Isolation And Purification Of Corn Antioxidant Peptides And Their Complete Absorption Studies

This research is a part of the Jilin provincial science and technology development project--"The Key Technology Research on Large-Scale Utilization of Corn Protein Powder Processing Series of Active Peptide Products"(20150204032NY).In this study,we used corn protein powder as the research object to obtain antioxidant peptides by enzymatic hydrolysis,followed by the isolation and purification,and we carried out the activity evaluation of corn antioxidant peptide,studied the relationship between antioxidant activity and peptide sequence,spatial structure.Finally,the complete absorption of antioxidant peptides from maize source was studied.(1)In the study of isolation and identification of purified antioxidant peptides in corn,corn protein powder was chosen as the research object.After enzymolysis,ultrafiltration and freeze-drying process,two different molecular weight MW<1 kDa(CPH1)and 10~30 kDa(CPH2)of corn antioxidant peptide powder were obtained.The components of molecular weight 10~30 kDa were purified by Sephadex G-25 gel chromatography,and CPH2-III were identified by MS/MS.Four antioxidative peptides were obtained,and the amino acid sequences were AGI/LPM(487.62 Da)and HAI/LGA(467.53 Da),respectively.(2)In the study of antioxidant activity evaluation of peptide,the activities of antioxidant peptide were evaluated by ORAC oxygen free radical scavenging,scavenging hydroxyl radical activity,ROS activity and antioxidant activity in cell.The relationship between the antioxidant activities of the peptide and its sequence and spatial structure was discussed.The conclusions were listed as follows:Antioxidant peptide AGLPM has the strongest antioxidant activity;in the peptide sequence,the antioxidant activity of the antioxidant activity of Leu containing peptides may be higher than the peptide containing Ile(not C-or N-terminal);The alpha helix structure may play a more important role than the irregular curl in the effect of the antioxidant activity of the peptide.(3)In the complete absorption study of the antioxidant peptide AGLPM,a Caco-2 cell membrane model was established.HPLC was used to evaluate the complete absorbability of the peptide AGLPM.After 21 days of culturing Caco-2cells,the value of TEER was stable at 400?·cm~2,and the integrity of cell monolayer was good.Meanwhile,the alkaline phosphatase activity on the AP side was 12.29 times that of the BL side,and the Caco-2 cell membrane had obvious polarity differentiation.The Caco-2 cell membrane was completely polarized.The stability of AGLPM and the absorption of Caco-2 cell membrane detected by HPLC showed that the antioxidant peptide AGLPM could be absorbed completely.