Cryoprotective effects of glycerol on the structure and function of myofibrillar proteins in pork patties with multiple freeze-thaw cycles

Abstract

This study investigated the cryoprotective effects of glycerol on myofibrillar proteins (MPs) in pork patties subjected to repeated freeze–thaw cycles. Compared with the control, glycerol markedly inhibited the reduction in protein solubility and absolute zeta potential while suppressing the increase in turbidity and average particle size of MPs. It effectively delayed the increase of carbonyl group and surface hydrophobicity, the decline in total sulfhydryl groups and intrinsic fluorescence intensity, and the conformational transition from α-helix to β-sheet. Glycerol also mitigated the loss of whiteness, textural strength, and intermolecular interactions and retarded the thermal denaturation of MP molecules. Moreover, it reduced cooking loss and microstructural degradation in MP gels. In emulsification systems, glycerol alleviated the decline in emulsifying activity and stability, limited the increase in creaming index, and prevented oil droplet coalescence in MP–soybean oil emulsions. Overall, glycerol preserved the gelation and emulsification functionality of MPs by delaying protein aggregation and conformational disruption, thereby maintaining the structural integrity and quality of pork patties during multiple freeze–thaw cycles.