Preparation Of High Fischer Ratio Oligo-Peptide From Protease Hydrolysate Of Corn Gluten Meal And Application

High fischer ratio oligo-peptide is a kind of low molecular weight physiological active peptide. It is the production that protease processed the food protein. Because the High fischer ratio oligo-peptide has specially amino acids composition and physiological activity, food and curative domain pay more attention to it. This thesis was conducted on preparation of high fischer ratio oligo-peptide by protease hydrolysis from Corn gluten meal, a byproduct of the wet-milling process, to improve the utilization of corn resource.First, the performance of enzymes was compared. With the index of DH and content of free amino acids, Acalase was selected as the suitable protease to prepare hydrolysate.Orthogonal design (L9(3)4) was adopted to optimize the conditions of hydrolysis. The result was prefered under the condition of pH 8.0, temperature 55 C, ratio of enzyme to substrate 3% and substrate concentration 5%. Simple factor analysis indicated that the optimal time of hydrolysis was 4 hours and the hydrolysate with 11.62% DH was obtained.Based on the comparison of operation parameters, NMWL10000 membrane was used for ultrafiltration of corn gluten hydrolysate and ulrrafiltration pressure was 20KPa.Ion exchange resin was used to remove salt in the hydrolysate. The performance of the treatment was better when flow rate of the hydrolysate was eight times of column volume per hour. The nitrogen retention of the hydrolysate was 81.67% and the ratio of desalinization was 80.95% after passing the ion exchange resin.No.7 active carbon was used to remove free aromatic amino acids by the method of stable absorption. The engineering conditions have been investigated. The optimal conditions were proposed that the ratio of the weight of active carbon to volume of hydrolysate was 1:12, the temperature was 25-35 C and the value of pH was 2.0-3.0. Dynamic elution solution contained 50% 2mol/L ammonia water and 50% ethanol.The result of UV-scanning indicated that active carbon was efficient to absorb aromatic amino acids. The consequence of amino acid analysis showed that the F value of oligo-peptides was 34.71, the content of free amino acid was 6.42%, ultima recovery of product was 11.59%. The product appeared a transparent solution without bitter taste and undesirable flavor, and the content of salt was little.G-25 gel filtration chromatography was used to determination the molecular weight of the high F value oligo-peptides. The result showed that the distribution of molecular weight of the high F value oligo-peptides was consecutive. It ranged from 1000 to 1300 .The studies of peptide beverage and yoghurt were based on high F value oligo-peptides. The formula of nutritive beverage was composed of 1.2% high F value oligo-peptide solution, 4% fruit juice, 6% sugar and 0.15% citric acid. The optimum formula of yoghurt was 20% highF value oligo-peptide solution, 3% culture starter, 6% sugar. The sensory quality of products was well and physical and chemical index were up to standard.Postgraduate: LinLi Major: Food Science Supervisor: Prof. MaYing...