Corncob The Xos Extract Qualitative And Quantitative Analysis

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.