Effect of Ultra-high Pressure and Blanching Pretreatment on the Quality of Frozen Procambarus clarkii Meat

The effects of ultra-high pressure (200 MPa, 5 min) and blanching (100℃, 4 min) on the quality of Procambarus clarkii were studied during frozen storage at -18℃. The physical and chemical (TVB-N), thiobarbituric acid (TBA), sensory (pH value, texture, color) and protein (myofibrillar protein, mercapto, carbonyl, Ca²⁺-ATPase, surface hydrophobicity, intrinsic fluorescence) were measured at 0, 4, 8, 12 and 24 weeks of storage, respectively. The effects of different pretreatments on the quality of Procambarus clarkii could be evaluated during frozen storage. The results showed that the values of TBA and TVB-N increased significantly (P<0.05), the pH value showed a downward trend, and the physical and chemical quality decreased significantly with the increase of frozen storage time. The color and texture of the treated group were better than those of the control group, it had a great influence on the texture value. The effect of ultra-high pressure pretreatment on the texture and color of the sample was less than that of the scalding group, which indicated that the sample had the best sensory quality after scalding. The myofibrillar protein was not extracted successfully in the scalding group due to the prolonged scalding time. Ultra-high pressure treatment promoted the oxidation of myofibrillar protein to some extent. During the whole storage period, the myofibrillar protein, sulfhydryl group and Ca²⁺-ATPase decreased significantly (P<0.05), carbonyl group and surface hydrophobicity increased significantly (P<0.05), however the endogenous fluorescence intensity of myofibrillar protein increased by λ_max in the first 4 weeks, a red-shift phenomenon occurred, and λ_max decreased with storage time, resulting in a blue-shift phenomenon. According to analysis indicators, compared with the effect of blanching pretreatment, ultra-high pressure pretreatment promotes the oxidation of protein to a certain extent, and various physical and chemical indicators indicate that blanching pretreatment delays protein oxidation.