نوع مقاله : مقاله پژوهشی

نویسندگان

• رؤیا کاظمی زاده ¹
• وجیهه فدائی نوغانی ²

¹ دانشگاه آزاد اسلامی واحد ورامین-پیشوا

² دانشگاه آزاد اسلامی واحد شهر قدس

چکیده

پوست انار بخش غیرقابل خوردن حاصل از فرآیند آبگیری میوه انارو منبع غنی از تانن‌ها، فلاونوئید‌ها و ترکیبات فنولی دیگر می‌باشد. شهد خرما، نیز طعم و بوی منحصر به فردی دارد؛ و می‌تواند به‌عنوان شیرین‌کننده طبیعی کاربرد داشته باشد. امروزه، توجه مصرف‌کننده به سوی غذاهای سلامتی‌بخش معطوف شده است و ترکیبات فنلی موجود در انار و پوست آن می‌توانند چنین نقشی را ایفا کنند؛ علاوه‌برآن، دارای خواص ضدباکتریایی بالایی هستند. در این مطالعه، تأثیر افزودن عصاره آبی پوست انار در مقادیر 10، 20 و 30 درصد حجمی/ حجمی همراه با شهد خرما در مقادیر 2، 4 و 6 درصد حجمی/ حجمی بر خاصیت ضداکسیدانی، محتوای پلی‌فنل کل و شمار شکلی بار میکروبی شیر‌ طعم‌دار فراسودمند در طول 21 روزنگهداری در سرما موردبررسی قرار گرفت. برای تولید نمونه‌‌های شیرطعم‌دار، پیش‌گرم‌کردن شیر تا دمای 50 درجه سانتی‌گراد انجام پذیرفت؛ شهد خرما و عصاره پوست انار به شیر اضافه و به‌مدت 5 دقیقه مخلوط شدند؛ سپس، مخلوط در دمای 75 درجه سانتی‌گراد به‌مدت 15 دقیقه حرارت داده شد. نمونه‌های شیرطعم‌دار فراسودمند، پس از خنک شدن تا دمای 25 درجه سانتی‌گراد، در دمای 4 درجه سانتی‌گراد نگهداری شدند. بر اساس پژوهش حاضر، با افزودن عصاره پوست انار،فعالیت ضداکسیدانی و محتوای پلی‌فنل کل افزایش یافتند (p

کلیدواژه‌ها

• شیر طعم دار
• عصاره پوست انار
• شهد خرما
• خاصیت آنتی‌اکسیدانی
• شمارش کلی بار میکروبی

عنوان مقاله [English]

The determination of antioxidant activity, total polyphenols and microbial total count of functional flavored milk containing pomegranate peel extract and date datesyrup during cold storage

نویسندگان [English]

• Roya Kazemizadeh ¹
• Vajiheh Fadaei Noghani ²

¹ Varamin - Pishva Branch, Islamic Azad University

²

چکیده [English]

Introduction: Flavored milk is a healthy beverage, nutritious, delicious and thirst elimination by a large group of people, especially children consumed. Therefore, the need to find different ways to enhance the nutritional value of milk and its products is of many researchrs’ interest.Pomegranate fruits peel is an inedible part obtained during processing of pomegranate juice. Pomegranate peel is a rich source of tannins, flavonoids and other phenolic compounds;which is currentlybeingwidely used in medicine and food industry. Moreover, consumers prefer to use natural antioxidants rather than synthetic ones. The datedatesyrup has unique odor and taste; it has high potential to be a new sweetener which is natural and chemical-free. Datesyrup hasa natural sweetness and is considered easy to digest. Also, it has low fat, no cholesterol and saturated fat and a good source of dietary fiber is considered. In this study, the effect ofaqueous extract of pomegranate peel adding at levels 10%, 20%, 30% and datedatesyrup adding at levels 2%, 4% and 6% on antioxidant property, total polyphenols contents andmicrobial total countof functional flavored milk was investigated during 21-day cold storage.
Materials and method: Raw milk from Deniz factory (Iran), date syrup with Brix ° 83 from Dombaz company (Iran), Reagent Folin - Ciocalteau, reagent 2,2-Di Phenyl-1-Picryl Hydrazyl(DPPH) and gallic acid mono-hydrated from Sigma (America) were prepared. Other laboratory chemicals and PC-AGARCulture media from Merck (Germany) was purchased.Also, pomegranate variety of Shiraz Black Tail (Iran) was used.
Preparation ofAqueous extract of pomegranate peel
Fresh pomegranate was washed and peeled and stored at room temperature away from sunlight for a week. 50gr of powdered pomegranate peelwas mixed with 500 ml of distilled water with temperature of 30°Cand was maintained at 30°C for 12 hours.
Preparation of flavored milk
The milk used for producing functional flavored milk samples was preheated at 50ºC, then date syrup was addedat levels of 2%, 4% and 6% and aqueous extract of pomegranate peel was also added at levels of 10%, 20% and 30% to milk and the whole mixture was mixed for 5 minutes; The mixture was then heated to75ºCfor 15 minutes. After cooling at 25°C, flavored milksamples were refrigeratedat 4ºC.
Determination of antioxidant activity
The antioxidant activityof flavored milk samples was measured according to Elfalleh et al. (2012) method using model CARY 50spectrophotometer,Australia, at 517 nm by a Radical Scavenging Activity (RSA) and DPPH reagent .
Determination of total polyphenols
The total polyphenolsof flavored milk samples were measured according to Elfalleh et al. (2012) method usingmodel CARY 50spectrophotometer,Australia, at 765 nm by Folin- Ciocalteu reagent. The amount of phenol content was calculated by standard curve of gallic acid .
Microbial total count
Microbialtotal count was determinedin plate count agar according to Iranian National Standard no.5484. Sample plates were incubated in model zn1434incubator, Iran, at 31 ° C for 72 hours.
Experimental design
In this study, A completely randomized design was employed usng SAS software (version 9.1) to determinate the antioxidant activity, total polyphenols and microbial count. The experiment was consisted of three factors including pomegranate peel extract (in three levels 10, 20 and 30%), date syrup factor (in three levels 2, 4 and 6%) and time (in four days 0, 7, 14 and 21).
Results and Discussion: According to present research, with adding pomegranate peel extract percentage of free radical scavenging and total polyphenols content increased (p

کلیدواژه‌ها [English]

• Flavored milk
• Pomegranate peel extract
• Palm syrup
• Antioxidant activity
• microbial total count