超高压与热烫预处理对克氏原螯虾肉冻藏品质的影响

本文研究采用超高压(200 MPa,5 min)、热烫(100 ℃、4 min)两种预处理对克氏原螯虾冻藏(-18 ℃)期间品质变化的影响。贮藏期0、4、8、12、24周分别进行理化(挥发性盐基氮(TVB-N)、硫代巴比妥酸(TBA))、感官(pH、质构、色泽)与蛋白(肌原纤维蛋白、巯基、羰基、Ca²⁺-ATPase酶、表面疏水性、内源性荧光强度)等指标测定,综合评价两种预处理对克氏原螯虾冻藏期间品质变化影响。结果表明:随着冻藏时间的推移,TBA与TVB-N值显著性上升(P<0.05),pH整体呈下降趋势,理化品质明显下降;其中处理组的色泽、质构均优于对照组,且热烫组色泽较稳定,对质构值影响大。超高压预处理对样品质构与色泽影响小于热烫组,表明样品经热烫处理后感官品质最佳。由于虾热烫时间过长,导致热烫组的肌原纤维蛋白未提取成功。超高压处理一定程度上促进肌原纤维蛋白的氧化,整个贮藏期中,蛋白类指标:肌原纤维蛋白、巯基、Ca²⁺-ATPase酶活显著性下降(P<0.05),羰基、表面疏水性显著上升(P<0.05),而肌原纤维蛋白内源性荧光强度前4周λ_max增大,发生红移现象,随贮藏时间的推移λ_max下降,产生蓝移现象。综上所述,与热烫预处理效果相比,超高压预处理能够在一定程度上促进蛋白的氧化,而且各项理化指标均表明,热烫预处理能够延缓肌原纤维蛋白的氧化。

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.