عنوان :
اثر ميزان پروتئين هاي آب پنير، نمك و PH بر پايداري كلوئيدي دوغ
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
علوم و صنايع غذايي
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي
صفحه شمار :
پانزده، 115ص.: مصور، جدول، نمودار
يادداشت :
ص.ع. به فارسي و انگليسي
استاد راهنما :
علي نصيرپور
استاد مشاور :
محمود شيخ زين الدين، جواد كرامت
توصيفگر ها :
ميزان دوفاز شدن , رسوب , ويسكوزيته , طرح RSM
تاريخ نمايه سازي :
21/5/91
استاد داور :
ناصر همدمي، محمد خوروش
تاريخ ورود اطلاعات :
1396/09/18
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Abstract Doogh an acidified milk drink made from yoghurt water and salt is a favorite refreshingbeverage in Iran and some parts of Middle East Phase separation of Doogh during shelf life however is believed to be the main obstacle in the way of its overall consumption The problem is likely causedby large colloidal particles of doogh low pH and the aggregation of casein Considering the highpolluting power of whey and the existing problems for its disposal as well as its high nutritional value has made it essential to carry out a wide research on use of product in formulations and compoundsdifferent foods is done In recent years many attempts have been put in order to produce whey proteinconcentrate So far little research has been done on the stability of acidified milk drinks with wheyproteins On the other hand pH and ionic strength of environment are the two effective factors in thestability of such products The purpose of this study was to investigate the effects of whey proteins pH and dissolved saltin milk on the colloidal stability of Doogh In order to fulfill these requirements five concentrationsof whey protein from 0 5 to 4 0 three pH levels 3 5 4 and 4 5 and five concentrations 0 0 5 1 1 33 and 2 of dissolved salt in the milk were used The influence of the foregoing factors onthe amount of phase separation sedimentation and the product viscosity using the RSM design andduring 28 days storage of product at 5 C were studied Furthermore the micro structure zeta potential particle size distribution and sensory characteristics of the samples were investigated It was foundthat appropriate models to determine the amount of phase separation and sedimentation werequadratic models and 2FI for determining the viscosity It was observed that with increasing amountof whey protein and salt in milk phase separation reduced While increasing whey protein anddecreasing pH decreased amount of sedimentation Increasing pH and salt concentration in milk andwhey proteins increased samples viscosity In addition increasing the amount of whey protein inDoogh reducing pH of product and the amount of salt dissolved in the milk reduced the size of thecolloidal particles of Doogh All of Doogh samples showed Newtonian behavior but in samples withpH 4 5 and 4 whey proteins and 2 salt dissolved in milk was observed pseudo plastic behavior Samples with lowest phase separation had higher zeta potential value and zeta potential of sampleswith pH 3 5 and 4 5 were positive and negative respectively The results of Experiments duringstorage of the product showed increasing the amount of whey proteins and salt not only reducedamount of phase separation of product during the storage but also the rate wass reduced In all thesamples viscosity of product during storage was constant but in samples with pH 4 5 4 wheyproteins and 2 dissolved salt in milk viscosity decreases during storage Investigating sensoryproperties of product showed the sample containing 0 5 whey protein in terms of flavor and overallacceptability of product compared with the sample containing 4 whey protein has been moreacceptability Key Words Doogh Whey Proteins pH Salt Colloidal Stability Phase Separation Sedimentation Viscosity RSM Design
استاد راهنما :
علي نصيرپور
استاد مشاور :
محمود شيخ زين الدين، جواد كرامت
استاد داور :
ناصر همدمي، محمد خوروش
