Effect of microbial transglutaminase on thermal stability of milk protein

Abstract

At present, Transglutaminase (abbreviated as TG, EC2.3.2.13) has been used in meat products, dairy products and baked goods in Japan and other countries. The stability of MP (Milk protein) colloid system is very important to the quality of dairy products. The effect of MTG (Microbial TG) on the thermal stability of MP was studied in this experiment. The change of HCT (Heat Coagulation Time) of MP emulsion before and after adding MTG was measured. The results show that the effect of MTG on MP leads to the decrease of its solubility in the region of pH < 4.0 or pH > 7.0, but it increases in the range near the isoelectric point of MP (pH 4.0 ~ 6.0). In the range of acidic pH value with low stability, the high calcium ion activity, low Zeta potential and micelle hydration make the milk have poor thermal stability and will solidify rapidly at 150℃. The hydrophobic interaction between MTG and MP changes the conformation of MP, which leads to the change of thermal stability.