氧化条件下茶多酚对猪肉肌原纤维蛋白理化和凝胶特性的影响

Effect of Tea Polyphenols on Physicochemical and Gel Properties of Pork Myofibrillar Protein under Oxidative Conditions

研究茶多酚质量浓度(0、0.02、0.2、1.0?mg/mL)对羟自由基氧化体系中猪肉肌原纤维蛋白侧链结构、凝胶保水性和水分分布状态的影响。结果表明,氧化处理后未加茶多酚的0?mg/mL组与空白对照组相比,游离巯基含量显著减少,表面疏水性和二聚酪氨酸含量显著增加,内源色氨酸荧光强度降低,保水性显著下降,自由水含量显著增加(P<0.05)。氧化处理后,随着茶多酚质量浓度的增加,蛋白质游离巯基和内源色氨酸荧光强度逐渐增加,表面疏水性呈下降趋势,凝胶保水性呈升高趋势,不易流动水含量显著增加,自由水含量显著降低(P<0.05)。在氧化体系中添加茶多酚,可以保护肌原纤维蛋白侧链结构,提高凝胶保水性。

The objective of this study was to investigate the effects of tea polyphenols (0, 0.02, 0.2 and 1.0 mg/mL) on the side chain structure, water-holding capacity (WHC) and water distribution state of myofibrillar protein (MP) in hydroxyl radical oxidation system. Results showed that oxidative stress to MP significantly decreased free sulfydryl content and WHC, significantly increased surface hydrophobicity, dityrosine content and free water content, and lowered endogenous tryptophan fluorescence intensity compared to the non-oxidized control (P < 0.05). Under oxidative conditions, free sulfydryl content and endogenous tryptophan fluorescence intensity gradually increased, surface hydrophobicity decreased, and WHC of MP gels rose with increasing concentration of tea polyphenols; immobilized water content significantly increased while free water content significantly declined (P < 0.05). Tea polyphenols can protect the side chain structure of MP and improve the WHC of heat-induced gels under oxidative conditions.