بررسی ویژگی‌های شیمیایی و میکروبی چند نمونه ماست محلی تهیه شده از فروشگاه‌های عرضه محصولات لبنی سنتی شهرستان تویسرکان

نویسنده
نوشین نوشیروانی
استادیار گروه علوم و صنایع غذایی، دانشکده فنی و منابع طبیعی تویسرکان، دانشگاه بوعلی سینا، همدان، ایران
10.22034/FSCT.21.156.63
چکیده
با توجه به تمایل بالای مصرف کنندگان به تهیه محصولات لبنی سنتی و تردید آنها به استفاده از محصولات کارخانه­ای این مطالعه با هدف بررسی ویژگی­های مختلف شیمیایی و میکروبی نمونه­های ماست سنتی عرضه شده در شهرستان تویسرکان و مقایسه آن با نمونه ماست پاستوریزه صورت پذیرفت. ویژگی­های شیمیایی شامل ماده خشک، رطوبت، اسیدیته، pH و چربی و ویژگی­های میکروبی شامل شمارش کلی میکروارگانیسم­ها، کلی­فرم، کپک و مخمر و استافیلوکوکوس اورئوس مورد بررسی قرار گرفته و با نمونه پاستوریزه به عنوان نمونه شاهد مقایسه شد. محتوای رطوبت و ماده خشک نمونه­ها به ترتیب از 33/84% تا 8/87% و 62/12 تا 25/15% متغیر بود. محتوای چربی ماست­های تولید شده بین 9/2-5/2 در محدوده ماست نیم چرب بر اساس استاندارد ملی ماست قرار داشت. بین نمونه­های مختلف از نظر رطوبت، ماده خشک و چربی تفاوت معنی داری مشاهده نشد ( 05/0 ˃ P). میزان اسیدیته (درصد وزنی بر حسب اسید لاکتیک) و pH نمونه­های مختلف به ترتیب بین 81/1 – 87/0 و 47/4 – 68/3 بود که کاملا با استاندارد ملی ماست (حداقل 7/0 می­باشد) مطابقت داشت. نمونه­های مختلف از نظر pH و اسیدیته تفاوت معنی داری را نشان دادند ( 05/0 ˂ P). نتایج ویژگی­های میکروبی بیانگر حضور کپک و مخمر در 100% ، کلی­فرم در 33/83% و استافیلوکوکوس اورئوس در 50% نمونه­ها بود. در خصوص ویژگی­های میکروبی تفاوت معنی داری بین نمونه­های سنتی و صنعتی مشاهده شد. به طوری که نمونه صنعتی کمترین بار میکروبی را نسبت به نمونه ­های ماست سنتی نشان داد ( 05/0 ˂ P). از این رو کنترل شیر خام ورودی و رعایت شرایط بهداشتی حین تولید، بسته بندی و عرضه در تولید محصولات سنتی اکیدا توصیه می­گردد. نتایج ارزیابی حسی رنگ و طعم و مزه بهتری برای نمونه پاستوریزه و بافت و پذیرش کلی بهتری را برای نمونه ­های سنتی نشان داد.


کلیدواژه‌ها
ماست
لبنیات سنتی
استاندارد ملی
ویژگی‌های شیمیایی
ویژگی‌های میکروبی

موضوعات

عنوان مقاله English

Investigating the chemical and microbial characteristics of some local yogurt samples prepared from traditional dairy products stores in Tuyserkan city

نویسنده English

nooshin noshirvani
Assistant Professor, Department of Food Science and Technology, Tuyserkan Faculty of Engineering & Natural Resources, Bu-Ali Sina University, Hamedan, Iran
چکیده English

Considering the great desire of concumers to consume traditional dairy products and their reluctance to use factory products, this study was conducted with the aim of investigating different chemical and microbial characteristics of traditional youghurt samples offered in Tuyserkan city and compare it with pasteurized yoghurt. The chamical characteristics inclusing percentage of dry matters, moisture content, acidity, pH and fat and microbial characteristisc including total bacterial count, coliforms, mold and yeasts, and Staphylococcus aureus were investigated and compared with the pasteurized sample as a control. The moisture and dry matter content of the samples varied from 87.7-84.33% and from 12.62 to 15.25%, respectively. The fat content of the yogurts produced was between 2.5-2.9 and thus within the range of semi-fat yogurts according to the national standard. No significant difference was observed between different samples in terms of moisture, dry matter and fat (P>0.05). The acidity (percentage by weight in terms of lactic acid) and pH value of various samples ranged from 0.87-1.81 and 3.68-47.4, respectively and were therefore fully in line with the national standard (at least 0.7). Different samples showed a significant difference in terms of pH and acidity (P < 0.05). The results of microbial characteristics indicate the presence of mold and yeast in all samples (100%), coliform in 83.33% and Staphylococcus aureus in 50% of the samples. Regarding microbial characteristics, a significant difference was observed between traditional and industrial samples. Thus, the industrial sample showed the lowest microbial load compared to the traditional yogurt samples (P < 0.05). Therefore, it is strongly recommended to control the incoming raw milk and observe the sanitary conditions during production, packaging and supply in the production of traditional products.

کلیدواژه‌ها English

Yogurt
traditional dairy
national standard
Chemical properties
Microbial properties
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