Using Waste Beer Yeast Preparation Of Peptides

The waste beer yeast polypeptides are a group of active peptides maken from waste beer protein by autolyzing or hydrolysis.They were studied in this paper that the preparation techniques of polypeptides maken by autolyzing and hydrolyzing with papain or bromelain together with the isolation methods and the measuration of biology activities of polypeptides.Through orthogonal experiment,the optimum autolyzing conditions were as follows:pH6.0, temperature 45°C, concentration of NaCl 4%.The yields of peptides were 49.87 % under this condition. The hydrolysis technique parameters such as temperature, pH, and concentration of enzyme were optimized with Response Surface Methodology. The optimum hydrolysis conditions of papain were as follows: temperature58°C, pH7.05, concentration of enzyme3.03% with the yields of peptides 52.13%.When it comes to the bromelain,the yields of peptides were 50.97% with the optimum hydrolysis conditions: temperature 41°C, pH6.58, concentration of enzyme2.62%.By Isoelectric Point Method the nucleic acid was removed in the solution of waste beer yeast polypeptides. The activated carbon was used to decolour the liquid of waste beer yeast polypeptides and the best contitions can be list as follows: quantity of activated carbon 3%, solution pH3.0, temperature 45°C and adsorption time 3h.Under this condition, the decoloring rate was around 8 % while the loss rate of peptides was 6% approximately.14 kinds of polypeptides were isolated and purified by gel filtration chromatograph and the total antioxidation was measured which indicated that the total antioxidation of E, F, M, D, G components was higher than others. The content of amino acid was tested by automatic amino acid analyzer.Desiccations of polypeptides were maken by vacuum drying and vacuum Freeze-Drying. The results indicated that the mothod of vacuum Freeze-Drying was better than vacuum drying because the former can protect the activities of polypeptides compeletly for its lower temperature.