Extraction,Purification And Antiglycation Of Polysaccharides From Bamboo Shavings(Caulis Bamfusae In Taeniam)

Polysaccharides are a kind of important secondary metabolites in plants. Bamboo shavings, as the main lignocellulosic residues produced in bamboo processing industry, are outer epidermis of bamboo scraping process. They are often used as fuel or abandoned, so the economic benefit is low. And the polysaccharides of bamboo-shaving have not attracted the attentions of people.IN this study, steam explosion pretreatment has been applied in the preparation of bamboo-shaving polysaccharides (BSP) from Phyllostachys heterocycla var. pubescens, after purification, the chemical characterization, antiglycation and antioxidant activitis of BSP have been studied. The main contents and results are summarized as follows:1. Steam explosion pretreatment was applied in bamboo shavings. Hot water extraction and ethanol precipitation were employed to extract polysaccharides from steam-exploded bamboo shavings, which were further purified to obtain the refined BSP, and the physicochemical properties of BSP were analyzed. The extraction condition was optimized based on the yield of crude BSP as follows:solid-liquid ratio1:15(g/mL), extraction temperature100℃, extraction time2.5h. Part of the crude BSP were precipitated with ethanol to get purified polysaccharides, named as BSP-JZ, the content of BSP-JZ was80.75%, the yield of BSP-JZ was2.25%(dry basis), and the average molecular weight of BSP-JZ was7.67kDa; part of the crude BSP were precipitated with ethanol to get30%,60%and80%(final concentration of ethanol), named as BSP-30, BSP-60and BSP-80, the contents of each BSP were79.85%,83.05%and83.60%, the yields of each BSP were0.30%,0.93%and0.87%(dry basis), and the average molecular weight of each BSP were36.42kDa,11.04kDa and2.94kDa; the chemical composition analysis showed that these four kinds of BSP were mainly composed of polysaccharides, lignin, phenolic acids and protein, glucose and xylose were the main components of their monosaccharides, and their solutions were a kind of pseudoplastic fluid.2. Simulation system of protein non-enzymatic glycation was applied to research antiglycation acitivity of BSP. The results showed that, BSP samples showed different antiglycation acitivities, and BSP-30was the best. When the final concentration of BSP-30was0.7mg/mL, on the10th day, the inhibition rates of BSP-30for products from3stages of glycation (Amadori productâ†'carbonyl compoundsâ†'fluorescent AGEs) were57.33%,67.10%and75.01%, which were significantly higher than the commercially available AGEs inhibitors (Prime AGE)(15.01%,16.72%and20.02%); as for the inhibition of non-fluorescent AGEs (Carboxymethyl lysine, CML), the inhibition rate of BSP-30was63.80%, which was lower than Prime AGE (73.31%), as well as the positive control aminoguanidine (AG,91.50%). Inhibitory effects of BSP-30for CML produced by hot processing of food were related to concentration of sample, reaction time and reaction temperature, when the final concentration of BSP-30was5mg/mL, after reaction for8h at70℃, the inhibition rate of CML could be as high as90.03%, which was close to the effect of AG (99.99%), however, it was significantly higher than Prime AGE (26%) at the same conditions (p<0.01).3. Free radical scavenging abilities (·OH,·O2-, ABTS+and DPPH) and reduction ability of metal ions (ferric reducing abilities power, FRAP) in vitro were evaluated for antioxidant capacity of different BSP samples. The results showed that, BSP-30had relatively high scavenging activities for·OH,·O2-and DPPH·, which were higher than Prime AGE; as for ABTS+scavenging ability and FRAP, BSP-80showed the best effect, significantly better than Prime AGE.This study has showed that, after steam-explosion treatment, the dense structure of fiber from bamboo shavings was opened, which was beneficial to the extraction of water-soluble hemicellulose polysaccharides. After simple methods for separation and preparation, we could obtain BSP of high purity and high yield with excellent antiglycation activities, which means that BSP has great potential as natural inhibitors of AGEs.