Injection of L-arginine or L-lysine before freezing delays the emulsifying and gelling properties deterioration of myofibrillar proteins of frozen porcine Longissimus lumborum muscle

This study aimed to investigate the effects of injecting L-arginine and L-lysine solution before freezing and after thawing on the emulsifying and gelling properties of myofibrillar proteins (MPs) of frozen porcine longissimus dorsi. The results showed that the pre-freezing injections were more effective in alleviating the decrease in emulsifying properties of MPs compared with the post-thawing injections, as evidenced by higher emulsion creaming index, oil droplet size, interfacial absorptive protein amount, and viscoelasticity. Additionally, the prefreezing injections could effectively mitigate the damage to the gelling properties of MPs, as evidenced by the formation of a homogeneous and compact gel network with stronger water retention, strength and chemical forces, as well as a higher proportion of non-flowing water, whereas the post-thawing injections could not. These results demonstrated that the injection of L-arginine and L-lysine solution before freezing could delay freezinginduced damage to the emulsifying and gelling properties of MPs, keeping the processing characteristics of frozen porcine.