Effects of tyndallization temperature on the sterility and quality of kamaboko

Mechanism study of the gel-forming ability of heat-induced gel from Peruvian hake (Merluccius gayi peruanus) surimi

The commercial value of Peruvian hake (Merluccius gayi peruanus) meat is low because of its soft texture. This study investigated the major factor contributing to the gel-forming ability of Peruvian hake surimi by comparing the effects of endogenous protease activity and parasitic infection. Heat-induced gels could not be obtained at 50 °C-90 °C. Surimi with severe parasitic infection showed a stronger gel-forming ability. The endogenous protease activities were the main factor influencing the Peruvian hake meat proteolysis and contributed to the low gel-forming ability, rather than parasitic infection. Specifically, endogenous cysteine proteases played an essential role in protein degradation and low gel-forming ability. Moreover, endogenous transglutaminase was also shown to be involved in the gel-forming ability upon heating at 40 °C. These results suggested that Peruvian hake meat could be used as a raw material of frozen surimi for fish gel by inhibiting the activity of endogenous proteases.

Molecular Dynamics-Assisted Design of High Temperature-Resistant Polyacrylamide/Poloxamer Interpenetrating Network Hydrogels

Polyacrylamide has promising applications in a wide variety of fields. However, conventional polyacrylamide is prone to hydrolysis and thermal degradation under high temperature conditions, resulting in a decrease in solution viscosity with increasing temperature, which limits its practical effect. Herein, combining molecular dynamics and practical experiments, we explored a facile and fast mixing strategy to enhance the thermal stability of polyacrylamide by adding common poloxamers to form the interpenetrating network hydrogel. The blending model of three synthetic polyacrylamides (cationic, anionic, and nonionic) and poloxamers was first established, and then the interaction process between them was simulated by all-atom molecular dynamics. In the results, it was found that the hydrogen bonding between the amide groups on all polymers and the oxygen-containing groups (ether and hydroxyl groups) on poloxamers is very strong, which may be the key to improve the high temperature resistance of the hydrogel. Subsequent rheological tests also showed that poloxamers can indeed significantly improve the stability and viscosity of nonionic polyacrylamide containing only amide groups at high temperatures and can maintain a high viscosity of 3550 mPa·S at 80 °C. Transmission electron microscopy further showed that the nonionic polyacrylamide/poloxamer mixture further formed an interpenetrating network structure. In addition, the Fourier transform infrared test also proved the existence of strong hydrogen bonding between the two polymers. This work provides a useful idea for improving the properties of polyacrylamide, especially for the design of high temperature materials for physical blending.