【作者】 杨明峰；

【导师】 赵萍；

【作者基本信息】 兰州理工大学 ， 食品科学， 2010， 硕士

【摘要】 麦芽根是麦粒发芽后的须根,纤细而弯曲。麦芽根作为啤酒工业副产物约占大麦总投料的3%。麦芽根中含有氨基酸、蛋白质、碳水化合物、维生素和矿物质等多种元素和营养物质,目前,麦芽根在国内外主要作为饲料使用。本文以大麦麦芽根为原料,对其进行了基本营养成分分析,优化麦芽根多糖的提取工艺,并对其多糖进行分离纯化、纯度鉴定、理化性质、初级结构分析及生物活性等方面的研究。具体的研究内容及结果如下：采用水提醇沉法提取麦芽根水溶性多糖,在单因素实验的基础上,通过正交试验研究了提取温度、提取时间及液料比对麦芽根多糖提取率的影响,从而确定了麦芽根多糖的最佳提取工艺参数：液料比40：1(V/W)、温度90℃、浸提3次、时间2h。麦芽根水提取的粗多糖经脱蛋白、脱色、不同乙醇浓度沉淀后得到精制的麦芽根多糖BCP30、BCP50、BCP80。BCP80经过二乙氨基乙基(DEAE)纤维素柱层析,用0～1.0mol/L NaCl溶液洗脱,分别得到三个洗脱组分,浓缩、冷冻干燥后分别为白色粉末状的多糖BCPⅠ、BCPⅡ、BCPⅢ组分。BCPⅡ经Sephadex G-100柱层析得到两个对称峰BCPⅡa、BCPⅡb;BCPⅢ经Sephadex G-100层析分离得到一个组分为BCPⅢa。BCPⅡa、BCPⅡb和BCPⅢa经纸层析、醋酸纤维薄膜电泳和旋光法鉴定为均一组分。麦芽根多糖纯品BCPⅡa、BCPⅡb、BCPⅢa为白色粉末状固体,可溶于水、稀酸碱,不溶于乙醇、丙酮等有机溶剂。苯酚-硫酸反应呈阳性,斐林试剂反应呈阴性,考马斯亮蓝染色反应呈阴性,碘—碘化钾反应呈阴性,Molish反应呈阳性,三氯化铁反应呈阴性。实验表明三种多糖是非还原性、不含多酚、无蛋白的多糖。经UV、IR和1H-NMR分析可知,三种多糖为β-糖苷键连接的吡喃环多糖。采用水提旋蒸浓缩醇沉法提取并精制多糖,用50%和80%乙醇分段醇析分离得两种粗多糖BCP50和BCP80；用分光光度法研究了两种粗多糖在不同体系中对羟自由基、超氧自由基、DPPH自由基的清除作用、还原力以及用Rancimat油脂氧化仪测定其抗氧化活性。上述的研究结果表明,分离纯化得到的麦芽根多糖为β-糖苷键吡喃环多糖。从麦芽根中在优化工艺条件下提取的水溶性多糖,具有一定的抗氧化活性,另外,研究麦芽根多糖的抗氧化活性为研究其免疫活性与抗肿瘤、抗突变、抗病毒等的研究提供理论基础。更多还原

【Abstract】 Barley malt roots are fibrous roots of malt, slender and curved. Barley malt roots as a by-product of beer industry account for about 3% of total feed. Barley malt roots contain amino acids, proteins, carbohydrates, vitamins and minerals and other elements and nutrients. At present, Barley malt roots mainly used as feed all over the world. In this paper, barley malt roots as a raw material were systematic studied on the aspect of basic nutritional component, optimization of extraction of polysaccharides from malt roots, separation, purification, physical and chemical properties, primary structure and biological activity. The results are as follows:Method of water extraction and alcohol precipitation was used for extracting water-soluble polysaccharide from malt roots. Orthogonal experiment based on the single factor experiments which were extraction temperature, extraction time and ratio of solid to liquid, on extraction rate of polysaccharides of malt roots. The optimum extraction parameters:liquid ratio 40:1 (V/W), temperature 90℃,extraction three times, time 2 hours.The polysaccharides of malt roots BCP30, BCP50, BCP80were obtained by water extract, protein removal, decolorization, precipitation and refined with different concentration of ethanol. BCP80 was obtained after diethylamino ethyl (DEAE) cellulose column chromatography. Using 0 to 1.0 mol/L NaCl solution, elution, three fractions BCPⅠ,BCPⅡ,BCPⅢwere obtained. The three fractions were concentrated and freeze-dried, white powder were obtained. BCPⅡpurified by Sephadex G-100 column chromatography was obtained two symmetrical peaks BCPⅡa, BCPⅡb. BCPⅢpurified by Sephadex G-100 column chromatography was obtained a fraction named as BCPⅢa. By paper chromatography, cellulose acetate membrane electrophoresis and optical rotation, BCPⅡa, BCPⅡb and BCPⅢa were homogeneous fractions, respectively.BCPⅡa, BCPⅡb, BCPⅢa are white powdery solid, soluble in water, dilute acid and alkali, insoluble in ethanol, acetone and other organic solvents. Phenol-sulfuric acid reaction was positive, negative Fehling reagent, Coomassie brilliant blue staining reaction was negative, iodine-potassium iodide reaction was negative, Molish positive for reaction, ferric chloride reaction was negative. Results show that the three fractions of polysaccharide are of non-reducing, non-polyphenol, protein-free polysaccharide. UV, IR and 1H-NMR analysis, the three fractions of polysaccharide areβ-glycosidic linkage of the pyran ring polysaccharide. Rotary steam condensed by water extraction and alcohol precipitation of polysaccharide extracted and purified with 50% and 80% ethanol were two separate sub-analysis of alcohol polysaccharides BCP50 and BCP80,Spectrophotometry of the two polysaccharides in different systems on the hydroxyl radical, superoxide, DPPH radical scavenging, reducing power and lipid oxidation determined with the methord of Rancimat with witch antioxidant activity were measured.The results show that the polysaccharides separated and purified from malt roots are beta glycosidic bond pyranoid ring polysaccharide. There exists antioxidant activity for malt extract extracted at optimization being water-soluble polysaccharide. And more, malt polysaccharide antioxidant activity offers the base for further studies of immune activity, antitumour, antimutation, antiviral. Therefore, the research on active, polysaccharides especially malt plays an important role and broad application prospect.更多还原