Studies On The Preparation Of Antioxidant Peptides And ACE Inhibition Peptides By Enzymatic Hydrolysis From Broken-rice

Research and development of active peptide from plant protein sources is oneof popular topic. Broken-rice is an important byproduct of rice processing, and itrich in proteins. in Therefore, extraction of bioactive peptides from broken riceprovides a new method for rice deep processing.This research was aimed to study on preparation of peptides-antioxidantpeptides and ACE inhibitory peptides from enzymatic hydrolysis of broken-rice.This study included follows: the suitable condition of enzymatic hydrolysis formaking antioxidant peptide from broken-rice, methods for purification ofantioxidant peptides with Sephadex chromatography were studied; the suitablecondition of enzymatic hydrolysis for making ACE inhibitory peptides frombroken-rice, methods for purification of antioxidant peptides with Sephadexchromatography were determined. The main results were as follows:(1)Optimun conditions of enzymatic hydrolysis for making antioxidant peptidefrom broken-rice was studied. The results showed that flavourzyme was the mostsuitable for hydrolysis of protease; The optimum hydrolysis condition waspH6.5,4000U/g of enzyme amount,reaction temperature53℃,enzyme hydrolysistime3h,6:1(mL/g) of material-liquid ratio. Under these conditions, the OD700nmofantioxidant peptides reach0.429; Yield of crude antioxidant peptides of broken-ricewas58.21%.(2)The antioxidant peptides made by hydrolyzing broken-rice was separatedby Sephadex G-50and Sephadex G-25. The results showed that the peptidescollected in the third elution peak has the best antioxidant activity, the distributionof the antioxidant peptides molecular weight of the third collected was790-1480; itwas purified basically by HPLC analysis; it was composed of12amino acids, richin essential amino; Yield of antioxidant peptides of broken-rice was10.8%.(3)Optimun conditions of of enzymatic hydrolysis for making ACE inhibitorypeptide from broken-rice was studied. The results showed that flavourzyme wasthe most suitable for hydrolysis of protease; The optimum hydrolysis conditionwas pH7.0,4000U/g of enzyme amount, reaction temperature55℃, enzyme hydrolysis time3h,3:100(g/mL) of material-liquid ratio. Under these conditions,the inhibition rate of ACE inhibitory peptides reach81.4%; Yield of crude ACEinhibitory peptides of broken-rice was10.8%.(4)The ACE inhibitory peptides made by hydrolyzing Broken-rice wasseparated by Sephadex G-50and Sephadex G-25. The results showed that theinhibition rate of peptides collected in the third elution peak reach86.21%, thedistribution of the inhibition peptides molecular weight of the third collected was390-1090; it was composed of13amino acids, rich in essential amino; Yield ofACE inhibitory peptides of Broken-rice was7.23%.