Study On Preparation And Antihypertisive Effects Of Angiotensin Converting Enzyme Inhibitory Peptide From Peanut Protein

Extraction process of peanut protein from peanut dregs was optimized by means oforthogonally rotational combination design in this paper. Monitored by Angiotensin convertingenzyme (ACE) inhibitory rate, the alkali proteinase was selected from six commercialproteinases and used for enzymolysis to produce highly active ACE inhibitory peptides;the gel chromatography method was used for the separation and purification, the gelelectrophoresis was used to investigate the distribution of molecular weights, HPLC-MSwas used to preliminarily analyze the product structure, and SHR was selected to testhypotensive activity in animal in vivo. The experimental results were as follows:1. Twice digestion and extraction had a significant effect on protein extraction rate.The alkali treatment and acid precipitation method was adopted and the effects of itstemperature, pH and liquid and material ratio on the extraction rate of protein wereinvestigated in combination with the DPS software analysis. The results indicated that theoptimized range of peanut protein extraction conditions were temperature 32-35℃, pH9.3-9.6, material and liquid ratio 1: 9.7-1: 10.3, twice digestion was performed under thesame conditions with extraction time of 2h each time.2. Alcalase was selected for enzymolysis of peanut protein by the method of responsesurface to produce ACE inhibitory peptides. The effects of temperature, substrateconcentration and the ratio of enzyme and substrate concentration on ACE activity wereinvestigated by using the ACE inhibitory rates as the response value. The results indicatedthat the proper conditions were temperature 53.7℃, substrate concentration 7.72%, theratio of enzyme and substrate concentration 4.18%, pH8.0, and hydrolysis time 120min.3. ACE inhibitory peptides were separated and purified by the method of gelchromatography, and the distributions of molecular weights of different components wereanalyzed by Tricine-SDS-PAGE electrophoresis. The results indicated that the short chainpeptides with the molecular weights of less than 1500D had higher inhibitory rate onACE.4. The highly active ACE inhibitory peptides were analyzed by HPLC-MS and theresults indicated that the single component separated from gel column was the mixture ofpeptides of different molecular weights, and its molecular weights were mainlydistributed in the range of 300-700D.5. The result of acute antihypertensive experiments with spontaneously hypertensiverats (SHR) indicated that blood pressures began to decrease significantly 120min afteroral administration. Compared with the blood pressure before oral administration, theblood pressures 120min, 150min, 180min, and 210min after oral administration were decreased significantly, with the mean arterial pressure (MAP) reduction of 9.9%, 12.2%,14.0% and 13.1%, respectively; and chronic antihypertensive experiments with SHRindicated that the blood pressure of SHR tended to decrease after consecutive oraladministrations, and the blood pressures 2h after oral administration, on day 2, day 5, andday 7 were significantly lower than that of the model group.