壳聚糖复合保鲜对草鱼肌肉蛋白质变化的影响

Effect of a Natural Preservative Combination Containing Chitosan on Changes in Muscle Proteins from Grass Carp during Cold Storage

肌肉蛋白质的理化变化是导致淡水鱼贮藏过程中品质下降的重要原因之一,为明确保鲜处理对草鱼肌肉蛋白质变化的影响,本实验将草鱼片分别以壳聚糖复合保鲜液(10 mg/mL壳聚糖+5 mg/mL茶多酚+2 000 U/mL溶菌酶)和无菌水(对照组)处理,通过对比分析草鱼冷藏过程中挥发性盐基氮(total volatile basic nitrogen,TVB-N)含量、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electropheresis,SDS-PAGE)图谱、分子质量分布、活性巯基含量及表面疏水性等蛋白质相关指标的变化,探讨壳聚糖复合保鲜处理对延缓草鱼肌肉蛋白质变化的作用。结果表明:冷藏过程中保鲜组草鱼各项蛋白质相关指标的变化均明显小于对照组,第6~9天差别尤为明显;保鲜处理能抑制TVB-N含量上升、活性巯基含量下降及表面疏水性的变化,表明保鲜组蛋白质分解、氧化、变性程度较低;保鲜组蛋白质的SDS-PAGE和高效液相体积排阻色谱的谱图变化较慢,也证实了保鲜处理在对抑制蛋白质的降解和结构性质变化方面的作用。上述结果表明壳聚糖复合保鲜能一定程度上维持肌肉蛋白质的结构和性质的稳定,从而延缓冷藏过程中草鱼肌肉质量的下降。

Changes in the physicochemical properties of muscle proteins are among the leading causes of quality deterioration during the storage of freshwater fish. The effect of preservative treatment on changes in the physicochemical properties of muscle proteins from freshwater fish is not yet well understood nowadays. Therefore, in this study, two groups of grass carpfillets treated separately with a natural preservative combination of 10 mg/m L chitosan + 5 mg/m L tea polyphenol + 2 000 U/m L lysozyme and sterile water(control group) were analyzed and compared for changes in total volatile basic nitrogen(total volatile basic nitrogen(TVB-N) content, sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) pattern,molecular mass distribution, active sulfhydryl group content and surface hydrophobicity, with the aim of evaluating the effectiveness of the mixed preservative for preventing changes in fish muscle proteins. The results showed that the preservative treatment group exhibited lesser changes in any of the protein properties than did the control group, especially from Day 6 to 9 of cold storage. The preservative treatment prevented the increase in TVB-N content and the decrease in active sulfhydryl group content as well as the change in surface hydrophobicity, indicating reduced protein breakdown,oxidation and denaturation. The slower change in SDS-PAGE and size exclusion-high-performance liquid chromatography profiles provided further evidence supporting the role of the preservative treatment in inhibiting protein degradation and structural change. These results provided evidence that the mixed preservative can stabilize the structure and properties of grass fish muscle proteins to a certain extent and consequently prevent quality deterioration.