关键词: 小龙虾；冻结；冻藏；脂质氧化

Abstract: Red swamp crawfish were blanched, vacuum packaged, frozen at three different temperatures (?20, ?40 and ?55 ℃) until the internal temperature reached ?15 ℃, and stored at two different temperatures (?20 and ?40 ℃) for up to 24 weeks. The fat and free fatty acids (FFAs) contents, fatty acid composition, peroxide value (POV), and thiobarbituric acid reactive substance (TBARS) value of crawfish meat were measured to investigate the effect of freezing temperature and frozen storage temperature on lipid oxidation. The results showed that as storage time prolonged, the contents of fat, unsaturated fatty acids (UFAs), and polyunsaturated fatty acids (PUFAs) decreased significantly (P < 0.05), while the contents of FFAs and saturated fatty acids (SFAs) as well as POV and TBARS values increased significantly (P < 0.05). At the same frozen storage temperature, the POV and TBARS values of crayfish meat frozen at –20 ℃ were significantly higher than those of crayfish meat –40 and –55 ℃, while there was not a significant difference in FFAs contents or fatty acid composition; at the same frozen temperature, the fat and FFAs contents, POV, and TBARS values of crayfish meat stored at –20 ℃ were significantly higher than those of crayfish meat stored at –40 ℃, but the contents of UFAs and PUFAs during storage at –20 ℃ were slightly lower than at –40 ℃. In addition, SFAs contents during storage at –20 ℃ was higher than, but not significantly different from, those during storage at –40 ℃. These results indicated that freezing at –40 or –55 ℃ and frozen storage at –40 ℃ alleviated the degree of hydrolysis and oxidation of lipids from crayfish meat.

Key words: red swamp crawfish; freezing; frozen storage; lipid oxidation