解冻方式对中国对虾品质的影响

Freezing is the most effective storage method, thawing also plays an important role on the quality of samples after freezing. The effects of ultrasound-assisted thawing, water immersion thawing, air thawing and low-temperature thawing on the quality of Chinese shrimp were investigated in this paper. Protein carbonyl content, total sulfhydryl content, protein solubility and thiobarbituric acid reactive substances(TBARS) of the treated samples were measured to explore the influence of thawing methods on the oxidation of protein and fat, besides water holding capacity, color, texture of shrimp muscle and the microstructures. The results showed that ultrasound-assisted thawing had the fastest thawing rate, it took 4.3 min, and low-temperature thawing was the slowest which took 154.7 min. After the air thawing, protein carbonyl content was the highest which arrived 2.70 nmol/mg(P<0.05), total sulfhydryl content and protein solubility decreased, resulting in the protein oxidation of Chinese shrimp; total sulfhydryl content of Chinese shrimp thawed by ultrasound was higher(P<0.05), surface hydrophobicity of Chinese shrimp thawed by low-temperature was lower(P<0.05), the degree of protein oxidation of these two thawing methods were lower. Samples thawed by air had higher TBARS than those of other three thawing methods(P<0.05). From the perspective of muscle quality, after ultrasound-assisted thawing, a^* and b^* value did not significantly differ from the fresh control and the thawing process had little negative effect on the microstructure of muscle. Water immersion thawing induced some gaps between muscle fibers. There were the least thawing loss and cooking loss in low-temperature thawing, and microstructure in samples was closer to fresh control. However, air thawing significantly tore muscle fiber bundles and showed large gap between muscle fibers, resulting in the deterioration of the quality of Chinese shrimp. Considering thawing rate and quality control, ultrasound-assited thawing was a better thawing way.