羧甲基茯苓多糖对酪蛋白pH稳定性与生物活性的调控与机制研究

Study on the regulation and mechanism of carboxymethyl pachymaran on pH stability and bioactivity of casein

中文关键词:  茯苓多糖  酪蛋白  聚集程度  抗糖化活性

英文关键词:pachymaran  casein  aggregation degree  anti-glycation

中文摘要:

      目的 探究羧甲基茯苓多糖以不同比例与酪蛋白复配时对酪蛋白稳定性、结构与理化性质以及生物活性的影响。方法 通过羧甲基衍生化, 提升茯苓多糖的溶解性并表征其结构; 以不同比例将羧甲基茯苓多糖与酪蛋白进行物理共混, 测定复合物在不同pH下的浊度、zeta电位、蛋白质溶解性、相图; 通过激光共聚焦显微镜和旋转流变仪比较不同酪蛋白样品在酸性条件下的聚集特性与理化特性; 通过自由基清除能力与非酶糖基化产物的抑制能力比较不同酪蛋白样品的生物活性。结果 本研究所得羧甲基茯苓多糖的分子量为2.43×105 g/mol, 通过取代度(0.84)和红外光谱中的羧甲基特征吸收峰可以确定羧甲基多糖的成功制备。当羧甲基茯苓多糖与酪蛋白共混后, 能够有效提高酪蛋白的pH稳定性, 显著影响了酪蛋白在酸性条件下的浊度、提高蛋白溶解性, 这可能是由于多糖-蛋白质间静电互作力影响了复合物分子的表面电荷分布。其中, 当二者以5:1 (w/w)复合时, 羧甲基茯苓多糖表现出最好的稳定效果。随后的结构与理化性质研究表明, 引入多糖, 特别当二者以5:1 (w/w)复合时, 复合物具有较低的聚集程度、表观黏度与模量, 表明此时复合物的凝胶网络结构具有更好的结构稳定性。生物活性结果表明, 复合物, 特别以5:1 (w/w)复合时, 表现出最强的抗氧化活性和非酶糖基化产物的抑制能力。结论 本研究所得羧甲基茯苓多糖-酪蛋白复合物在酸性环境下具有更好的结构稳定性与生物活性, 为稳定的酸性乳制品的开发与加工提供理论基础和技术支持。

英文摘要:

      Objective To investigate the effects of carboxymethyl pachymaran on the stability, structure, physicochemical properties and biological activity of casein at different ratios. Methods Pachymaran was derivatized with carboxymethyl groups to enhance its solubility, and its structural features were studied; carboxymethyl pachymaran was mixed with casein in different ratios, and the turbidity, zeta potential, protein solubility, and phase diagram of the complex were evaluated at different pH values; the aggregation degree and physicochemical properties of different casein-based samples were studied under acidic conditions using confocal laser microscopy and rotational rheometer; free radical scavenging ability and non-enzymatic glycation product inhibition ability of different casein-based samples were compared. Results The molecular weight of carboxymethyl pachymaran obtained in this study was 2.43×105 g/mol. The successful preparation of carboxymethyl pachymaran was determined by the degree of substitution (0.84) and the characteristic absorption peak of carboxymethyl group. When carboxymethyl pachymaran was mixed with casein, it could effectively affect the pH stability and reduce the turbidity of casein under acidic conditions, and its solubility was also enhanced. This might be due to the electrostatic interactions between polysaccharides and proteins affecting the surface charge distribution of the molecules. Among them, the best stabilizing effect was observed when carboxymethyl pachymaran was mixed with casein at 5:1 (w/w). Subsequent studies on the structure and physicochemical properties of the complex showed that with the introduction of polysaccharides, especially when they were mixed at a ratio of 5:1 (w/w), the aggregation degree, apparent viscosity and modulus of the complex were lower, indicating that its gel network structure had better stability. The biological activity results showed that the complex, especially when they were mixed at a ratio of 5:1 (w/w), exhibited the strongest antioxidant activity and non-enzymatic glycation product inhibition ability. Conclusion The carboxymethyl pachymaran-casein complex obtained in this study has better structural stability and biological activity in acidic environments, providing a theoretical basis and technical support for the development and processing of stable acidic dairy products.