| Pholiota nameko is a kind of edible and medicinal fungi, with aliases pearl mushrooms,which belongs to Basidiomycetes. Because of its rich nutrition and unique favor, Pholiota nameko has been gradually accepted and the market demand of it is increasing. But compare with other edible fungi, it was still at the stage of initial. Although the nutrition ingredient has been reported before, they were lack of deep research, the nutrition characteristics of different flushes were not explored. And the research emphasis of Pholiota nameko focuses on the extraction technology and activities of its crude extractions. Therefore, the products of Pholiota nameko now are primary processed only, such as fresh, dried and salted products, which is lack of market competitiveness. So the objectives of this topic are to measure and compare the differences nutrition ingredient of Pholiota nameko with national standards and conventional methods, which is from Hebei Pingquan. And then the topic goes on to the polysaccharides from Pholiota nameko. The extract technology was optimized and the polysaccharides was purified by chromatography. HPLC, HPGPC and other methods were used to measure their chemical structure and antioxidant activity. The main results are as follows.According to the nutrition analysis of Zaofeng 112 and C3, conclusions can be drew that the Pholiota nameko in first and second flush had a high value of nutrient. The Pholiota nameko of first flush had higher contents of total sugar, polysaccharide, fat, EAA/TAA, Ca, Fe, Cu, etc. And the contents of crude ash, protein, total amino acid and K in second flushes were higher than others. Meanwhile, the heavy metal contents of the first flush were the highest. But all heavy metal contents are all lower than relative standards. Based on the above results the best sample can be choice according to different test targets. Samples of the first flush can be choice to study its carbohydrate and polysaccharide. Samples of the second flush can be choice to study its protein and amino acid. Samples of the second flush can be choice to study its heavy metal and its migrate.Ultrasonic assisted extraction technology of polysaccharide was investigated. Single factor and orthogonal test were used to optimize the optimum extraction technology of Pholiota nameko polysaccharide. As a result, the optimal extraction conditions were: extraction time 6h and the ratio of water to raw material of 20:1, ultrasonic power of 500 W, where the highest yield of polysaccharide(3.10%) was obtained. PNP was obtained after polysaccharide extracted from Pholiota nameko in the optimum conditions, with deproteinized, ethanol precipitation and dialysis. PNP was purified by DEAE-Sepharose Fast Flow column chromatography and get two components, named PNP-1 and PNP-2, respectively. Neutral polysaccharide was named PNP-1 and the yield was 8.48%. Acidic polysaccharide was named PNP-2 and the yield was 41.20%. Through gel permeation chromatography and Sephadex G-100 analysis, two factions were identified as homogeneous component.According to the analysis of GPC, the molecular weights of two factions were gotten that PNP-1was 17513.42 Da and PNP-2 was 16202.91 Da. The monosaccharide composition of three polysaccharides was analyzed by precolumn derivatization HPLC. Galactose was the predominant monosaccharide of these three factions. But the ratios of each monosaccharide were different. PNP was contained by Man, Glu, Gal and Xyl with the ratios was 24.01%:21.29%:40.47%:14.23%. PNP-1 was contained by Man, Glu and Gal with the ratios was 22.18%:4.75%:73.07%. PNP-2 was contained by Man, Glu, Gal and Xyl with the ratios was 6.90%:22.81%:56.28%:14.01%. To study antioxidant activity via lipid peroxidation and superoxide anion, the results indicated that three factions all had a good ability of antioxidant activity. The ability of PNP-2 was higher than the other factions obviously. And the antioxidant activity of polysaccharide after purified was better than crude polysaccharide. |
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