桦褐孔菌多糖提取条件的优化及其抗氧化活性分析

摘要

以桦褐孔菌子实体为原料,用水提和碱提的方法提取桦褐孔菌粗多糖,利用响应面优化实验对粗多糖的提取工艺进行优化,并对桦褐孔菌水溶多糖及碱溶多糖进行抗氧化活性测定.结果表明,水溶多糖的最佳提取条件为提取温度85℃、提取时间4.77 h、液料比43:1,在此条件下,水溶粗多糖得率为16.86％ (RSD =0.004 8);碱溶多糖的最佳提取条件为提取时间4.26 h、NaOH浓度为0.6 mol·L-1、液料比28:1,在此条件下,碱溶粗多糖得率为28.64％(RSD=0.051 9).水溶粗多糖及碱溶粗多糖中的多糖含量分别为10.78％和7.80％.桦褐孔菌碱提多糖的总还原力明显高于水提多糖,并且碱提多糖清除羟基自由基的能力亦远高于水提多糖,在桦褐孔菌多糖浓度为2.5 mg·mL-1时,碱提多糖的羟基自由基清除率能达到80.28％,水提多糖为51.19％.碱提多糖在发挥抗氧化活性方面具有很大的潜能,可为桦褐孔菌的开发利用提供理论依据.%Crude polysaccharides,Inonotus obliquus were obtained with water extraction or alkali extraction.The extracting conditions were optimized with response surface methodology (RSM).The total antioxidant capacity and hydroxyl free radical scavenging activity were indexes to test the antioxidant activity of water-soluble polysaccharide and alkali-soluble polysaccharide.The experimental results showed that the optimized extraction conditions for water-soluble polysaccharide were extraction temperature of 85 ℃,extraction time of 4.77 h and water/solid ratio of 43:1.Under the above conditions,the yield of watersoluble crude polysaccharide was 16.86％.The optimum extracting conditions for alkali-soluble polysaccharide were extraction time of 4.26 h,NaOH concentration of 0.6 mol · L-1 and water/solid ratio of 28:1.Under the above conditions,the yield of alkali-soluble crude polysaccharide was 28.64％.The contents of polysaccharides in the water-soluble polysaccharide and alkali-soluble polysaccharide were 10.78％ and 7.80％,respectively.The total antioxidant capacity of alkali-soluble polysaccharide,Inonotus obliquus was significantly higher than that of water-soluble polysaccharide.The hydroxyl free radicalscavenging activity of alkali-soluble polysaccharide was higher than that of water-soluble polysaccharide.When the concentration of polysaccharides was 2.5 mg · mL-1,the scavenging rates of hydroxyl free radical were 80.28％ and 51.19％,respectively for alkali-soluble polysaccharide and water-soluble polysaccharide.Alkaline polysaccharides have great potentials in antioxidant activity,which provides a theoretical basis for development and utilization of Inonotus obliquus.