Study On The Extraction Technology Of Yeast Wall Polysaccharide And Yeast Self-solubility In A Solid State Fermentation

In this paper,the content of zymosan was determined at different inoculation respectively.After the inoculum was confirmed,the effects of several factors,including pH value of zymosan buffer,acid hydrolysis temperature and time,on the zymosan concentration were studied.At the same time,the temperature,time and zinc ion concentration were studied for yeast autolysis.The optimum working ranges of autolysis temperature,autolysis time and zinc ion concentration were determined by measuring the contents of free amino acid,soluble protein,?-amino nitrogen as well as A260/A280 in the solid fermentation material.Based on that,the L9(33)orthogonal test was set to optimize the process parameters of yeast autolysis under solid state conditions.(1)The content of ?-glucan in the 8%inoculation amount was significantly higher than that in the 15%group(P<0.05).Meanwhile,the content of mannan in the former group was also higher than that in the later one,although without significant difference(P>0.05).(2)The polysaccharide purification process was performed with pH 7.0 phosphate buffer,pretreated with 72%sulfuric acid for 1 h,and hydrolyzed at 120 ?for 90 min.Consequently,the contents of dextran and mannan were significantly increased(P<0.05),which were higher than those in the original process,by 20.71%and 8.6%respectively.(3)The optimal process condition for yeast autolysis was:autolysis temperature 55 0C,action time 18 h,and zinc ion concentration 2 mg/kg.At this condition,the soluble protein content could reach 9.31 mg/g,with the free amino acid 14.36 mg/g,the ?-amino nitrogen 10.16 ug/g and the A260/A280 1.73.