摘要
[目的]研究烘焙小粒咖啡豆多糖的组成和结构特征。[方法]以烘焙小粒咖啡豆为原料,采用响应面法优化热水浸提醇沉提取烘焙小粒咖啡豆多糖工艺条件;联合Sevag法、大孔树脂、纤维素及凝胶分离纯化多糖;采用苯酚硫酸法、福林酚法、NaNO_(2)-AlCl3-NaOH法及离子色谱法分析多糖中总糖、总酚、总黄酮及单糖组成;采用红外光谱(IR)、扫描电子显微镜(SEM)表征多糖的结构特征;同时评价其体外抗氧化活性。[结果]热水浸提醇沉提取烘焙小粒咖啡豆多糖的最佳工艺条件为提取温度80.4℃、提取时间48 min、液料比15.3∶1(mL/g),乙醇体积分数75%,此时多糖得率为(7.56±0.26)%。烘焙小粒咖啡豆粗多糖(RBP0)经过纯化得到5个以半乳糖(Gal)、鼠李糖(Rha)、葡萄糖(Glc)、阿拉伯糖(Ara)和甘露糖(Man)为主要单糖的多糖(RBP1、RBP2、RBP3、RBP4和RBP5)。烘焙小粒咖啡豆多糖在3300~3500,2900~3000,1600,1400~1300,1000 cm^(-1)附近有明显的多糖红外特征吸收;SEM显示烘焙小粒咖啡豆多糖是一系列具有紧致孔状结构的多糖,其中,RBP4呈密集且规则的多孔状结构。抗氧化活性测定结果显示,RBP0的抗氧化活性最强,其在0.1~0.5 mg/mL质量浓度范围内随样品质量浓度的升高而增强,对DPPH自由基的清除率由(1.53±0.32)%升高到(82.85±0.61)%;FRAP法测得铁离子还原能力由(0.39±0.00048)mmol/gFe2+升高到(3.03±0.0019)mmol/g Fe2+。[结论]烘焙小粒咖啡多糖是一类由半乳糖、鼠李糖、葡萄糖、阿拉伯糖和甘露糖组成的具有孔状结构的多糖。
[Objective]To study the composition and structural characteristics of polysaccharides from roasted beans of Coffea arabica.[Methods]Roasted beans of C.arabica were used as raw materials.The hot water extraction combined with alcohol precipitation method was optimized using the response surface methodology to extract polysaccharides.The crude polysaccharide was purified using the Sevag method,macroporous resin,cellulose column,and gel separation technology.Total sugar,total phenol,total flavonoid,and monosaccharide compositions were analyzed using the phenol-sulfuric acid method,Folin-Ciocalteu assay,NaNO_(2)-AlCl3-NaOH method,and ion chromatography,respectively.The structural characteristics of the polysaccharides were characterized by infrared spectroscopy(IR)and scanning electron microscopy(SEM).Additionally,the in vitro antioxidant activity of the polysaccharides was evaluated.[Results]The optimal extraction conditions for polysaccharides from roasted coffee beans were as follows:extraction temperature of 80.4℃,extraction time of 48 min,liquid-to-solid ratio of 15.3∶1(mL/g),and ethanol volume fraction of 75%.Under these conditions,the polysaccharide yield was(7.56±0.26)%.After purification,five polysaccharides(RBP1,RBP2,RBP3,RBP4,and RBP5)were obtained,which were primarily composed of galactose(Gal),rhamnose(Rha),glucose(Glc),arabinose(Ara),and mannose(Man).The infrared spectra of the polysaccharides showed characteristic absorption peaks near 3300~3500 cm^(-1),2900~3000 cm^(-1),1600 cm^(-1),1400~1300 cm^(-1),and 1000 cm^(-1).SEM images showed that the polysaccharides exhibited a series of compact,porous structures,with RBP4 displaying a dense and regular pore structure.The antioxidant activity results showed that RBP0 had the strongest antioxidant capacity,which increased with concentration in the range of 0.1~0.5 mg/mL.The DPPH radical scavenging ability increased from(1.53±0.32)%to(82.85±0.61)%,and the iron reduction ability(FRAP method)increased from(0.39±0.00048)mmol/g Fe2+to(3.03±0.0019)mmol/g Fe2+.[Conclusion]The polysaccharides from roasted beans of C.arabica are vesicular polysaccharides primarily composed of galactose,rhamnose,glucose,arabinose,and mannose.
作者
沈晓静
叶仁凤
龚姝淳
王洪圣
姜薇薇
SHEN Xiaojing;YE Renfeng;GONG Shuchun;WANG Hongsheng;JIANG Weiwei(College of Science,Yunnan Agricultural University,Kunming,Yunnan 650201,China)
出处
《食品与机械》
北大核心
2025年第4期63-71,共9页
Food and Machinery
基金
云南省科技计划项目农业联合专项面上项目(编号:202101BD070001-046)
云南省科技人才与平台计划项目—中青年学术和技术带头人后备人才项目(编号:202405AC350064)
云南特色植物提取实验室自主研究项目(编号:2022YKZY001)。
关键词
小粒咖啡
烘焙豆
多糖
提取
纯化
结构
抗氧化能力
Coffea arabica
roasted beans
polysaccharide
extraction
purification
structure
antioxidant capacity
