咖啡生豆多糖提取及抗氧化活性

Extraction of polysaccharide from green coffee beans and its antioxidant activity

目的:为咖啡中多糖成分的研究和天然活性多糖的开发提供基础数据。方法:研究了云南小粒咖啡生豆多糖(GBP)的水提工艺和抗氧化活性。应用响应面法对咖啡生豆多糖提取工艺进行优化;运用傅里叶变换红外光谱(FT-IR)和扫描电镜(SEM)共同鉴定和表征咖啡生豆多糖的结构特点。采用DPPH自由基、ABTS自由基清除试验和FRAP法评估咖啡生豆多糖体外抗氧化能力。结果:咖啡生豆多糖水提法的最佳工艺条件:提取温度59℃、提取时间45 min、液料比(V水∶m咖啡生豆)21∶1 (mL/g)、浓缩体积1/8及乙醇体积分数75%,该条件下咖啡生豆多糖得率达9.56%。多糖样品经红外光谱和电镜扫描显示咖啡生豆是表面呈不规则的孔状结构的多糖。咖啡生豆多糖对DPPH自由基、ABTS自由基清除能力分别为2.32 mg/mL(IC50)、0.011 mmol Trolox/g GBP,铁还原能力为0.95 mmol Fe2+/g GBP。结论:咖啡生豆多糖是具有抗氧化活性的不规则孔状结构多糖,具有进一步研究和开发的价值。

Objective:This study provided basic data for the investigation of polysaccharides in coffee and the development of natural active polysaccharides.Methods:The water extraction method and antioxidant activity of green coffee beans polysaccharide(GBP)from Yunnan province.Response surface method was used to optimize the extraction process of polysaccharide from coffee bean.Fourier transform infrared spectroscopy(FT-IR)and scanning electron microscopy(SEM)were used to identify and characterize the structure of polysaccharide from coffee bean.DPPH,ABTS free radical scavenging assay and FRAP assay were used to evaluate the antioxidant capacity of coffee bean polysaccharide in vitro.Results:The optimal extraction conditions were as follows:extracting at 59℃for 45 min,liquid-solid ratio(V W∶m)21∶1(mL/g),concentrated volume 1/8 and ethanol volume fraction 75%.Under the control of these conditions,the yield of polysaccharides from coffee beans reached 9.56%.The results of FT-IR and electron microscopy showed that the polysaccharide of coffee bean had irregular pore structure.The DPPH scavenging capacity and ABTS radical scavenging capacity of coffee bean polysaccharide was 2.32 mg/mL(IC 50)and 0.011 mmol Trolox/g GBP,respectively.The iron reducing capacity of coffee bean polysaccharide was 0.95 mmol Fe 2+/g GBP.Conclusion:Polysaccharide derived from green coffee beans is a kind of polysaccharide with irregular pores and antioxidant activity,which is valuable for further research and development.