【作者】 毕洁；

【导师】 王淼；

【作者基本信息】 江南大学 ， 食品科学， 2006， 硕士

【摘要】 乳酸菌胞外多糖已成为近年来食品科学研究的焦点之一。开菲尔多糖(Kefiran)属于乳酸菌胞外多糖,其具有多种重要的生理功能,在临床医药、食品工业、化学工业等都有着广泛的用途。本文对乳酸菌Lactobacillus kefiranofaciens发酵产Kefiran的发酵培养条件进行了研究,并对发酵生产获得的Kefiran的分离纯化方法及其组成、结构性质进行了研究。主要研究内容如下:1.对实验菌株Lactobacillus kefiranofaciens的起始发酵特性进行了研究,确定了接种量和初始种龄及发酵时间,并观察了菌体形态在发酵过程中的变化。2.通过单因素试验及正交试验优化了发酵培养环境,结果表明,培养温度和发酵过程中pH的控制对发酵过程中菌体的生长及产糖情况有较大影响,当采用CaCO3控制pH、恒温25℃培养时,Kefiran产量可达1.96g/L。3.优化了培养基的组成,利用工业原料麦芽汁和国产酵母粉进行发酵,可使菌体胞外多糖的产量达2.5g/L;采用SAS数据处理软件设计实验,对培养基中无机盐和微量元素的用量进行了优化,Kefiran产量进一步提高到2.6g/L。4.在多糖的分离纯化过程中比较了几种脱蛋白的方法,采用碱性蛋白酶与Sevage试剂相结合的方法能较好的除去粗多糖中的杂蛋白。5.采用高效凝胶过滤色谱(HPGFC)、高压液相色谱(HPLC)及红外光谱对Kefiran的分子量、分子组成等性质进行了研究;比较了在不同培养基(MRSL和优化后的麦芽汁培养基)中得到的两种Kefiran的结构性质。分析结果表明,培养基的组成不同,发酵所得多糖的分子量、单糖组成以及多糖的构型有较大差异。采用乌式粘度计对多糖Kefiran的流变学性质进行了研究,根据比浓粘度与相应浓度的关系图推算得到特性粘度[η]为73.86[100mL/g]。更多还原

【Abstract】 Exopolysacchaeid(EPS) of Lactobacillus has become one of focused researches recently. Kefiran is one kind of Lactobacillus EPSs, it has many important physiological functions, and is widely used in many fields, i.e. clinical medicine, food industry, chemical industry and so onIn this paper, the fermention conditions of Lactobacillus kefiranofaciens to produce Kefiran.were studied, Kefiran was separated and purified The composition, structure and characteristics of Kefiran were investigated.The main contents of this dissertation were as follows:1. The initial fermented characteristics of L.kefiranofaciens were studied. The inoculation ratio, initial seed age and the fermentation time were confirmed. The morphologe of the cell was observed in the process of the fermentation.2. The fermentation conditions were optimized by single factor experiment and orthogonal design. The results show that the temperature of culture and pH to be controlled during the fermentation process made a remarkable effect on growth of cell and production of EPS. When adopted CaCO3 to control pH and cultured at constant temperature 25℃, the yield of Kefiran could reach to 1.96g/L3. The composition of culture medium was optimized and the yield of EPS could arrive at 2.5g/L when malt juice and domestic yeast powder as the industrial raw materials were used during the fermentation process. The Kefiran yield further raised to 2.6g/L after dosage of mineral and trace element were optimized by Response Surface Analysis.4. Several methods to remove of protein from crude Kefiran were studied. The results showed that the alcalase treatement combined with Sevage reagent method was better.5. HPGFC, HPLC and IR were used to research on properties of Kefiran. Structures and properties of two kind of Kefiran produced from two different culture mediums (MRSL and malt juice) were contrasted, and the result indicated that if ingredients of culture mediums were different, properties and configuration of polysaccharides obtained after fermentation also presented quite difference. Rheology property of Kefiran was investigated and [η] was 73.86[100mL/g].更多还原