The Studies Of Extraction Of Lentinan And Application Of B-Glucosidase

Polysaccharides in the lentinusedode have anti-cancer, anti-tumor and other biological activities. Theβ-glucosidase has widespread application in the food processing and production. In this study, taking lentinusedodes as the raw material. The extraction ofβ-glucosidase and the enzymatic hydrolysis of soybean isoflavones and soybean residue had been explored in this experiment. Some polysaccharides remained in the residue of lentinusedodes. The extraction of polysaccharides from lentinusedodes were studied, mainly the hot water extraction, ultrasonic extraction, microwave extraction and subcritical water extraction. The protein was removed by the Sevag method after alcohol precipitation. Finally, the antioxidant activity of polysaccharides was determined.Using 3.5-dinitrosalicylic acid method for the content of reducing sugar, and phenol-sulfuric acid solution for the content of total sugar, the content of polysaccharide was obtained. The phenol-sulfuric acid method was further studied in the test, and the results showd that the method had good stability and reproducibility. The best wavelength for the determination was 490nm and the best dilution multiple was 200 times.The best conditions for the hot water extraction were determined through the single factor and orthogonal tests, namely the extraction temperature 100℃, liquid to solid ratio 40 mL/g, extraction time 3 h. Using ultrasonic extraction, the optimum conditions were as follows: extraction temperature 70℃, extraction time 45 min, liquid to solid ratio 30 mL/g, ultrasonic power 80 W. The best micro-wave extraction conditions: extraction temperature 90℃, microwave extraction time 10min, liquid to solid ratio 25 mL/g, microwave power 800 W. Using subcritical water extraction, the best conditions were as follows: sub-critical water temperature of 150℃, liquid to solid ratio 30 mL/g, extraction time 5 min. The extraction times of the above four methods were all 2 times.The yield of the four extraction methods under the best conditions were as follows: hot water extraction 4.90%, ultrasonic extraction 5.17%, microwave extraction 4.83%, sub-critical water extraction 7.63%; extraction time were: 3 h, 45 min, 10 min, 5 min; liquid to solid ratio were 40 mL/g, 30 mL/g, 25 mL/g, 30 mL/g; extraction temperature were 100℃, 70℃, 90℃, 150℃respectively. The above data showed that the time-consuming by hot water extraction was the longest, the liquid to solid ratio was relatively large, and the temperature was also very high. Regard to the traditional hot water extraction, the ultrasonic extraction was much shorter, with lower liquid to solid ratio and the minimum temperature requirements. Microwave extraction time was opposite reduced and the liquid to solid ratio and temperature is relatively smaller, but the rate of lentinan was slightly decreased compared with the above two methods. The rate of subcritical water extraction was the highest. The extraction completed instantaneously. In the actual production process, the appropriate extraction method must be choosed according to the actual situation.The best analysis of the final concentration of ethanol alcohol which was selected by alcohol precipitation test was 80%. Factors and the levels of the orthogonal test was used to study the methods of Sevag removing protein. By Sevag method lentinan extract the optimal conditions for removing protein were: oscillation time 2 min, still time 20min, sample liquid and Sevag reagent volume ratio 2:1, chloroform and butanol volume ratio 3:1. Polysaccharide samples were purified by Sevag methods for four times, 92.26% purity was obtained.Soybean residue was hydrolysed withβ-glucosidase from lentinusedodes were studied. When fresh soybean residue was hydrolysed, the soluble polysaccharide content was increased from 0.21 g/L to 0.27 g/L, and the soybean residue dried at 55℃was hydrolysed, the soluble polysaccharide content was increased from 0.80 g/L to 1.24 g/L, while soybean residue dried at 90℃was hydrolysed, the soluble polysaccharide content was increased from 0.52 g/L to 0.78 g/L. An amplification experiment was studied: 100 g soybean residue dried at 55℃was used, the Extracting solution of polysaccharide which hydrolysed withβ-glucosidase was determined, the content of soluble polysaccharide was increased from 0.82 g/L to 1.26 g/L, the soluble polysaccharide content had higher change.The experiment studied the hydrolysis of soy isoflavones by lentinanβ-glucosidase.After the hydrolysis of soy isoflavones , the results indicated that: the hydrolysis products was 1.6 g , the hydrolysis rate of daidzein and genistin were 98.15% and 94.23%。The study of lentinan polysaccharide's antioxidant activity showed that lentinan polysaccharide had strong antioxidant activity , and was approximate to Vc's antioxidant activity. Lentinan polysaccharide can effectively eliminate DPPH free radicals, the clearance rate was 55.0%; it can also eliminate hydroxyl radical, and the clearance rate was 76.5%.