提取方法对产朊假丝酵母β-葡聚糖性质的影响

摘要

以产朊假丝酵母(Candida utilis)为原料,采用高压微射流均质法、超声波法及复合酶解生物法对酵母细胞壁中的β-葡聚糖(yeast β-glucan,YG)进行提取(分别标为H-YG、U-YG和E-YG).比较了3?种方法提取β-葡聚糖的得率、纯度、分子质量分布、单糖组成等理化性质,并测定了3?种提取方法对样品抗氧化性和保湿性能的影响.结果表明:3?种方法提取的β-葡聚糖纯度都在96%以上,高压微射流均质法得到的H-YG得率和含量最高,分别为19.6%和97.5%;紫外光谱扫描显示多糖样品均不含核酸和蛋白质等杂质;单糖组成分析表明,3?种方法提取的β-葡聚糖样品均是由葡萄糖组成的均一多糖;采用高效体积排阻色谱与多角度激光光散射联用仪测定了3?种方法提取的β-葡聚糖的分子质量分布和多糖平均分子半径,表明3?种方法提取的β-葡聚糖的重均分子质量mw存在差异,分别为1.611×106、4.763×106、2.661×105?g/mol,多分散系数分别为1.025、1.686、1.362,平均分子半径分别为67.5、33.3、43.7?nm.抗氧化实验表明H-YG、U-YG和E-YG均具有一定的1,1-二苯基-2-三硝基苯肼自由基清除能力,显示了其抗氧化能力.保湿实验表明:H-YG、U-YG和E-YG都有明显的体外保湿性能,H-YG体外保湿效果在8～24?h内优于甘油;3?种方法提取的β-葡聚糖样品均对促进内源性天然保湿因子的生成效果显著,其中H-YG的促进作用最为明显.研究结果表明,不同的提取方法影响酵母β-葡聚糖的理化性质,进而影响其生物活性,可根据其不同特性应用于相应领域.%Three different methods: high pressure microfluidization, ultrasonic, dual enzymatic hydrolysis were employed to extract β-glucan from the cell walls of the yeast Candida utilis and the obtained extracts were designated as H-YG, U-YG and E-YG, respectively. The yields, purities, molecular mass distributions, and monosaccharide compositions of these β-glucans were compared. We also evaluated the effect of three extraction methods on the antioxidant activity and moisturizing properties of β-glucans. The results showed that the purities of β-glucan extracted by three methods were all above 96% and high pressure microfluidization gave the highest yield and purity of β-glucan of 19.6% and 97.5%, respectively. UV spectra showed that none of these β-glucans contained nucleic acids, proteins or other impurities. Monosaccharide composition analysis showed that all three β-glucans were homogenous polysaccharides composed of only glucose. The molecular mass distribution and the average molecular radius were measured by high-performance size exclusion chromatography and multi-angle laser light scattering, and the results indicated that the weight average molecular masses of H-YG, U-YG and E-YG were 1.611 ×106, 4.763 × 106and 2.661 × 105g/mol, the polydispersity coefficients were 1.025, 1.686 and 1.362 and the average molecular radii were 67.5, 33.3 and 43.7 nm, respectively. All three β-glucans showed DPPH radical scavenging capacity, suggesting their antioxidant potential. Furthermore, they had significant moisturizing properties in vitro, and the moisturizing effect of H-YG was better than that of glycerol in 8-24 h. All these β-glucans especially H-YG significantly contributed to promoting the generation of endogenous natural moisturizing factor. These findings demonstrated that different extraction methods affected physicochemical properties and bioactivity of yeast β-glucan, and could be applied to various fields according to their characteristics.