羧甲基化改性对不同分子量水溶性大豆多糖乳化性的影响

目的研究羧甲基化改性对不同分子量水溶性大豆多糖(soluble soybean polysaccharides,SSPS)乳化性的影响,探索进一步改善水溶性大豆多糖乳化性的方法。方法从豆渣中提取水溶性大豆多糖,使用超滤法分离,获得两种不同分子质量的多糖组分(L-低分子质量,H-高分子质量),分别对SSPS(未分离)、L和H进行羧甲基化改性,通过调节改性条件获得两种不同取代度(D-低取代度,G-高取代度)的水溶性大豆多糖。以不同的水溶性大豆多糖为乳化剂制备乳化液(O/W),对其乳化活性、乳化稳定性和乳化液显微结构进行分析。结果改性前后SSPS(未分离)、L和H的乳化性强弱顺序均为HSSPS(未分离)L;SSPS(未分离)和H的乳化活性在改性之后显著减弱(P0.05),且取代度越高乳化活性越弱,而L的乳化活性在改性之后增强,且取代度越高乳化活性越强;SSPS(未分离)和L的乳化稳定性在改性之后显著减弱(P0.05),但在取代度升高后二者的乳化稳定性又有所改善;H的乳化稳定性在改性之后显著减弱(P0.05),且取代度越高乳化稳定性越弱。结论高分子质量水溶性大豆多糖的乳化性优于低分子质量多糖,且这一规律不受改性的影响。在本试验条件下,羧甲基化改性对不同水溶性大豆多糖乳化性的影响不同,对乳化性的改善有一定的积极作用。

Effects of carboxymethylated modification on emulsibility of soluble soybean polysaccharides with different molecular weight

Objective To research effects of carboxymethylated modification on emulsibility of soluble soybean polysaccharides with different molecular weight and explore the method of further improving the emulsification of soluble soybean polysaccharides. Methods Soluble soybean polysaccharides were extracted from soybean residue and then separated by ultra filtration method to prepare fragments with different molecular weight. SSPS (without separation), L and H were modified by carboxymethylated modification, respectively. Different degrees of substitution (low D, high G) were achieved by adjusting the conditions of modification. Different soluble soybean polysaccharides were selected as emulsifier to prepare emulsion (O/W) and the emulsifying activity, emulsifying stability and emulsion microstructure were analyzed. Results The results showed that no matter before or after modification, the emulsibility of H was the best, L was the worst, and SSPS (without separation) was intermediate. The emulsifying activity of SSPS (without separation) and H weakened significantly after modification (P<0.05), and the higher the degree of substitution, the weaker the emulsifying activity. The emulsifying activity of L strengthened after modification, and the higher the degree of substitution, the stronger the emulsifying activity. The emulsifying stability of SSPS (without separation) and L weakened significantly after modification (P<0.05), while with the increase of substitution degree the emulsifying stability was improved. The emulsifying stability of H was weakened significantly after modification (P<0.05), and the higher the degree of substitution, the weaker the emulsifying stability. Conclusion The emulsibility of the high molecular weight fragment are better than that of the low molecular weight fragment, and the law is not affected by modification. Under the condition of this experiment, effects of carboxymethylated modification on the emulsibility of different soluble soybean polysaccharides are different and there are certain positive effects on improvement of the emulsibility. Modification cannot improve the emulsifying activity of SSPS (without separation) and H, while, can improve that of L. Modification cannot improve the emulsifying stability of H and the effect of modification on the emulsifying stability of SSPS (without separation) and L is associated with the substitution degree. The low degree of substitution will weaken the emulsifying stability, while, the high degree of substitution is helpful to enhance the emulsifying stability.