Advantages of liquid nitrogen freezing in long‐term frozen preservation of hairtail (Trichiurus haumela): Enzyme activity, protein structure, and tissue structure

Abstract

This study aimed to investigate the effects of liquid nitrogen freezing (LNF) in long‐term frozen preservation of hairtail. Fresh hairtail was frozen by liquid nitrogen or cold air and stored at −20°C or −80°C for up to 120 days. The contents of carbonyl, TCA‐soluble peptides, AG and NAG enzyme activities increased, whereas Ca2+‐ATPase, Mg2+‐ATPase activity and the contents of sulfhydryl group decreased with the storage time increased. The activities of cathepsin B and B + L could be inhibited by low temperatures in the initial 40 days. However, the inhibition gradually weakened as the storage time increased. Protein surface hydrophobicity increased and reached a peak of 480.23 on day 60 with a subsequent fluctuant decrease. The α‐helix and β‐sheet structures of myofibrillar protein decreased, while the β‐turn and random coil structures increased. And the texture degradation occurred in all the tested four groups. The muscle fibers begun to break in cold air freezing (CAF) group after storage of 60 days. After a storage period of 120 days, large holes appeared in meat sample of CAF group. The muscle fibers of the LNF groups were kept much more complete than that of the CAF groups, indicating the advantages of LNF. Practical Application In this study, the advantages of liquid nitrogen freezing (LNF) on the quality of hairtail during long‐term frozen preservation were showed by enzyme activity, protein structure and tissue structure. Although LNF causes inevasible damage to the fish meat, the ice crystals during freezing were rather small and distributed homogenously due to fast freezing rate. Thus, the mechanical damage to muscle was much lower than that of the cold air freezing (CAF), showing great advantages of LNF. Liquid nitrogen was recommended for pre‐frozen of hairtail before frozen storage to maintain the quality of hairtail. These results could provide theoretical guidance for the applying of LNF on the hairtail processing for the quality maintenance of hairtail whilst aiming to get maximum nutritional benefits. This knowledge can also be widely applicated in other fishery products preservation.

Effects of single-, dual-, and multi-frequency ultrasound-assisted freezing on the muscle quality and myofibrillar protein structure in large yellow croaker (Larimichthys crocea)

“…Amino acids such as lysine, proline, and arginine are easily oxidized into semialdehyde under the action of reactive oxygen species and metal ions, accounting for most of the total carbonyl contents ( Li et al, 2021 ). Hu et al (2021) discovered that the carbonyl content of hairtail MP had an increase after liquid nitrogen quick-freezing, confirming the oxidation of frozen fish protein. The carbonyl content of IF was higher than that of UAF samples significantly.…”

Effects of Low-Frequency Electromagnetic Field on the Physicochemical Properties of Freeze–Thawed Mongolian Cheese

“…The reversibility of all freeze–thawed cheeses is significantly lower than the fresh cheese due to the different degrees of damage and the low-temperature denaturation of protein. Studies have shown that ultra-low-temperature freezing can change the secondary and tertiary structure of a protein, and then affect the quality of fish [ 19 ]. Generally speaking, the stronger the structural integrity, the higher the recovery.…”

Preparation and Characterization of a Biodegradable Film Using Irradiated Chitosan Incorporated with Lysozyme and Carrageenan and Its Application in Crayfish Preservation

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