Insight into transglutaminase cross-linking induced gel strength and thermal stability improving of gelatin-based emulsion-filled gels

Generally, gelatin-based emulsion-filled gels (EFGs) tend to liquefy and degradation under heat sterilisation. In this study, transglutaminase (TG) cross-linking gelatin-based EFGs with high thermal stability and gel strength were prepared. By analysing the rheological properties, thermal stability, structural changes and their underlying mechanisms, the impact of varying cross-linking time on the thermal stability and gel strength of EFGs was explored. Results showed that enzymatic EFGs exhibited a higher gel strength with a high elastic modulus and low-frequency dependence along with a prolonged TG cross linking time. The thermal denaturation temperature was increased by 21.87 degrees C after TG cross-linking for 4 h compared to that of uncross-linked EFGs. The surface of fully cross-linked EFGs was smoother, and the surface voids were reduced. As the TG cross-linking time increased, the inter-molecular hydrogen bonds were weakened, the covalent bonds were strengthened and the triple helical structure was altered. After full cross-linking, the original ordered structure of gelatin molecules was destroyed, the formation of crystalline structure was hindered and the interplanar crystal spacing was more tightly. This study provides a facile method for the preparation of gelatin-based products with high thermal stability and proposes theoretical guidance for its practical application.

Automated summary

In this study, gelatin-based emulsion-filled gels (EFGs) with high thermal stability and gel strength were prepared by cross-linking with transglutaminase (TG). The impact of varying cross-linking time on the thermal stability and gel strength of EFGs was explored. The results showed that enzymatic cross-linking increased gel strength and thermal denaturation temperature, and affected the structural changes of EFGs.