超声-酶法提取的豆腐柴低酯果胶理化性质及结构表征  

Physicochemical properties and structure characterization of low-methoxy pectin from Premna microphylla Turcz extracted by ultrasound-enzyme treatment

作　　者：刘昕 张驰 薛艾莲 赵吉春 曾凯芳[1,2] 明建[1,2] LIU Xin;ZHANG Chi;XUE Ailian;ZHAO Jichun;ZENG Kaifang;MING Jian(College of Food Science,Southwest University,Chongqing 400715,China;Research Center of Food Storage&Logistics,Southwest University,Chongqing 400715,China)

机构地区：[1]西南大学食品科学学院,重庆400715 [2]西南大学食品贮藏与物流研究中心,重庆400715

出　　处：《食品与发酵工业》2021年第8期108-115,共8页Food and Fermentation Industries

基　　金：重庆市技术创新与应用发展专项面上项目(cstc2019jscx-msxmX0407)。

摘　　要：以豆腐柴为原料,采用超声-酶法提取低酯果胶,并探究其理化性质、结构特征、抗氧化活性以及流变特性。结果表明,超声-酶法提取的果胶得率达35.53%,相比传统酸法提取提高17.28%,属于低酯果胶(酯化度为16.80%),颜色呈现淡黄色,其总糖醛酸含量达到81.17%(质量分数)。通过高效液相色谱法对果胶分子质量进行测定,其重均分子质量(M w)为27.24 kDa,数均分子质量(M n)为15.30 kDa,M w/M n为1.78,表明豆腐柴果胶分子质量较低,且较为均一。单糖组成分析发现,半乳糖醛酸、葡萄糖、鼠李糖、半乳糖等是主要组分,其结构线性度较低,主要结构为短侧链的RG-Ⅰ型。红外光谱扫描特征峰证实其含有果胶成分;扫描电镜显示其表面粗糙,含有较多孔隙结构;X射线衍射表明豆腐柴果胶具有一定的结晶度;差示量热扫描、热重分析显示豆腐柴果胶在259.3℃发生降解,热稳定性较好;流变学分析结果表明不同浓度豆腐柴果胶溶液均出现剪切变稀现象,为非牛顿流体,10 g/L的果胶溶液储能模量(G′)高于损耗模量(G″),表现出较好的弹性;抗氧化活性测定显示豆腐柴果胶清除DPPH自由基、ABTS阳离子自由基的IC 50分别为0.37、0.34 g/L。研究结果为豆腐柴低酯果胶的开发及综合利用提供理论依据。The low-methoxy pectin was extracted from Premna microphylla Turcz with ultrasound-enzyme method.Its physicochemical properties,structural characteristics,antioxidant activity and rheological properties were explored.The results showed that the yield of pectin extracted by ultrasonic-enzyme method was 35.53%,which was 17.28%higher than that of the traditional acid extraction method.The pectin obtained belonged to low-ester pectin(the degree of esterification was 16.80%).The color of the pectin was pale yellow,and its galacturonic acid content was 81.17%.Molecular weight of the pectin was determined by HPLC.The weight average molecular weight(M w)was 27.24 kDa,the number average molecular weight(M n)was 15.30 kDa,and the M w/M n was 1.78,which indicated that the molecular weight of P.microphylla pectin was relatively low and uniform.D-Galacturonic acid,glucose,rhamnose and galactose were the main monosaccharide components of the pectin.Its structural linearity was low and its main structure was RG-I Type with short side chain,which were found through the analysis of monosaccharide composition.Characteristic peaks of Fourier transform infrared spectrometer confirmed that it contained pectin.SEM showed that the surface was rough and contained a lot of pore structure.X-ray diffraction analysis showed that the pectin had a certain degree of crystallinity.Differential scanning calorimetry and thermogravimetric analysis results showed that pectin had good thermal stability,and the pectin was degraded at 259.3℃.Rheological results showed that pectin extracted from P.microphylla presented non-Newtonian shear-thinning behavior.G′of 10 g/L pectin solution was higher than G″,showing better elasticity.IC 50 of DPPH and ABTS free radicals were 0.37 and 0.34 g/L respectively in the antioxidant activity test.This research results provide a theoretical basis for the development and comprehensive utilization of low-ester pectin from P.microphylla.

关 键 词：超声 酶 豆腐柴 果胶 结构 

分 类 号：TQ28[化学工程—有机化工]