草莓多糖树脂法脱色工艺优化及其化学性质研究

通过不同大孔树脂对草莓多糖脱色率、保留率和选择系数筛选效率最高的大孔树脂进行草莓多糖脱色参数优化,对草莓多糖的化学成分、单糖组成、分子量、光谱特性、抗氧化活性以及α-葡萄糖苷酶、α-淀粉酶的抑制作用进行研究。结果表明,NKA-9大孔树脂效率最高,其最优脱色参数为:样品初始浓度30 mg/mL,时间60 min,温度50 ℃,pH8.0。动态吸附试验表明当上样液体积和上样液流速分别为4.5 BV、3.0 BV/h时,草莓多糖脱色率、保留率和选择系数分别为91.24%±1.32%、78.86%±1.21%、8.24%±0.21%。NKA-9大孔树脂可有效吸附草莓多糖色素,但是脱色处理后草莓多糖抗氧化能力降低。草莓多糖是一种酸性杂多糖,主要由糖(78.23%±0.56%,w/w)、糖醛酸(8.56%±0.19%,w/w)、蛋白质(6.14%±0.63%,w/w)组成。草莓多糖由鼠李糖、阿拉伯糖、半乳糖、葡萄糖、果糖、半乳糖醛酸、葡萄糖醛酸组成,物质的量比为1.00:0.67:0.69:0.80:0.65:0.29:0.69。草莓多糖对α-葡萄糖苷酶和α-淀粉酶具有抑制活性,动力学分析结果表明草莓多糖对α-葡萄糖苷酶和α-淀粉酶的抑制类型分别为混合型抑制特征和非竞争性抑制类型,脱色处理后草莓多糖对酶抑制活性显著增强。

Optimization of Decoloration Process by Macroporous Resins and Its Chemical Properties of Strawberry Polysaccharides

The decolorization parameters of strawberry polysaccharides(SP)were optimized by different macroporous resins with the highest decolorization rate,retention rate and selection coefficient.The chemical composition,monosaccharide composition,molecular weight,spectral characteristics,antioxidant activity and inhibition ofα-glucosidase andα-amylase of strawberry polysaccharides were studied.The results suggested that NKA-9 resin offered better efficiency than other tested resins.The optimal decoloration parameters of NKA-9 resin were obtained as follows:Sample initial concentration of 30 mg/mL,static decoloration time of 60 min,temperature of 50℃,pH value of 8.0,dynamic decoloration processing volume of 4.5 BV with the flow rate of 3.0 BV/h.Decoloration ratio,PSTS recovery ratio and selectivity coefficient were 91.24%±1.32%,78.86%±1.21%and 8.24%±0.21%respectively.Pigment impurities were successfully removed from SP solutions after treated by NKA-9 resin,but decoloration treatment decreased the antioxidant ability of SP.SP was an acidic heteropolysaccharide which mainly contained carbohydrates(78.23%±0.56%,w/w),uronic acids(8.56%±0.19%,w/w)and proteins(6.14%±0.63%,w/w).SP was composed of rhamnose,arabinose,galactose,glucose,fructose,galacturonic acid and glucuronic acid with mass ratio of 1.00∶0.67∶0.69∶0.80∶0.65∶0.29∶0.69.SP exhibited inhibitory activities againstα-glucosidase in a mixed inhibition type,and againstα-amylase in an uncompetitive inhibition type.The enzyme inhibitory effect was enhanced significantly by decoloration.