Study On The Separation, Purification And Elementary Structure Of The Polysaccharide From Chinese Yam

On the basis of systematic research of isolation, separation, purification, physics-chemical property, antioxidants and the elementary structure of the yam polysaccharide, which was academically and practicably important for opening out relationship between structure and bioactivity of yam polysaccharide, make full use of the Chinese yam resource. The main contents and conclusions are listed asfollows:1.By using traditional water isolation and alcohol precipitate to extract the yam polysaccharide, the orthogonal experiment about extraction time, temperature, liquid-solid ratio on the extraction yam polysaccharide showed that, the influence sequence on the isolation yam polysaccharide was as follows: temperature>solid-liquid ratio>time. The best isolation yam polysaccharide technology was solid-liquid ratio 1∶20 at 100℃temperature for 2.5 hours and isolation 2 times. The extraction ratio was 3.7% and reach 21.7%purity. It was enough to fit the isolation requirement at alcohol concentrate 80% for 2 hours.2. The purification experiment of yam polysaccharide showed that it was more better to scavenge protein using Sevage &enzyme hydrolysis method than simply using Sevage method, that means the most part of protein was scavenged by enzyme hydrolysis, just a little part of protein was moved by Sevage method. The minority polysaccharide loss was its advantage. The enzyme hydrolysis conditions were 1.5% neutral enzyme and Ph value 7.0, concentrate at 40℃for 2 hours. Small molecule substances were moved by dialysis bag for 48 hours dialysis which can withhold molecule 8000. Two kinds of yam polysaccharide was separated by 0~1M ion intensity gradient elusion, this 2 kinds of polysaccharide were neutral polysaccharide and acidity polysaccharide. The following Sephadex G-100 elusion result showed the neutral polysaccharide has a equally molecule, but the acidity polysaccharide didn't have equally molecule, another 2 kinds of different molecule acidity polysaccharide was separated, they were acidity polysaccharide 1 and acidity polysaccharide 2.The UV spectrum result show these 3 kinds of polysaccharide was not starch and without protein and optical rotation were +162.50,+480,-1280. This 3 kinds of polysaccharides also had different deradical power, the acidity polysaccharide 2 had the strongest ability, it would deradical ?OH ratio 50% at 30μg/ml concentrate.3. The structure-bioactivity relationship means the relationship between elementary structure and advanced structure with bioactivity. The recent research on the polysaccharide showed all of polysaccharide's bioactivity had close connection with its structure. The TLC analysis showed that glucose and mannose existed in neutral polysaccharide and the following GC-MS also confirmed this. Its Mol ratio was 0.56∶0.44, but the TLC hadn't effectively separated the glucose, mannose and fructose for GC-MS found they were glucose, mannose and galactose (0.54∶0.02∶0.44). Acidity polysaccharide 2 composed by Arabnose, xylose, glucose and mannose (0.07∶0.22∶0.7∶0.01). The IR spectrum showed that neutral polysaccharide and acidity polysaccharide 2 wereαtype heteromerous; acidity polysaccharide 1 wasβtype heteromerous.