Physico-chemical properties of probiotic yoghurt produced with transglutaminase

The effect of different concentration of transglutaminase - TG (0.02%, 0.06% and 0.12%) on physico-chemical properties of probiotic yoghurt was investigated. Two series of yoghurt were manufactured on a laboratory scale from pasteurised skim milk (0.1 % w/w fat). Series I was produced with TGase activation during a period of 2 h at 40?C, while series II was produced without enzyme activation. Then, the adequate quantities of TGase and probiotic starter culture ABT-4 (Chr. Hansen A/S Denmark) were added. Chemical composition, physico-chemical properties (water holding capacity and whey separation) and sensory characteristics of yoghurt samples were determined after production and during 5 days of storage. Addition of TGase to milk (direct or after activation) for probiotic yoghurt manufacture improved its overall characteristics. Activation of TG in yoghurt production increases water holding capacity as well as decreases syneresis during the storage.