The Preparation Of Yeast Glucan

In this paper,the high-pressure-alkali extraction technology was put forward on the basis of the two extraction technologies for yeast glucan,and the investigations were carried out on the optimum of the extraction conditions,the character of the extractive. Then the preparation technology of yeast soluble glucan was optimized,which hydrolyzed by methyl acid,and the pilot study was carried through on the biology activity of yeast soluble glucan.The yeast glucan was extracted by three different technologies:alkali method, high-pressure method and the high-pressure-alkali method,and the yield,protein content, polysaccharide content,lipid content,ash content of the three extractions was determined. The results showed:the high-pressure-alkali method was the better method for the protein removing,and its extraction's polysaccharide content was high too.The effects of the dehydrated ethanol desiccation method,the acetone desiccation method and the vacuum freeze-drying method on the extraction were studied.The result was:the acetone desiccation method was the best way.The method for determination of yeast glucan content was investigated.The influence of different acid hydrolysis on result of determination was compared when Yeast insoluble glucan was hydrolyzed by H₂SO₄ and TFA in different hydrolysis conditions.The results showed that H₂SO₄ was more suitable than TFA as hydrolysis acid and the best hydrolysis conditions for Yeast insoluble glucan were obtained:2.7mol/L H₂SO₄,100℃,3h.The high-pressure-alkali extraction technology was optimized by orthogonal design. The result was that:alkali concentration 6%,pressure 0.1MPa and time 30min.The yield of yeast glucan was 23.30%and the polysaccharide content of the extraction was91.85%.The analysis results by IR and PC(Paper chromatography) showed the extraction only consisting glucose,and the extraction containingβ-glucoside.The application of Yeast glucan in the pharmaceutical industry was restricted by its water insoluble nature,so the yeast soluble glucan was prepared by methyl acid hydrolyzing,and hydrolysis conditions was optimized by orthogonal design.The optimum conditions were:the hydrolysis temperature 80℃,time 1.5h,the addition of methyl acid 1:10 and the concentration of methyl acid 90%.The yield of yeast soluble glucan was 80.15%,the analysis results by IR showed that:the structure of the product was not changed after hydrolyzing by methyl acid.The antimicrobial effect of the yeast soluble glucan against various microbe was studied.The results showed that the yeast soluble glucan could effectively inhibit the growth of bacteria,yet to mould and yeast,there was no effect.The minimum inhibitory concentration(MIC) of different bacterias were:Escherichia.Coli 75mg/mL,Salmonella gallinarum 37.5mg/mL,Bacillus subtilus 37.5mg/mL,Staphalococcus aureus 37.5mg/mL, and the pH range of inhibiting bacteria was 6.0～7.0.Moreover,the heat stability is good.