Studies On The Extraction Conditions And Properties Of Polysaccharides Of Wild Auricularia Auricular

The nutrition, including protein, fat, total sugar, water, ash, crude fiber, VC, VB₁, VB₂, Fe, Se, Ca, Zn and polysaccharide of the wild and log-cultivated Auricularia auricula (Hook.) Underw (WAAU) from Dabie Mountain in Anhui were tested and compared, respectively. Both the traditional method and the microwave-assisting method were used to extract polysaccharide and the quality was studied. The extracted polysaccharide was separated and purified. The ingredients of single sugar were also analyzed. And the effects of WAAU polysaccharide on the hyperlipemia mice to decrease lipid level were studied. The main results obtained are as follows.1 These contents of protein, fat, total sugar and polysaccharide in the WAAU are respectively 0.7%, 0.066%, 1.4% and 2.96% more than those of log-cultivated ones. The contents of water, ash, and crude fiber are respectively 0.26%, 0.85% and 1.19% less than those in log-cultivated A. auricula. According to the SAS analysis, the differences in the contents of protein, fat, total sugar and polysaccharide are not significant. The difference in water content is significant, and those in ash and crude fiber contents are extremely significant. The contents of VC, VB1,VB2 of the WAAU are respectively 6.8 mg/100g, 0.17 mg/100g, and 0.052 mg/100g more than those in log-cultivated A. auricula., but the contents of Fe, Se, Ca and Zn of the WAAU are respectively 0.13 mg/100g, 0.005 mg/g, 118.59 mg/kg, and 2.58 mg/kg less than those in log-cultivated A. auricula. According to the SAS analysis, the differences in contents are all significant except Fe.2 The hot water extraction and alcohol deposit method were used to extract the polysaccharides from WAAU, and the conditions of extraction and physical-chemical properties were studied. The effects of four factors such as the proportion of water volume, the temperature of extraction, the time of extraction, the number of extraction on the extraction of polysaccharides were investigated. With the orthogonal design of L₉(3⁴), the optimum technological conditions for the extraction of polysaccharides from WAAU were obtained as follows: add 40 times water as much as WAAU at 85℃for 2 hours and extract for 2 times. The results of physical -chemical properties showed that there were polypeptide and AA in polysaccharides. Therefore, these polysaccharides are protein compound polysaccharides.3 The technology of microwave-assisted extraction was used to extract polysaccharides from WAAU. Based on traditional methods, an improved technology was used single factor and orthogonal experiments were used to determine the optimal technologic condition. The result showed that the optimum extraction condition was as follows: microwave power at 560w, 35s of the microwave extraction, material and liquid in the proportion 1:40, 3h of extraction time, and the extraction ratio of polysaccharides at 98.55%. Compared to the traditional extraction methods, the method of microwave-assisted extraction reduced the extraction time from 24h to 30s+3h and the extraction ratio was 7.12%. The advantages of microwave extraction technique over traditional extraction method were that it takes shorter time, consumes low energy and has high extraction ratio.4 The optimum procedure of WAAU with two advanced methods (chloroform-n-butyl alcohol and thicloroacetic acid-n-butyl alcohol) by L₉(3⁴) orthogonal experiment design was studied. The differences of the yield of composed polysaccharide from two methods were compared in this paper. The results showed that the method of using Thicloroacetic acid-n-Butyl alcohol has a higher percentage of removed protein, which is 70.69%, but a lower percentage of composed polysaccharide, which is only 67.87% .The method of Chloroform-n-Butyl alcohol has a lower percentage of removed protein and a higher percentage of compose polysaccharide, which are 51.39% and 80.31% respectively. The results of decolourization with activated charcoal were 6% of decolourization, temperature at 40℃,decolourization time of 20min. The result of decolourization with H₂O₂ was 20% of H₂O₂. The difference of decolourization effect between two methods was not remarkable. But the difference of the rate of polysaccharide was remarkable. Therefore, H₂O₂ is the best decolourization material. The polysaccharide, which had been removed from protein and colour, become purified polysaccharide by dialysis method and freeze-drying. The components of the polysaccharide were determined by applying PC (paper chromatograghy). The water solution of polysaccharide, which was made by purify polysaccharide through acid hydrolysis, was as the raw material. The result showed that WAAU polysaccharide was mainly composed of galactoe and xylose. The amounts of Rf were 0.36 and 0.44 respectively.5 The effects of WAAU polysaccharide on the hyperlipemia mice to decrease lipid level were investigated. According to weight and serum general cholesterol levels, 70 of the tested hyperlipemia male Kunming mice induced by high lipid diet were divided into 7 groups. And six groups of the experimental mice were poured with different dosages (1%, 3%, 5%, 8%, 12%, 20%) of WAAU polysaccharide through stomach respectively for 5 weeks. Every day they were poured with 1mL once. In the contrast group of mice, distilled water was used instead of WAAU polysaccharide. Then each group of mice was fed with high lipid fodder and observed the changes of weight and feed gain and analysis the effect of decrease mice blood lipid ( analysis TC,TG and HDL-C), which compared with high lipid diet group each week. Result indicated the levels of serum TC and TG were lower compared with CK group (P<0.05). The level of HDL-C was higher compared to CK group (P<0.05). The effect of WAAU polysaccharide, which addition was above 5%, was obvious on depressing blood lipid level.