Incorporation of microbial transglutaminase into non-fat yogurt production

This study investigated the physical, chemical and sensory characteristics of non-fat yogurts treated with microbial transglutaminase (MTGase) at varying concentrations from 0 to 0.5 g L−1. Also, the effect of enzyme inactivation prior to fermentation on the selected properties of the yogurts was studied. Acid development rate was reduced with increasing MTGase doses. Cross-linking of milk proteins by MTGase had a growth-slowing effect on yogurt starter bacteria, which was more pronounced at higher concentrations. Physical properties of the yogurts were improved by MTGase throughout 21-day storage; on the contrary, the production of acetaldehyde was slowed down by increasing MTGase concentrations during the same period. Principal component analysis (PCA) and hierarchial cluster analysis (HCA) clearly differentiated the samples with added MTGase at lower (⩽0.3 g L−1) and higher (0.4–0.5 g L−1) concentrations regarding the physical and sensory properties. The physical and sensory properties of non-fat set yogurt could be improved by incorporating MTGase up to a level of 0.3 g L−1.