Study On The Active Glutamine Peptides Made From Wheat Protein By Enzymatic Hydrolysis

The thesis studied on the manufacturing technologies of bioactive peptides, which contained abundant Gln, made from wheat proteins by proteatic hydrolysis. The methods to analyze the content of Gln, the composition of amino-acids, and the distribution of molecular weight of peptide were developed as well.Firstly, the quantitative analysis method of Gln of peptide was established. Gln in peptides was protected by reacting with [bis(trifluoroacetoxy)iodo]benzene (BTI) for 2 hours at 50℃ to prevent the Gln to be transformated into glutamic acid in the succedent acid hydrolyzation. Then after being derived by phenylisothiocyanate (PITC), Gln was quantificated by RP-HPLC (C₁₈ column, UV-detector) using the external standard method.Secondly, the analysis of the composition of amino-acids and the distribution of molecular weight of peptides were studied. 18 kinds of amino acid could be separated simultaneously and quantificated by UV-detector after eluted gradiently by RP-HPLC, using PITC as precolumn derivation reagent. Gel filtration chromatography was used in the analysis of the distribution of molecular weight in of peptides, chromatograghic column was TSK-GEL G2500PWXL(7.8*300mm), a mixture of trifluoroacetic acid-acetonitrile-water(0.1:45:55) was used as eluent, logaritathm of molecular weight was linear with retention time.Then, the technology to produce Gln peptides was optimized. After the research on such factors as enzyme species, substrate concentration, enzyme concentration, pH, temperature and reacting time of enzymatic reaction system, the optimal condition of enzymatic treatment was obtained as follows: acid protease, [S]=15%, E/S=5% (Activity of enzyme is 50000u/g) , pH=2.5, 45℃, 3hours.Lastly, enlarged experiment was carried out in 11 liter reactor and got a product which contained 4.6%water and 73.3% protein, among the protein 11.2% was Gln, and the yield was 43.2%.