Improved textural properties of transglutaminase treated milk acid gel: Influence of citric acid

Keeping the stability of yogurt during the fermentation, storage and transportation process is necessary to reduce the syneresis. To achieve this goal, the combination of the acid treatment and transglutaminase (TG) was proposed to improve the textural properties of milk acid gels. We investigated the synergistic effect of acid treatment and TG on the water holding capacity (WHC) and physical stability of milk acid gels. As the pH of the skimmed milk decreased from 6.7 to 5.2, the casein micelles dissociated into smaller particles, exposing more site for the crosslinking of TG. The WHC and stability of the TG-treated acid gels were significantly enhanced as the particle size of casein micelles decreased. Our results suggested that the combination of the treatment of acid and TG could significantly improve the textural properties of milk acid gels by the dissociation of casein micelles induced and increase in the covalent-crosslinking. This study provided a simple and novel method to improve the stability of the milk gels, which showed enormous potential for dairy processing.