Research On Preparative Technique Of Polypeptide From Tricholoma Mongolicum

The research mainly investigated preparative technique of polypeptide from Tricholomamongolicum. Tricholoma mongolicum is a famous edible mushroom well-known home andabroad. It is fragrant and tasty, abundant in nutrition. Protein content of Tricholomamongolicum fruiting body is high. Researches involve Tricholoma mongolicum mainlyfocused on ecology, and there were few reports contributed to functional food productsdevelopment. Polypeptide is prepared from protein by enzyme hydrolysis and isolation. It isusually a mixture of low molecular weight polypeptide which is composed of 2～50 aminoacids. Polypeptide has approximately the same amino acid composition with the originalprotein. It is rich in content of essential amino acid, and equilibrium in composition.Polypeptide is easy to digest, it has excellent functional properties which the original proteindoes not have, and can be utilized in many fields. Polypeptide can be the best nutritionsubstance for protein supplement.The optimum technique parameters of supercritical CO₂ fluid extraction and extrusiontechnology were determined by orthogonal test. Supercritical CO₂ fluid extraction caneffectively remove lipids and the optimum conditions of supercritical CO₂ fluid extractionwere: pressure 25 MPa, temperature 35℃, time 120 min, and CO₂ flow 20 L/h. Under theseoptimal parameters, the extraction rate was 1.09%. Extrusion technology treatment canimprove the solubility of Tricholoma mongolicum protein and the concentration of solublepeptide. The optimum conditions of extrusion technology treatment were: water content 45%,temperature 135℃, feed speed 30 kg/h, rotational speed 200 r/min, and the concentration ofsoluble peptide could achieve 4.40%. Compared with the non- extrusion technologytreatment material which the concentration of soluble peptide was 1.63%, the concentrationof soluble peptide of extrusion technology treated one was improved 2.70 times, ideal for thenext step's enzyme hydrolysis. Polypeptide was prepared from Tricholoma mongolicum by two-stage enzyme hydrolysis.The first stage use alcalase as hydrolysis enzyme to prepare polypeptide, and the second stagechoose flavourzyme to adjust the flavor. The preparative technique of polypeptide fromTricholoma mongolicum by alcalase was studied, and the effects of temperature, time, andconcentration of substrate, concentration of enzyme, and pH on NaOH consumption wereanalyzed. Based on single factor analysis, orthogonal test was designed to discuss the effectsof multi-factor conditions to optimize the hydrolysis conditions. The optimum hydrolysisparameters were: temperature 55℃, time 2.5 h, concentration of substrate 2%, concentrationof enzyme 1.5% (E/S), and the NaOH consumption was 3.50 mL.The experiment invested the de- polysaccharide effects of ethanol precipitation bycomparative analysis. The experiment treated enzyme hydrolysis product from Tricholomamongolicum with ethanol solution of different volume and concentration, and the mass ofpolysaccharide and the concentration of soluble polypeptide were the evaluating factors. Theoptimum conditions for ethanol precipitation were: 65% ethanol solution of three timesvolume.The yield of polypeptide from Tricholoma mongolicum in this research is 32.10%. Thepolypeptide from Tricholoma mongolicum could be used in functional food and the researchmay provide theoretical foundation and experimental evidence for further research.