宰后初期不同温度处理对鸭肉肌原纤维蛋白氧化及凝胶品质的影响

Effects of Different Temperature Treatments during the Early Postmortem Period on the Oxidation Characteristics and Gel Properties of Duck Myofibrillar Protein

研究不同温度处理对宰后初期鸭肉肌原纤维蛋白氧化及凝胶特性的影响。分别将鸭胸肉在不同温度处理(0、40℃分别孵育1 h),之后提取肌原纤维蛋白,测定蛋白氧化特征变化(羰基含量、巯基含量)以及对其凝胶特性(流变特性、质构和微观结构)的影响,并对蛋白特征使用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electropheresis,SDS-PAGE)进行分析。结果表明:与对照组(0℃)肌原纤维蛋白相比,热处理组(40℃)肌原纤维蛋白中的羰基含量升高,而巯基含量降低52.7%,蛋白凝胶的保水性降低14.1%,凝胶强度降低45.5%,三者均显著降低(P<0.05);两组间蛋白流变特性差异不明显,而SDS-PAGE分析发现,40℃处理组中部分肌浆蛋白附着于肌原纤维蛋白上,且凝胶网格结构整体较松散,说明在热处理过程中会伴随鸭肉肌原纤维蛋白发生氧化,从而使其凝胶特性受到影响。

The effects of different temperature treatments during the early postmortem period on the oxidation and gel properties of duck myofibrillar protein(MP)were studied.After postmortem aging for 1 h at different temperatures(0 and 40℃),MP was extracted from duck breast meat to measure changes in its oxidation characteristics(including carbonyl content and sulfhydryl content)and the effects thereof on its gel properties(including rheological properties,texture,and microstructure).Meanwhile,changes in MP composition were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE).The results showed that compared with the control group(0℃),the carbonyl content of MP in the heat-treated group(40℃)significantly increased,while the free sulfhydryl content decreased by 52.7%,the waterholding capacity(WHC)of MP gel decreased by 14.1%and the gel strength decreased by 45.5%;all these decreases were significant(P<0.05).There was no significant difference in protein rheological properties between the two groups;however,SDS-PAGE analysis indicated that sarcoplasmic proteins were partially attached to myofibrils in the 40℃ treatment group and the gel network structure was loose overall.These results indicated that the oxidation of duck MP can occur during heat treatment,which will affect its gel-forming capacity.