| Walnut is an important economic tree species in China.The planting area and gross product is the first in the world.With the improvement of living standard,people’s demand for walnut increased year by year,which produced many husk. Only few husk was used medicinal,most of husk were discard, which had caused very seriously pollution to the environment.To fully use walnut husk,this paper taked the‘Zanmei, Qingcui,Jinlong 1, Zhenzhuxiang,Lvbo,Yihe 1’at different periods as the raw materials,which studied on polysaccharide content,extraction technology,isolation structural analysis and antioxidative activity of polysaccharide from walnut husk.The main results were as follows:1. The polysaccharide content in six varieties of walnut was different,even though the same variety at different periods was different.By comparing polysaccharide content of different varieties,The polysaccharide content of‘Qingcui’at the fruit rapid growth period was the highest;‘Zhenzhuxiang’at the walnut shell sclerosis period was the highest;‘Jinlong 1’at the mature period was the highest.2. By comparing different periods showed that,the polysaccharide content of walnut shell sclerosis period was the highest and the next was the fruit rapid growth period and the mature period growth period.The content of polysaccharide of‘Yihe 1’was the lowest.3. The paper studied extraction technology of walnut husk polysaccharide,single factor test and orthogonal experiment design method were applied.The optimum conditions of extracting were obtained as follows extraction times is 3,extraction temperature is 95℃,the ratio of material to solvent was 1:25 and extraction time is 4 hour.By variance analysis,temperature and solid-liquid ratio were the significant factor.By the anthrone sulfuric acid method,the extraction yield of polysaccharides from walnut peel could be reached 4.523% under the optimum process.4. The different methods of removing protein sevag and trichloroacetic acid method were investigated,the latter destroyed polysaccharide structure,so sevag was used in this experiment,repeated five times,polysaccharide lost 15.73%;Polysacc- haride was soluble in water and insoluable in chloroform,ether and acetone,which did not contain starch and reducing sugar.5. Through studied on the polysaccharide function group of‘Zanmei’at three periods by infrared spectroscopy,all of them had characteristic absorption peak,three periods were all existed aldehyde group and alcoholic hydroxyl,Among them,polysa- ccharide configuration wasβ-conformation.6. Through differential scanning calorimetry(DSC),there was difference among the caramel reaction temperature of three periods.In contrast,polysaccharide of the fruit rapid growth period nearly closed to the mature period,in contrast,polysaccharide of the walnut shell sclerosis period had more diversity.7. The study found that the polysaccharide of walnut peel had reduction ability and antioxidant activity.It can effectively eliminate hydroxyl radical,superoxide anion and free radical of DPPH.As the polysaccharide concentration increased,the polysaccharide of walnut peel antioxidant activity enhanced,but the antioxidant capacity was weaked than Vc. |
