Preparation And Property Research Of Ganodorma Lucidum Peptide-selenium Chelate

In this paper,with Ganoderma lucidum as raw material,protein was extracted by alkali-dissolving-and-acid precipitating method,followed by compound protease digestion to obtain peptides,and then peptide-selenium chelate was prepared.The physical and chemical properties of Ganodorma lucidum bioactive peptide-selenium chelate were analyzed after structure characterization.The results provide new ideas for the application of Ganoderma lucidum.(1)Basic composition of the Ganoderma lucidum,including amino acid,protein,crude fiber,and trace elements,were analyzed by modern science and technology.The results showed that Ganoderma lucidum had rich amino acid,protein,trace elements and contained appropriate content of crude fiber and low fat,which was a high quality raw material for peptide-selenium chelate.(2)Alkali-dissolving-and-acid-precipitating method was used to extract protein from Ganoderma lucidum.Through single factor tests and response surface method optimization,the optimum condition of protein extraction was as follows:liquid ratio(v/w)120:1,reaction temperature 50?,alkali dissolving pH 10.0,reaction time 60 min.Under this condition with pH 3.0,the maximum extracting rate of Ganoderma lucidum protein complexes was 39.7%.(3)To obtain peptides,compound proteases were used to hydrolyse Ganoderma lucidum protein.And then chelating technology of Ganoderma lucidum protein peptide with sodium selenite was optimized by response surface method.The optimized technology was:enzymolysis time of 30 min,ratio of sodium selenite(0.5 mol/L)to polypeptide solution 1:2(v:v),pH 9.0,reaction temperature of 75?,and reaction time of 60 min.The optimized technology led to selenium content in the chelate of 2985.89±10.59?g/g.(4)The physical and chemical properties of Ganoderma lucidum protein peptide-selenium chelate were studied.It was confirmed by sodium sulfide statutory testing that peptides and selenium in the compound existed in the form of chelate,which is a new material instead of single peptide or sodium selenite.By the composition analysis,this chelate contained 2.95%selenium.Through the determination of solubility,the chelate could be dissolved in water easily.The solubility increased with increasing pH in the scope of the pH2.0-8.0,and it was easy to dissolve in alkaline solution than acid.Moreover,this chelate had certain antioxidant capacity.(5)Structure characterization of Ganoderma lucidum protein peptide-selenium chelate was studied.The results of Fourier infrared spectrum(FTIR),fluorescence spectrum and ultraviolet spectrum indicated that this chelate had different structure characteristics compared with Ganoderma lucidum peptides or sodium selenite.