Study On Extraction Process Optimization And Function Of Polysaccharides From Ta-Pieh Mountains’ Edible-Medicinal Fungi Grifola Frondosa

Grifola frondosa is a kind of rare fugus with homology of medicine and food.As a chestnut producing area,Ta-pieh Mountains has rich wild Grifola frondosa germplasm resources,as well as resource advantages and environmental climate advantages suitable for large-scale Grifola frondosa cultivation.At present,the selection of dominant strains of Grifola frondosa is limited.In this thesis,Grifola frondosa was selected as the research object,and the suitable varieties of Grifola frondosa in Ta-pieh Mountains were screened out.The effects of different light qualities on the growth of Grifola frondosa in the cultivation process were explored,and the cultivation conditions of Grifola frondosa were further optimized.To explore the best extraction process of the main active ingredient of Grifola frondosa polysaccharide and its biological function was studied.The experimental results are as follows.1.Sequencing and species identification of Grifola frondosa strains.Three strains of Grifola frondosa: JD01,JD02 and JD03,obtained by wild domestication in the Ta-pieh Mountains were activated.By observing the growth state of Grifola frondosa on solid medium,the mycelial growth rate was determined,and the dominant strains were determined.ITS-PCR technology was used to sequence and identify the species.The results showed that the three strains were all belonged to the Grifola.sp,and the similarity sequence between JD01 and strain Grifola frondosa GU203515.1 was as high as 99.83 %.Combined with morphological observation,it was named Grifola frondosa.sp JD01.The mycelium was white and dense,and the fastest growth rate was up to 3.59mm/d.JD01 was selected as the strain for cultivation experiment.2.The JD01 strain was selected for cultivation experiments to optimize the growth conditions of Grifola frondosa.LED light sources with different wavelengths were introduced during the cultivation process and the LED light source was regularly irradiated for 8 h/d.The natural light and dark state were used as controls to observe the growth state of fruiting bodies and explore the effect of light sources on the growth of Grifola frondosa.The results showed that the fruiting bodies could grow normally under red,yellow,blue,green,purple,white light sources and natural light,but did not mature in dark.Under the irradiation of blue and purple light sources,the time required for the emergence of Grifola frondosa primordium is the shortest,and the darkness is the longest;the diameter of fruiting body and total biological benefit were the largest under blue light treatment.The polysaccharide content was the highest under white light irradiation and the lowest under green light.The protein content was the highest under yellow light and the lowest under white light.3.Explore the optimal extraction process of Grifola frondosa polysaccharides.Taking the fruit body of Grifola frondosa harvested in cultivation experiment as raw material,drying and crushing through 100 mesh sieve,using hot water extraction method to extract polysaccharide of Grifola frondosa,taking extraction time,extraction temperature and extraction material to liquid ratio as factors,and polysaccharide content of Grifola frondosa as indicators,using Design-Expert 11 software to optimize by response surface method according to the results of single factor experiment.The optimal extraction conditions were obtained.Under the condition of extraction time of 1.9 h,extraction temperature of 80 ℃,solid-liquid ratio of 1:37(g/m L).the average extraction rate was 14.45 %.The results are close to the predicted value of 14.572 %,the process was stable and feasible.4.Isolation and purification of Grifola frondosa polysaccharides.The extracted crude polysaccharide was further purified.The decolorization experiment results showed that when the amount of activated carbon was 1.8 g,the decolorization rate could reach56.1 % and the polysaccharide retention rate was 80.3 %.After decolorization,Sevage method was used to remove protein from Grifola frondosa polysaccharide,the protein removal rate could reach 36.71 %.5.Functional study of Grifola frondosa polysaccharides.By measuring the free radical scavenging rate of different concentrations of Grifola frondosa polysaccharide aqueous solution in vitro,the antioxidant activity of Grifola frondosa polysaccharides was explored.At the same time,ascorbic acid was used as a positive control.The results showed that: The antioxidant capacity of Grifola frondosa increased with the increase of the concentration of polysaccharide aqueous solution.When the concentration of polysaccharide aqueous solution was 5 mg/m L,the antioxidant activity was the best.The total reduction capacity can reach 0.55.The scavenging rate of DPPH free radical could reach 87.5 %,and the scavenging rate of hydroxyl free radical could reach 94.36 %.