Effect of Kefiran and Milk Proteins Addition on the Rheological Behavior of Glucono-delta-Lactone Induced Milk Gels

摘要

The properties of kefiran as a texture modifier was evaluated providing new perspectives in understanding the rheology of fermented dairy products and the possibility of using this generally recognized as safe polysaccharide as an additive in dairy and other foods. For this purpose, the effect of kefiran, Sodium Caseinates (SCN) and Whey Proteins Concentrates (WPC) addition on the rheological behavior of glucono-delta-lactone (GDL) induced milk gels was evaluated. The acidified milk samples were prepared from homogenized and pasteurized full fat (3.5%) bovine milk with or without the addition of kefiran, SCN and WPC at 1.5% concentration. The incubation temperature was set at 37°C. According to the results, the incubation time required for the pH to reach 4.4 increased with increasing SCN and WPC concentration. Kefiran addition did not affect incubation time, however it did enhanced elasticity, apparent viscosity and thixotropic behavior of milk gels. The impact effect of kefiran on the rheological behavior of acid milk gels was more pronounced when compared to that of WPC, but lower to SCN effect. The protein matrix of GDL induced milk gels is governed by hydrophilic interactions in the presence of kefiran or WPC and by hydrophobic ones when SCN are added.