Effect of blanching treatment on oyster meat quality during refrigeration and frozen storage

Oyster meat is prone to quality deterioration during storage, and blanching may kill most microorganisms and inactivate enzymes, thereby delaying the quality deterioration of raw materials during storage. However, there is limited research on heat treatment in oyster raw material storage. Thus, taking the unblanched fresh oyster meat (CK) and blanched oyster meat (Bo) stored at 4 ℃ and −20 ℃ as research subjects, we comprehensively analyzed the safety, appearance, texture and flavor indexes, and quality changes of CK and Bo during storage at 4 ℃ and −20 ℃. The results show that the quality deterioration of both CK and Bo existed under the two storage conditions, and the quality deterioration degree of CK was more obvious than that of Bo during storage. During the refrigeration process at 4 ℃, the odor and TVB-N of the two groups changed significantly, and the TVB-N in the CK group reached the highest value of 11.68 mg·100 g⁻¹ on the 4^th day of storage. During the freezing at −20 ℃, the TVB-N values of both groups showed an upward trend, but the values of the Bo group were significantly lower than those of the CK group (p<0.05). The lactate content of both groups increased with the extension of storage time, and the CK group reached the highest of 2.78 mg·100 g⁻¹ on the 30^th day under −20 ℃ storage conditions. During 4 ℃ storage, the main flavor amino acids (Glycine, alanine, glutamic acid and aspartic acid) in the Bo group generally showed an upward trend, while the regularity in the CK group was not obvious. During −20 ℃ storage, the main flavor amino acids showed a decreasing trend, and the decline degree of the Bo group was smaller than that of the CK group. The results provide a theoretical basis for the quality control of oyster raw materials before processing.