响应面优化金丝小枣碱提多糖工艺及其抗氧化活性研究

Optimization of Alkali Extraction Process of ‘Jinsixiaozao’ Polysaccharide by Response Surface Methodology and Its Antioxidant Activity

以金丝小枣为原料,通过单因素考察提取温度、时间、料液比和NaOH浓度对多糖得率的影响,在此基础上进行Box-Behnken试验来优化碱提多糖的提取工艺,并对其进行总糖含量、扫描电镜、红外光谱及抗氧化活性测定。结果表明,碱提多糖最佳工艺为:料液比1:35(g/mL),提取温度80℃,提取时间120 min,NaOH浓度为0.2 mol/L,在此条件下多糖的得率为11.44%,总糖含量为69.39%。扫描电镜表明其具有不规则块状结构,内部紧实;红外光谱表明枣碱提多糖具有C=O和C-H等酸性多糖的特征吸收峰。抗氧化活性实验表明,碱提多糖具有一定清除自由基的能力,对DPPH和超氧阴离子自由基的IC_(50)分别为1.201 mg/mL和1.176 mg/mL。此研究为进一步开发枣多糖功能性食品及研究碱提多糖的构效关系提供参考。

In this experiment,‘Jinsixiaozao’ fruit was used as raw material,the effects of extraction temperature,time,solid-liquid ratio and NaOH concentration on the yield of polysaccharide were investigated by single factor test.On this basis,Box-Behnken experiment was carried out to optimize the extraction process of alkali extracted polysaccharides.Its total sugar content,scanning electron microscopy,infrared spectrum and antioxidant activity were determined.The results showed that the optimal conditions were solid-liquid ratio 1:35(g/mL),extraction temperature 80 ℃,extraction time 120 min,and NaOH concentration 0.2 mol/L,the polysaccharides yield was 11.44% with total sugar content of 69.39%.Scanning electron microscopic observations showed that it had irregular block structure with compact inside.The infrared spectrum showed that the alkali extracted polysaccharide of jujube had the characteristic absorption peaks of acid polysaccharides such as C=O and C-H.The antioxidant activity experiments showed that the alkali extracted polysaccharide had a certain ability to scavenge free radicals,and the IC_(50)for DPPH and superoxide anion free radicals were 1.201 mg/mL and 1.176 mg/mL,respectively.This study provides a reference for further developing functional foods of jujube polysaccharides and studying the structure-activity relationship of alkali extracted polysaccharides.