为探讨氧化对兔肉肌原纤维蛋白结构的氧化修饰及对肌原纤维蛋白乳化性质和凝胶质构特性的影响,本文利用0~10.0 mmol/L 2,2'-盐酸脒基丙烷(2,2'-azobis(2-amidinopropane)dihydrochloride,AAPH)热解产生的烷过氧自由基对兔肉肌原纤维蛋白进行氧化处理。结果表明,随着AAPH浓度的增加,兔肉肌原纤维蛋白游离巯基含量、内源性荧光强度和蛋白乳化稳定性不断减小,而羰基含量、二聚酪氨酸含量、蛋白粒径、乳化活性显著增加(P<0.05),表面疏水性则呈现先增后减再增的趋势。聚丙烯酰胺凝胶电泳(polyacrylamide gel electrophoresis,SDS-PAGE)结果显示,低浓度AAPH(0~1.0 mmol/L)和高浓度(10.0 mmol/L)分别诱导了蛋白的聚集和裂解,这些结构的改变引起了肌原纤维蛋白凝胶性质的改变。适度的氧化改性(AAPH 0~1.0 mmol/L)能提高兔肉肌原纤维蛋白凝胶的质构特性,而进一步氧化(AAPH 1.0~10.0 mmol/L)则显著降低了凝胶的性能(P<0.05)。因此,烷过氧自由基的氧化修饰能显著影响兔肉肌原纤维蛋白的结构和乳化凝胶性质(P<0.05)。
To investigated the effects of oxidative modifications on rabbit meat myofibrillar protein(MP)structures as well as their emulsifying properties and gel texture properties caused by oxidation. In this paper,oxidative treatment of rabbit meat myofibrillar protein was carried out using 0~10.0 mmol/L AAPH-derived(2,2'-azobis(2-amidinopropane)dihydrochloride)peroxyl radicals. The results showed that with the increasing of AAPH concentration,the free thiols content,intrinsic fluorescence intensity and protein emulsification stability of rabbit meat MP decreased,while the carbonyl content,bityrosine content,protein particle size and emulsifying activity increased(P<0.05),the surface hydrophobicity tends to increase first and then decrease and then increase again. Results from polyacrylamide gel electrophoresis(SDS-PAGE)indicated that low concentration of AAPH(0~1.0 mmol/L)and relatively high concentration(10.0 mmol/L)induced aggregation and cleavage of the protein,respectively. These structural changes resulted in changes on the gel texture of myofibrillar protein.Moderate protein oxidation(AAPH 0~1.0 mmol/L)improved the texture properties of the gel of rabbit meat,while further oxidation(AAPH 1.0~10.0 mmol/L)significantly reduced the properties of the gel(P<0.05). Therefore,the oxidative modification of peroxyl radicals can significantly affect the structure,emulsification and gelability of rabbit meat MP(P<0.05).