Effect of Sucrose on Proteolysis in Yogurt During Incubation and Storage

The influence of sucrose on proteolysis in yogurt during incubation and storage was investigated using five different commercial yogurt cultures. Proteolysis was monitored by liberation of alpha amino groups. Addition of 15% sucrose to milk inhibited proteolysis and acid production by the cultures during the last 2 h of incubation. Isometric illustrations of the combined effects of sucrose and storage time at 4°C on proteolysis showed that proteolysis was dependent on sucrose and storage time in each culture. However, the effects of sucrose and storage time on proteolysis differed with each culture. For some cultures, the combined effects of sucrose and storage time on proteolysis were dependent on the amount of milk fat in the milk. By determining the effect of processing variables on the degree of proteolysis in yogurt, it may be possible to predict the degree of proteolysis under defined conditions. These results may lead to strategies to minimize proteolysis and improve yogurt quality.