Preservation mechanism of liquid nitrogen freezing on crayfish ( Procambarus clarkia ): Study on the modification effects in biochemical and structural properties

Abstract

The objective of this study was to investigate the advantages of liquid nitrogen freezing (LNF) over normal contact freezing (NCF) and individual quickly freezing (IQF). The quality attributes of LNF on crayfish (Procambarus clarkia) were characterized by biochemical and structural properties. Compared with NCF and IQF, LNF presented lower total viable counts (TVC) value of 5.83 log(CFU/g), thiobarbituric acid (TBA) value of 0.74 mg/kg, total volatile basic nitrogen (TVB-N) content of 23.43 mg/100 g and α-glucosidase and β-acetyl glucosaminidase enzyme activities. SDS-PAGE patterns confirmed less protein denaturation in LNF. Meanwhile, texture parameters analysis indicated LNF held texture quality better, while scanning electron microscope patterns revealed that muscle fibers in LNF were more uniform. The mathematical models exhibited the significant correlation among biochemical and structural properties. Therefore, LNF was a promising freezing process for crayfish preservation, due to the formation of small intracellular ice crystals and maintenance of cell integrity. Novelty impact statement The LNF which was considered as a promising freezing method was applied in crayfish preservation. The preservation behavior of LNF was characterized and the related protective mechanism was illustrated. The mathematical models were established to clarify the inner relationship between freezing conditions and quality attributes.