Study On Preparation And Property Of Glutamine-bioactive Peptides

Glutamine is a conditionally essential amino acid,which plays a very important role in metabolism.The instability and low solubility of free Gln hamper its exploiture and use.Glutamine-bioactive peptides can overcome these shortcomings,but only the Glutamine-bioactive peptides such as Gly-Gln and Ala-Gln were applied in clinic presently,and the high price,low synthesis quantity also limit application of the two synthesis dipeptides.In this study,with wheat protein which is a kind of cheap and convenient protein resources as material,Glutamine-bioactive peptides were prepared by enzyme hydrolyzing wheat protein.In addition,physical and chemical properties and biology function were also investigated.Through odd factor tests,the optimum conditions of extraction were obtained as follows:30℃,NaCl%=2%,water:flour=1,pH7.0.Wheat protein was gained in this condition.Its protein content was 79.26%,the content of Gln was 43.25%,and the solubility of protein was12.90%,Glutamine-bioactive peptides were prepared by hydrolyzing wheat protein with Alcalase and Trypsin one by one.Selecting DH and the content of Gln as indexes,through orthogonal experiments,the optimum conditions of enzymatic hydrolysis were obtained as follows:Alcalase at 60℃,PH9.5, S%=4%(W/V) and E%=1.5%(w/w) for 1 hour,DH=21.25%,Trypsin at 40℃, PH9.0 and E%=1.5%(w/w) for 2 hours,increasing DH=3.30%.The final yield of bioactive peptides was 61.38%,the content of Gln was 33.14%.Studying on the physical and chemical properties,the TCA-NSI was 83.33%,the average peptide length was 4.07,the content of salt was 0.29g/L, the peptides was composed of relative molecular mass 2857 and 2117 by HPLC,the percentage was 35.69%and 64.31%.Compared with dissociative glutamine,and the osmolality was obviously reduced,solubility was obviously increased.The antioxidation and anti-Fatigue functions of Glutamine-bioactive peptides were investigated.The results of experiment in vitro showed that the antioxidative activities,reductive activities and hydroxyl radicals scavenging activities became stronger as the increasing concentrations.The experiment of antioxidation and anti-Fatigue effects in vivo were processed with mice as subjects.Compared with the control group,the results indicated that the high-dose glutamine-bioactive peptides could obviously improve the activities of SOD and reduce the contents of MDA in liver and kidney.In addition,it could prolong the swimming time and living time of mice,enhance the anti-fatigue abilities.