Preparation Of Sparassis Crispa Low Molecular Weight Polysaccharide And Its Probiotic Effect In Vitro

Sparassis crispa is a kind of medicinal and edible bacterium rich in?-glucan.In recent years,a large number of studies have shown that Sparassis crispa polysaccharides?SCP?has excellent performance in anti-tumor and immune regulation.Although the anti-tumor effect of SCP has entered the clinical stage in Japan,so far,there are a few studies on other biological activities of SCP.In order to explore the probiotic effect of SCP and low molecular Sparassis crispa polysaccharides?SCLP?in vitro,the acidolysis process of SCP was optimized by response surface method,and the structure of SCP and SCLP was characterized.The proliferation of SCP and SCLP on Bifidobacterium longum,Bifidobacterium lactis and Lactobacillus paracasei was studied by anaerobic culture in vitro.The main results are as follows:?1?Study on the preparation of low molecular weight polysaccharide?SCLP?In order to explore the preparation process of SCLP the SCP was degraded by dilute sulfuric acid,the degree of polysaccharide hydrolysis was taken as an indicator,the sulfuric acid concentration,the reaction time,and the liquid-material ratio were taken as factors on the basis of single-factor experiment,the degradation surface preparation process was optimized by the response surface Box-Benhnken design.According to the analysis,the influence of the three factors on the response value is:reaction time>liquid-to-material ratio>sulfuric acid concentration.The optimal process conditions are:sulfuric acid concentration is 0.46 mol/L,reaction time is 85.5 min,and liquid-to-material ratio is 100:1 m L/g.Under this condition the degree of polysaccharide hydrolysis is 67.07%±0.77%.?2?Structural characterization for SCP and SCLPThe result of full-band scanning proved that SCP and SCLP are both polysaccharides and free of impurities such as proteins and others.It is inferred from the infrared spectrum that SCP is mainly composed of?-type glycosidic bonds and contains a large amount of six-carbon sugars,and is a typical?-glucan.SCLP is similar to SCP,but some hydrogen bond have been broken.In addition,the absorption peak of?-type glycosidic bond was not found in the infrared spectrum.According to the GC-MS test,the SCP monosaccharides was glucose,galactose,ribose and arabinose,and the SCLP monosaccharideswas glucose,galactose,ribose and mannose.From the measurement of SCP and SCLP by SEC-MALLS-RI technology,it is knownthat SCP contains three components,and the average molecular weight Mw is 3.32×10⁷?3?The probiotic effects of SCP and SCLP in vitroThrough in vitro culture,the OD₆₀₀ value,reducing sugar content,p H value and short-chain fatty acids?SCFAs?in the culture medium were used as evaluation indicators To comparethe proliferation effects of SCP and SCLP on Bifidobacterium longum,Bifidobacterium lactis and Lactobacillus paracasei.The results showed that SCP and SCLP have a proliferative effect on the three bacteria,and SCLP has a more obvious proliferation effect than SCP.From the OD₆₀₀ value and reducing sugar content,it can be seen that the three types of bacteria can use SCP and SCLP for reproduction and other life activities.The concentration of bacteria in the SCLP group is significantly higher than that of the SCP group?P<0.05?.With the increase of the concentration of probiotics,the p H value in the medium decreases accordingly,which indicated that SCP and SCLP could be metabolized by the three probiotics to produce organic acids.It can be inferred from SCFAs that two kinds of bifidobacteria produce acetic acid,Lactobacillus paracasei produces acetic acid and butyric acid,and the content of short-chain fatty acids produced by SCLP fermentation is higher than SCP.The above results indicate that SCLP is more easily to be used by probiotics than SCP.