玉米芯中低聚木糖提取和定性定量分析

【作者】 张静文；

【导师】 张凤清；

【作者基本信息】 长春工业大学 ， 食品科学， 2010， 硕士

【摘要】 功能性食品的研究与开发给食品工业注入了全新的内容,而生产功能性食品的关键是功能性食品基料即生理活性物质的制备。功能性低聚糖因具有独特的生理功能,特别是能促进肠道内双歧杆菌的增殖,有益于肠道健康而成为一种重要的功能性食品基料,已引起世界的广泛关注。低聚木糖是D-木糖单元通过β-1,4-糖苷键组成的低聚糖,以木二糖和木三糖为主,极难被消化吸收,肠道内残存率高,具有极好的双歧杆菌增殖性,其选择利用性高于其它功能性低聚糖。玉米是我国三大粮食作物之一,每年玉米芯产量极其可观,目前除少量进行初加工外,绝大部分作为农家燃料被烧掉,即浪费资源又污染环境。因此,开展以玉米芯为原料,低聚木糖生产方面的理论和生产技术的研究是十分必要的。从2007年开始,课题组成员依托吉林省教育厅基金资助项目(2007第415号)“玉米芯中低聚木糖提取和定性定量分析”,开展玉米芯中低聚木糖的研究工作,其中提取和定性定量研究是课题研究的重要内容,本论文就是在此背景下开展的。目前,对其低聚木糖的主要组分的检测研究已经完成。本课题的主要目的是设计并优化提取纯化工艺路线,并对其组分进行定性定量研究。主要研究工作包括：1、简要介绍了低聚木糖的研究意义、发展历史及其研究现状。2、玉米芯总糖提取纯化工艺研究。采用热水浸提法对玉米芯总糖的提取工艺路线进行了试验分析,在结合效能考虑后确定最优工艺路线：浸提温度90℃、料液比1：25(g/mL)、浸提时间2.5h、一次浸提、80%醇沉操作,此条件下的提取率为13.18%。采用冻融分级除杂、Sevage法除蛋白、活性炭脱色对玉米芯总糖进行纯化试验研究。通过单因素试验确定的活性炭脱色条件为：温度70℃、活性炭用量4%、脱色时间60min,活性炭对糖液的脱色率为78.04%,糖损失率为16.61%。紫外光谱结果显示纯化后的玉米芯总糖无核酸和蛋白质。3、玉米芯低聚木糖的制备研究。采用SephadexG-25柱层析对低聚木糖进行制备,玉米芯总糖和部分酸水解糖样经柱层析操作后分别得到低聚木糖组分A和组分B。柱层析条件：洗脱液：0.1mol/L NaCl溶液；上样浓度：4%；上样体积：柱体积=1：35；洗脱液流速：0.17倍柱体积/h。糖液经阴阳离子交换树脂脱盐处理后,有效降低了糖液中盐含量,脱盐率为61.33%。4、玉米芯中低聚木糖定性定量分析研究。组分A和组分B的HPLC图谱显示,组分A主要为木二糖,含有少量木三糖,木二糖纯度可达91.27%,收率为3.91%；组分B主要为木二糖,纯度可达95.62%,收率为6.84%；可能含有少量木三糖,纯度较低,收率仅为0.22%。由组分B的MS图谱分析可知含有木二糖、木三糖、木四糖和木五糖。更多还原

【Abstract】 The research and the exploitation of functional foods have been poured a new content into the food industry. The key about processing functional foods is the preparation of functional foods’base materials. The functional oligosaccharides have many specific physiological functions, such as promoting the multiplication of Bifidobacteria in intestines, keeping good for people’s health, and have been paid close attention to all over the world. Xylooligosaccharides are oligosaccharides, composed of xylose units linked by (3-1,4-xylosidete bonds. Xylobiose and xylotriose are the major component.It’s very difficult to digest, and can keep a good multiplication for Bifidobacteria. The utilization of it is higher than other oligosaccharides. A maize is one of the three main foodstuff plants in China. The average yield of it is very large every year. Most of the corncobs are burnt. It’s very important to do theoretic researches and processing technologies about the xylooligosaccharides with corncobs.From 2007, all the members of the project group support the project of the Department of Education of Jilin province (20070415),which called investigation of xylooligosaccharides in corncob. This paper is started in this context. At present, the detection and investigation of the major components have been developed successfully.The purpose of this project is to design and optimize the extraction and purification processing and investigate component and content of xylooligosaccharides.The main development works are:1. The investigation significance, the development history and the investigation status of xylooligosaccharides are briefly introduced2. Investigations of extraction and purification of polysaccharides in corncob. Considering the efficiency and energy consumption, the optimum conditions for extraction of polysaccharides from corncob was obtained. The ratio of solid-liquid was 1:25(g/mL), temperature was 90℃, extraction time was 2.5h, one time, and precipitated with ethanol at the concentration of 80%. The method of freezing and thawing removing impurity, the method of Sevage removing protein and activated carbon removing pigment were used in the purification of polysaccharides in corncob. The optimum condition for decoloration with activated carbon was 80℃,30min treatment and 3% carbon dosage,. Under this condition, 78.04%of the pigment was removed and 16.61%of the polysaccharides were lost. There were no nucleic acid and protein in polysaccharides from corncob.3. Preparation of xylooligosaccharides in corncob. The polysaccharides and their hydrolysates were separately purified by Sephadex G-25 chromatography to be fractions A and B. The chromatography conditions were as follow:eluant:0.1mol/L NaCl; sample concentration:4%; sample volume:column volume=1:35; flow rate of eluent:0.17 times the column volume per hour. After treated with ion exchange resin D-301 and 732,61.45% salt was removed from the polysaccharides.4. Qualitative and quantitative investigation of xylooligosaccharides. The HPLC of fraction A showed that xylobiose were the major components, the purity of xylobiose was 91.27%, the yield of it was 3.91%, and the content of xylotriose was very low. The HPLC of fraction B showed that xylobiose and xylotriose were the major components, the purity of xylobiose was 95.63%, the yield of it was 6.84%, and the content of xylotriose was only 0.22%. The MS of fraction B showed that xylobiose, xylotriose, xylotetraose, xylopentaose.更多还原