Improving porcine meat quality during freezing with agaro-oligosaccharide and pigskin collagen peptides: A study on ice recrystallization and myofibrillar proteins structure.

Abstract

Single-component cryoprotectants rarely address degradation of frozen pork quality by both ice recrystallization and protein unfolding. A clean-label composite cryoprotectant (CAA: 1% agaro-oligosaccharide plus 3% pigskin collagen peptides, 10% v/w) was designed to synergistically suppress ice recrystallization and preserve myofibrillar proteins structure. Compared to 4% sucrose-sorbitol blend, CAA reduced the ice-crystal-to-tissue area ratio after 36 h at -40 °C by 48.75% and lowered thawing loss from 5.21% to 3.97%, while surface redness was held at 84.70% of the fresh level. Compared to untreated air-blast freezing samples, CAA increased storage modulus, locked β-turn structures and preserved the native Trp/Tyr micro-environment; low-field nuclear magnetic resonance showed a 2.97% increase in the peak of immobilized water and a 72.61% decrease in the peak of free water, confirming restricted water mobility within a compact, low-aggregated protein network. Thus, CAA outperformed commercial sucrose-sorbitol systems, offering a clean-label strategy to maintain fresh-like quality in frozen pork.