Transglutaminase treatment to improve physical properties of acid gels from enriched goat milk

A combined treatment of dry matter enrichment and protein cross-linking with microbial transglutaminase was applied to improve the rheological and physical properties of acid gels from goat milk, which usually appear as weak because of a low S-casein content. Enzyme incubation was applied for 30–420 min and inactivation was achieved by heat treatment or by addition of N-ethylmaleimide. Subsequent acidification of enriched and cross-linked goat milk induced by d-glucono- -lactone at 30 ◦C, resulted in a significantly higher stiffness and lower syneresis of the gels compared to gels from untreated goat milk. Highest stiffness values were obtained after 300 min enzyme treatment, and an additional impact of the heating step for enzyme inactivation was observed. This combined procedure of dry matter enrichment and enzyme treatment allowed the production of gels with similar properties as gels from cow milk and appears as a promising tool to manufacture goat milk yogurt with satisfying texture properties.