Crosslinking of milk whey proteins by transglutaminase

Milk whey powder was used to evaluate the polymerization reaction of the proteins α-lactalbumin and β-lactoglobulin by the enzyme transglutaminase. Measurement of the flow behavior was carried out as a parameter to monitor the viscosity changes of the solutions after the enzymatic reaction. Through an experimental design the optimum reaction conditions were evaluated as a function of the enzyme concentration, temperature and reaction time. The protein polymerization was favored when the solutions were kept at a temperature of 36 °C for 4 h. The formation of polymers increased proportionally with an increase in transglutaminase up to a maximum point of substrate exhaustion, reaching an ideal enzymatic concentration of 50 U of transglutaminase/g of protein. An increase in the content of high molecular weight polymers in the milk whey solutions resulted in an increase in the consistency index of the solutions, favoring non-Newtonian behavior.