples were assessed using 15 untrained evaluators based on a 5-point hedonic test as above conditions. The results were reported as means± standard deviation and they were analyzed with analysis of variance using the software SPSS version 14. Statistical differences were analyzed by Duncan’s multiple range test (p<0.05). 

    Results and Discussion

    The results of total polyphenols content were 1108.78 ± 111.79 mg gallic acid per 100 g of extract and radical scavenging activity of chia seed extract in the concentration range of 4 to 20% was 35.17 ± 0.47 to 64.92 ± 2.95%. Also, the efficient concentration (EC50) of chia seed extract was 12.13 ± 0.59 mg/L in this study. It is known that the smaller the EC50, it will be the greater the antioxidant or free radical scavenging activity. According to the results, it was found that the concentration of chia extract has a significant effect on free radical scavenging (p<0.05) so that with increasing the concentration of the extract, its inhibitory properties increased. The results showed that the addition of different concentrations of chia seed extract and storage time were significant on the acidity and acid value of butter samples so that with increasing the amount of chia seed extract in treatments, the amounts of acidity and acid value increased significantly (p<0.05). Also, the acidity and acid value in all samples of butter increased significantly with increasing storage time during refrigeration (p<0.05). However, the amount of these two indices in treatments containing chia extract increased at a slower rate than the control sample during storage time, which could be due to the effect of phenolic compounds in chia seed extract in controlling the activity of lipolytic enzymes. Moreover, the results revealed that with increasing the concentration of the chia seed extract from the 15th day to the end of the storage period, the amounts of peroxide value and thiobarbituric acid of butter treatments significantly decreased compared to the control sample (p<0.05). This is due to the antioxidant effects of phenolic compounds in chia seed extract that delay the oxidation process. In this study, all chemical indices increased significantly during the storage time (p<0.05). All the samples in evaluated sensory properties were significantly different from the control sample (except odor) during 60 days of storage (p<0.05), in this way treatments had better sensory scores in color and taste properties compared to the control. In general, a concentration of 0.5% chia extract delayed oxidative damage, but in terms of sensory evaluation, a treatment containing 0.25% chia extract is selected and introduced as the most desirable treatment.

    Keywords: Chia seed extract, Butter, Antioxidant activity, Chemical properties, Sensory Properties
  • Hamed Saberian *, Vahid Pasban Pages 765-777
    Introduction

    Anthocyanins are one of the most important of food colorants, which are found in many fruits, flowers, and vegetables, and have been used as natural pigments in commercial foods and beverage products due to their desirable colors and potential nutritional benefits. Saffron (Crocus sativus) is the most expensive spice of the world and an average 86.4% of wet weight or 96.4% of dry weight of saffron flowers is related to petals. Saffron petals usually do not have a commercial value but contain large amounts of anthocyanins, flavonoids and glycosides. Thus, these petals can be a good source of natural dyes applicable in pharmaceuticals, confectionery, and soft drinks. However, anthocyanins are readily unstable compounds with exposure to oxygen, pH, temperature, enzyme, light, as well as surrounding components, which reduces food color and quality. Losses of anthocyanins occur during juice processing and storage, and methods are needed to prevent these losses. Up to now, various methods including the encapsulation and the co-pigmentation have been tried to intensify the stability of anthocyanins. The co-pigmentation based on the molecular interactions, has been shown to be an efficient way to stabilize anthocyanins. The addition of organic acids, flavonoids, alkaloids, polysaccharides, proteins, etc. as a co-pigment, can improve the stability, and change the bioactivity of anthocyanins. Encapsulation of anthocyanins by alpha and beta cyclodextrins is a potential treatment that could d anthocyanin losses. Anthocyanins can form inclusion complexes with cyclodextrin molecules, which may protect anthocyanins from hydration and polymerization reactions. Therefore, saffron petal is a potential resource of anthocyanin in Iran. Low thermal stability of the anthocyanins caused a tendency to the synthetic colorants. Therefore, the main goal of this research was to investigate the effect of cyclodextrins and co-pigmentation on the anthocyanin extract of saffron petal during heat treatment. 

    Materials and Methods

    Anthocyanin extract of saffron petal was extracted by 50% acidic ethanol solution at ambient temperature. Acidified extract was concentrated by a rotary evaporator at 40˚C up to 9 percent concentration of solid materials. Different concentrations of alpha and beta cyclodextrin (10, 25, 50, 75 and 100 mole alpha or beta cyclodextrin to one mole anthocyanin) and also, different co-pigments such as gallic acid (at two molar ratio of 50:1 and 100:1of galic acid/anthocyanin), ferulic acid (at two molar ratio of 50:1 and 100:1of ferulic acid/anthocyanin), quercetin (at two molar ratio of 2.5:1 and 5:1 of quercetin/anthocyanin) and rutin (at two molar ratio of 10:1 and 25:1 of rutin/anthocyanin) were used to study the thermal stability of anthocyanin. Furthermore, the hydroalcoholic extract of rosehip was prepared and concentrated thereby, the rosehip extract (at two molar ratio of 50:1 and 100:1gallic acid equivalent/anthocyanin) was used as a co-pigment. Total anthocyanin content was measured using differential pH method and reported based on mg of cyanidin 3-glucoside per 100 ml the model drink. a* value was measured by Hunter Lab. Model drink (20 mM acid citric buffer in pH of 3) containing 0.01 % CaCl2 and anthocyanin extract was prepared. Prepared model drinks were heated at 90 °C during 0, 15, 30, 45, 60, 90 and 120 min and then, were cooled up to room temperature. Half time of anthocyanin was calculated and the mentioned treatments were investigated to evaluate the stability of the different compounds. 

    Results and Discussion

    The results indicated that alpha cyclodextrin at molar ratio of 50:1 (alpha cyclodextrin to anthocyanin) hadn’t any significant effect on the anthocyanin stability but beta cyclodextrin at molar ratio of 50:1 increased the colorant stability, which can be due to the smaller cavity of alpha cyclodextrin rather than beta cyclodextrin that lead to the lower interaction between alpha cyclodextrin and anthocyanin. Although, phenolic co-pigments hadn’t any significant effect on the anthocyanin stability of the model drink but the rosehip extract at two molar ratios of 50:1 and 100: 1 increased the anthocyanin retention. Total phenolic content of rosehip extract was 14.56 g gallic acid equivalent per liter of the extract and total flavonoid content was 365 mg quercetin equivalent per liter of the extract. According to the studies and our results about total phenol and flavonoid content, the increased retention of the anthocyanin can be related to the variety of the phenolic and flavonoid compounds of the rosehip extract. Therefore, beta cyclodextrin as a trapping agent and rosehip extract as a co-pigment, can increase the anthocyanin stability of the saffron petal during heat treatment.

    Keywords: Thermal Stabilization, Anthocyanin, saffron petal, β-cyclodextrin, Rosehip extract