Study On Preparation Of ACE Inhibitory Peptides From Enzymatic Hydrolysis Of Soybean Protein

This topic use the direct enzymolysis and bacillus natto fermentation respectively for theenzymolysis of soybean protein, and produce short peptide possessing a kind of inhibitoryactivity acting on ACE, aiming to improve the value of the soybean protein.The experimentoptimizes the best technological conditions of two different ways to make the active peptide,then make some comparison in order to find the best method and carry a100L amplificationexperiment. Thus initially set up the process flows of making the inhibitory activity acting onACE with soybean meals protein. Some conclusions are as follows:(1) The pretreatment of soybean meals: after the experiments of acid-base soaking,ultrasonic and heat treatment, the results shows that all of the three ways are helpful to inhibitthe ACE and to the growth of bacillus natto. Take all the factors into consideration, I do somepretreatment to the enzymolysis substrate soybean meal before heating, and do ultrasonicpretreatment to the fermentation substrate soybean meal.(2) hydrolysis: the inhibitory peptide acting on ACE produced by alkali protease throughhydrolysis the most effective. The condition is that substrate concentration is5%with enzymeconcentration at5000U/g in4hours. When using trypsin in hydrolysis of soybean meal, thebest condition is substrate concentration at5%with enzyme concentration at800U/g in6hours.In addition, the inhibitory peptide acting on ACE produced by alkali protease is the mosteffective, reaching at48.67%(3) Aqueous enzymatic extraction: optimizing the conditions of stepwise hydrolysis toalkali protease and trypsin by Response Surface Analysis (RSA), and determine the bestconditions for alkali protease is concentration at5100U/g, pH9, hydrolysis in2hours; Trypsinconcentration at850U/g, pH8, hydrolysis in2hours.In this condition, after test, ACE inhibitionrate reached73.31%through alkali protease and trypsin hydrolysis successively.(4) soybean meal of liquid bacillus natto fermentation: to the bacteria levitation liquid ODvalue as the index, carbon and nitrogen source proportion is1:5, power80W of ultrasonicpretreatment soybean meal culture medium4.32minutes, fermentation cultivation condition forpH6.16, the temperature is35.5℃, the bacteria levitation liquid concentration reaches maximum1.635.In these conditions wave bed180RPM at training20h, get the fermented liquid inhibitoryactivity ACE highest to ACE48.71%. (5) The preparation of100L inhibitory peptide acting on ACE: compared with small-scaletest (2L size) conditions, the enzymatic hydrolysis time is long, the first step in the enzymatichydrolysis lasts2hours, the second step lasts2hours. After the enzymatic hydrolysis, the liquidchromatography will be used for the determination of the inhibitory activity of enzymatichydrolysate acting on ACE, then found that activity decreased significantly compared with thesmall-scale test, only reaches at53.04%.