仙人掌果多糖的结构表征、理化性质及抗氧化活性研究

发布时间：2018-06-15 00:44

本文选题：仙人掌果 + 多糖　；参考：《合肥工业大学》2017年硕士论文

【摘要】：本文以海南三亚野生仙人掌的果实为原料,提取得到的仙人掌果多糖为研究对象,对仙人掌果多糖的理化性质、初级与高级结构特征和体外抗氧化活性进行了探讨。首先采用水提醇沉法,从仙人掌果果肉的水提浓缩液60%乙醇沉淀物中得到粗多糖,粗多糖经过脱色脱蛋白后,再经过DEAE-52纤维素和Sephacryl S-400凝胶柱层析进一步分离纯化,最终获得一个均一的酸性多糖组分(OFPP)。通过HPGPC、UV、XRD、TG-DSC、SEM、Raman光谱仪、Zeta电位仪和流变仪等技术手段研究了多糖组分OFPP的理化性质,结果表明OFPP分子量约为1.98×106Da,多糖含量达到82.4%±0.95,糖醛酸含量34.29%±1.74,不含蛋白质和核酸,Zeta电位为-24 mV,呈现假塑性行为,是典型的非牛顿性流体。结果还表明OFPP表面形态为宽松的片状,呈现半结晶状,并且具有良好的热稳定性。其次通过GC、GC-MS、FT-IR、NMR、刚果红实验、圆二色谱、TEM和AFM等技术手段研究了OFPP的初级结构和高级结构。结果表明,其主要由鼠李糖(40.8%)、半乳糖(34.5%)、阿拉伯糖(14.4%)、葡萄糖(5.9%)、岩藻糖(1.8%)、木糖(1.6%)和甘露糖(1%)等组成。OFPP可能是一种类果胶多糖,推测的结构是主链由→2)-α-L-Rhap-(1→4)-α-D-GalpA-(1→组成,同时在α-L-Rhap的O-4位置被中性糖α-L-Araf、α-D-Galp和α-D-Glcp部分取代作为支链。OFPP在水溶液中缺乏三股螺旋构象,可能呈现球状构象。Ca~(2+)络合效应能强烈地改变多糖分子构象。TEM和AFM进一步证实了OFPP在水溶液中存在分子球状构象,并且单一分子直径约为26nm,高度约为5.9nm。本文还研究了仙人掌果多糖的体外抗氧化活性包括羟基自由基(·OH)清除能力、总还原力和金属Fe~(2+)离子螯合能力的测定。结果表明仙人掌果多糖具有一定的清除羟基自由基能力、还原力和金属Fe~(2+)离子螯合能力。
[Abstract]:In this paper, the fruit of wild cactus from Sanya of Hainan Province was used as the raw material, and the polysaccharides of cactus fruit were extracted as the research object. The physicochemical properties, primary and high structural characteristics and antioxidant activity of polysaccharides of cactus fruit in vitro were discussed. The crude polysaccharides were obtained from 60% ethanol precipitate of cactus pulp by water extraction and alcohol precipitation. The crude polysaccharides were further separated and purified by DEAE-52 cellulose and Sephacryl S-400 gel column chromatography after decolorization and deproteinization. Finally, a homogeneous acidic polysaccharide component, OFPP, was obtained. The physical and chemical properties of polysaccharide component OFPP were studied by means of HPGPC UVX XRDX TG-DSCT Raman spectrometer Zeta potentiometer and rheometer. The results showed that the molecular weight of OFPP was about 1.98 脳 10 6 DaA, the content of polysaccharide was 82.4% 卤0.95, the content of uronic acid was 34.29% 卤1.74, and the Zeta potential of OFPP was -24 MV without protein and nucleic acid, which showed pseudoplastic behavior and was a typical non-Newtonian fluid. The results also show that the surface morphology of OFPP is loose, semi-crystalline and has good thermal stability. Secondly, the primary and advanced structures of OFPP were studied by means of GCX GC-MSFT-IR, Congo red test, circular dichroism (CD) TEM and AFM. The results show that OFPP is mainly composed of rhamnose 40.8g, galactose 34.5m, arabinose 14.4m, glucose 5.9m, fucosaccharide 1.8g, xylose 1.6) and mannose 1). OFPP may be a kind of pectin polysaccharide, and the conjecture is that the main chain is composed of 2n- 伪 -L-Rhap-1, 4- 伪 -D-GalpA-1. At the same time, O-4 position of 伪 -L-Rhap was partially replaced by neutral sugar 伪 -L-Araf, 伪 -D-Galp and 伪 -D-Glcp as branched chain. OFPP lacked three helix conformation in aqueous solution. It is further confirmed that the conformation of OFPP is spherical in aqueous solution, and the diameter of single molecule is about 26nm and the height of OFPP is about 5.9nm. the complex effect of the complex can strongly change the conformation of polysaccharide molecule. Tem and AFM further confirm the existence of molecular spherical conformation in aqueous solution of OFPP, and the single molecular diameter is about 26nm and the height of OFPP is 5.9nm. The antioxidant activities of cactus polysaccharides in vitro, including the scavenging ability of hydroxyl radical (OHs), the total reduction capacity and the ion chelating ability of metal Fean2, were also studied. The results showed that the polysaccharides of cactus had the ability of scavenging hydroxyl radical, reducing ability and chelating ability of metal Feb2) ion.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ281

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