超声波辅助提取玉木耳多糖及其抗氧化活性分析

以玉木耳为原料,考察液料比、超声功率、超声温度和超声时间对多糖得率的影响,在单因素试验基础上,通过响应面分析法优化提取工艺条件,采用傅里叶红外光谱(FT-IR)对多糖结构进行初步表征,并通过测定玉木耳多糖清除1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基能力、铁离子还原能力(FRAP 法)和氧自由基清除能力(ORAC 法)研究其体外抗氧化活性。结果表明,超声波辅助法提取玉木耳多糖最优工艺为:液料比40∶1 mL/g,超声功率210 W,超声温度62 ℃,超声时间29 min,此工艺条件下玉木耳多糖的得率为7.43%;玉木耳多糖显示出多糖的典型特征吸收峰,是以β-糖苷键为主的吡喃型多糖;玉木耳多糖清除DPPH自由基IC₅₀值为1.445 mg/mL,FRAP值和ORAC值分别为35.14±0.16 mmol Trolox g-1和0.627 mg Trolox mg-1,具有较好的抗氧化能力,可作为天然抗氧化剂应用。

Ultrasound Assisted Extraction of Polysaccharides from Auricularia cornea Ehrenb. and Its Antioxidant Activity Analysis

Optimization of the extraction of polysaccharide from Auricularia cornea Ehrenb. for higher polysaccharide yield was carried out using one-factor-at-a-time method and response surface methodology. Solvent-to-solid ratio,ultrasonic power,ultrasonic temperature and ultrasonic time were used as independent variables. FT-IR was used to preliminary characterize the polysaccharide structure. The in vitro antioxidant activity of Auricularia cornea Ehrenb. polysaccharides was investigated by measuring total reducing power and scavenging activities against 1,1-diphenyl-2-trinitrophenylhydrazine(DPPH),iron ion reduction ability(FRAP)and oxygen radical scavenging ability(ORAC). The results showed that the optimum extraction conditions were found to be extraction at 210 W,62 ℃ for 29 min with a solvent-to-solid ratio of 40∶1 (mL/g). Experiments conducted under these conditions gave a polysaccharide yield of 7.43%. Polysaccharides had the characteristic absorption peak of polysaccharide and proved to be β-pyranose. The IC₅₀ against the DPPH free radical of the Auricularia cornea Ehrenb. polysaccharides was 1.445,and the FRAP and ORAC values were 35.14±0.16 mmol Trolox g-1and 0.627 mg Trolox mg-1,which had good antioxidant capacity and could be used as natural antioxidants.