Pigskin Collagen-Derived Antifreeze Peptides as Clean-Label Cryoprotectants: Inhibition of Ice Recrystallization and Suppression of Oxidative Deterioration in Heme-Rich Pork Sausages

Frozen red meat products face dual challenges: structural damage from ice recrystallization and subsequent oxidative deterioration driven by endogenous pro-oxidants in heme-rich matrices. This study investigated the efficacy of pigskin collagen-derived antifreeze peptides (APPs) as clean-label cryoprotectants in pork sausages. In vitro characterization confirmed distinct thermal hysteresis (0.51 °C) and potent ice recrystallization inhibition. In the sausage system, 6% APPs overcame ionic screening effects, reducing thawing loss to 4.87% (vs. 7.51% in control) and cooking loss to 14.59%, significantly outperforming commercial phosphates in moisture retention. Low-field NMR revealed that APPs stabilized the actomyosin hydration shell, maintaining the immobilized water proportion (P21) at 93.67% (vs. 88.50% in control) and inhibiting conversion of immobilized water into free water. Furthermore, APPs suppressed oxidative deterioration, limiting protein carbonyl content to 3.08 nmol/mg (vs. 3.71 nmol/mg in control), supporting a “physical–chemical cascade” mechanism whereby superior microstructural preservation mitigates downstream oxidative deterioration. Despite a trade-off in textural resilience (0.37 vs. 0.44), APPs function as specialized “Ice-Structure Stabilizers” offering a robust clean-label strategy for preserving heme-rich meat products.