The Effect of Emulsifying Salts on Physicochemical Properties and Enzymatic Gelation Time of Skim Milk

Subject Areas : Microbiology

Mahdokht Ehteshami ¹ , Hamid Ezzatpanah ² , Soleyman Abbasi ³ , Mohammad Hadi Givianrad ⁴

1 - دانشجوی کارشناسی ارشد دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، ایران
2 - دانشیار گروه تخصصی علوم و صنایع غذایی، دانشکده کشاورزی و منابع طبیعی، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، ایران
3 - دانشیار آزمایشگاه کلوئیدهای غذایی و رئولوژی، دانشگاه تربیت مدرس، دانشکده کشاورزی، گروه علوم و صنایع غذایی، تهران، ایران
4 - استادیار دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، گروه شیمی تجزیه، ایران

Received: 2012-12-10 Accepted : 2013-05-11 Published : 2013-09-23

Keywords: Enzyme Induced Casein Gel, Gelation Time, Tetrasodium Pyrophosphate, Trisodium Citrate,

Abstract :

Introduction: Milk proteins are able to form gel under different situations such as heating, acidification, adding the enzymes and emulsifying salts. In this study, the effect of adding tetrasodium pyrophosphate (TSPP) and trisodium citrate (TSC) on physicochemical properties and rennet gelation time of unheated and heated skim milk was investigated. Materials and Methods: 2 to 10 mM TSPP and TSC were added to unheated and heated reconstituted skim milk. The pH, electro-conductivity (EC), and turbidity of samples were measured and upon the rennet treatment, the gelation time and water holding capacity (WHC) of treated samples were determined.Results: Based on our findings, addition of TSPP and TSC increased the pH and EC while it decreased the turbidity of the samples. Moreover, the presence of these salts extended the rennet gelation time of induced casein gels and gelation was only observed in the samples containing 2 and 4 mM TSC, and 4, 6, and 8 mM TSPP. The WHC of the samples was increased as well.Conclusion: TSPP and TSC resulted in dispersing the casein and forming a new gel networks, that can contribute to the improvement of some properties of milk products.

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