Study On Antioxidant Peptide And ACE Inhibitory Peptide Of Wheat Gluten Hydrolysates

In this paper, taking wheat gluten as raw material, hydrolyzed by four different proteases(papain, neutral protease, protamex, alkaline protease), and the enzymatic hydrolysis conditions were optimized by single factor and orthogonal experiment, ob-tained four kinds of wheat gluten hydrolysates. Their antioxidant activity and angi-otensin converting enzyme(ACE) inhibitory activity were investigated. Moreover, the hydrolysates of highest inhibiting activity and antioxidant activity were isolate, purification and identification. The results were as follows:First of all, taking nitrogen solubility index(NSI), the solubility of TCA and DPPH radical scavenging activity as index, four single factor( the concentration of substrate, enzyme dosage, enzymolysis time, enzymolysis temperature) of orthogonal experimenton were optimized to obtain high antioxidant activity of the hydroly-sates. Taking NSI, the solubility of TCA and ACE inhibition rate as index, four sin-gle factor( the concentration of substrate, enzyme dosage, enzymolysis time, en-zymolysis temperature) of orthogonal experimenton were optimized to obtain high antioxidant activity of the hydrolysates. The experimental results show that the an-tioxidant activity of peptide hydrolysis conditions were: hydrolyzed by protamex, 3h of enzymatic hydrolysis time, 25% of substrate concentration, 0.8% of the amount of enzyme, 35 of enzymatic hydrolysis temperature; ACE inhibitory ℃peptides of enzymatic hydrolysis conditions were: hydrolyzed by alkaline protease, 3h of en-zymatic hydrolysis time, 25% of substrate concentration, 0.8% of the amount of enzyme, 60 of enzymatic hydrolysis temperature.℃Secondly, the hydrolysates of highest inhibiting activity and antioxidant activity were isolate, purification by ultrafiltration, G-15, RP-HPLC, the results showed that Mr <1 KDa of peptide showed higher antioxidant activity and ACE inhibitory rate, the antioxidant activity of purified up to 76.34% and ACE inhibitory components the activity of up to 81.03%.These two peptides were identified by ESI-TOF-MS method. The results show that high molecular weight antioxidant peptide was 730.83 and the amino acid sequence of Gln-Gln-Gln-Pro-Arg(QQQPR), high ACE inhibitory pep-tides with molecular weight of 630.89 and the amino acid sequence of Trp-Phe-Gln- Pro(WFQP).