عنوان

بررسی ویژگی های فیزیکی- شیمیایی ، میکروبیولوژیکی و حسی ماست تغلیظ شده سنتی تولوق

‭۳۲۶پ‬

per

بررسی ویژگی های فیزیکی- شیمیایی ، میکروبیولوژیکی و حسی ماست تغلیظ شده سنتی تولوق

/کاظم علیرضا لو

: کشاورزی

‮‭۱۱۴‬ ص، جدول، نمودار، عکس، لوح فشرده‬

چاپی

واژه نامه بصورت زیرنویس

کتابنامه ص.: ‮‭۱۰۶-۱۱۴‬

کارشناسی ارشد

مهندسی کشاورزی-صنایع غذایی

‮‭۱۳۸۹/۱۱/۱۶‬

تبریز

ماست از پر مصرف ترین فرآورده های تخمیری شیر است که به دلیل ارزش تغذیه ای بالا و دارا بودن ترکیبات کاربردی - دارویی تاثیر بسیار خوبی روی سلامتی انسان دارد. اگرچه ماست دارای ویژگی های منحصر به فردی است ولی تمایل بالایی بویژه در دماهای محیط به فساد شیمیایی و میکروبی نشان می دهد که باعث بروز نقایص طعمی و بافتی ئر این محصول لبنی با ارزش می شود. همین موضوع به عنوان یک چالش مهم در صنعت شیر و فراورده های لبنی مطرح شده است، بنابراین ارائه راه کارهای ساده برای حفظ و افزایش کیفیت میکروبی و ماندگاری ماست از اهمیت ویژه ای برخوردار است

Yoghurt is the most consumed fermented milk product which has a great effect on human health because of its high nutritional value and functional pharmaceutical ingredients. Although yoghurt has unique characteristics, it shows high tendency to chemical and biological spoilage particularly in environmental temperatures which cause defects in taste and texture in this valuable dairy product. These problems have been suggested as a major challenge in the dairy industry and dairy products. Therefore, providing a suggestion to maintain and increase the microbial quality and shelf life of yoghurt is important. Using bags made of sheepskin and cloth is one of the most suitable and cheapest methods to concentrate yoghurt. Tuluq yoghurt is concentrated yoghurt which has been produced traditionally in skin bags from a long time ago in Azerbaijan regions, Iran. The aim of this research, which has been done for the first time in the world, was to study the physicochemical, microbiological, sensory properties and also the proteolysis profile of Tuluq yoghurt and introduce a traditional dairy product. Recent study also examined the variety of traditional methods used to produce, concentrated yoghurt in comparison with Tuluq yoghurt. In order to identify strengths and weaknesses of these different methods, a strategy to produce high quality and favorable Tuluq yoghurt should be presented. Results revealed that the treatment, storage and their interactions had significant effects (P < 0.05) on the physicochemical properties such as pH, acidity, total solid, fat, protein, salt, ash and lipolysis content. Results also showed that treatment had no significant effect (P > 0.05) on percentage of syneresis but storage and interaction of these factors had a significant effect (P < 0.05). In general, in all yoghurt samples, bacterial count such as streptococcus thermophilus, Lactobacillus bulgaricus were reduced during 60 days of storage. Wherese, counts of psychrotrophic bacteria, molds and yeasts increased. The level of coliform bacteria (less than 10 cfu/g), staphylococcus aureus (zero cfu/g) and Escherichia coli (zero cfu/g) remained constant. The use of the Tuluq bag in producing the concentrated yoghurt resulted in very low losses of nutritional compounds and essential minerals compared with cloth bags which are customary in most countries. Considering the high rate of desirable proteolysis and count of starter and non starter bacterial in Tuluq yoghurt it can be concluded that in the inner surface of the Tuluq bag were present some proteolytic bacterial and enzymes. Evaluation of the overall taste of yoghurt samples showed that the overall flavor score of Tuluq yoghurt at the end of 60 day storage period and the packaged yoghurt, after 30 days increased significantly (P < 0.05). While the overall flavor acceptability of control yoghurt decreased insignificantly during the 60 day storage period (P > 0.05), the cloth bag yoghurt tended to increase by insignificant differences (P > 0.05). Tuluq concentrated yoghurt had unique physicochemical and microbiological properties. Because of its proteolysis profile during storage, the appeal of its desirable sensory characteristics, and very low losses of nutritional compounds and essential minerals during

traditional concentrated yoghurt

tulug

physicochemical and microbiological properties

sensory

proteolysis

علیرضا لو، کاظم

حصاری، جواد، استاد راهنما

آزادمرد دمیرچی، صدیف، استاد راهنمای همکار

فرج نیا، صفر، استاد مشاور

قیاسی فر، شیوا، استاد مشاور همکار

سیاه و سفید

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