| In this paper, the aim of this study was to produce ACE inhibitory peptides from Zeinusing enzymes yielded by different strains. Especially, the enzymes obtained from microbesused, which will give some supports to the further development of the antihypertensive drugand functional food.Bacillus natto and Aspergillus oryzae IF-39were selected from many kinds of strains,which had high ability to yield an alkaline proterase or a neutral protease. The optimal cultureconditions for Bacillus natto were confirmed as followed: radio of wheat bran to soybeanMeal:2:3, pH:9.0, water content:80%, bacteria quantity:1.5mL,37.5℃for72h. Besides,the optimal culture conditions for Aspergillus oryzae IF-39were confirmed as followed: radioof wheat bran to soybean meal:3:2, pH:8.0, water content:60%, bacteria quantity:3rings,28℃for96h.The hydrolisis conditions of Bacillus natto and Aspergillus oryzae IF-39were studied. Inexperiments, The optimum conditions for Bacillus natto were substrate concentration:5%,enzyme concentration:8000u/g, pH:9.5, temperature:40℃, hydrolisis for180min. Theoptimum conditions of Aspergillus oryzae IF-39had been found as followed: substrateconcentration:10%, enzyme concentration:8%, pH:7.5, hydrolysis temperature:35℃andhydrolysis for120min.After comparison, Sephadex G-25was chosen as the medium for purification ofhydrolysate and the purification conditions were confirmed as followed: loading amount:1.5mL, elution speed:1.0mL/min, pH:9.0, boric acid buffer used as eluant. The purificationconditions for hydrolysate by Aspergillus oryzae IF-39had also been found, loading amount:1.5mL, elution speed:1.5mL/min, pH:7.5, phosphate buffer used as eluant.The hydrolysates obtained from the two strains had been purified into five components,with a higher inhibition in Component3,4and5. Among the hydrolysates of Bacillus natto,Component3showed the highest inhibition of89.4%while the Component4was as higher as85.2%in another hydrolysates. |
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