米ヌカ内における油脂分の酸価調節に関する研究 (第5報) : 米ヌカリパーゼに対する塩類添加の影響

概要

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Classification for activation and inhibition to rice bran lipase was performed by adding dilute aqueous solutions of some 35 kinds of sulfates, nitrates, phosphates, acetates, chlorides and hydrogen peroxide to rice bran. As a result it was found that the activation and inhibition were largely determined by cation and that anion had little effect on it. Salts that have activated are the each salts of sulfates, nitrates, chlorides, and acetates of manganese and magnesium, and the each salts of sulfates, primary and secondary phosphates and acetates of alkalimetal. The salts which show neither activation nor inhibition are the salts of calcium, barium, ferrous salt and nickel. The salts which show inhibition are the salts of aluminum, lead, zinc, ferric salt, cuprous and cupric salts and mercury. Even the salts which show activation when they are dilute aqueous solution show inhibitive action when their concentration is increased. The hydrolytic velocity of lipase due to addition of salts is inversely proportional to the mol-concentration of salts. As for the effect of addition of salts on the particle diameter of rice bran it shows an abnormal action only on 20-mesh residue but on the smaller particle diameter it shows the same degree of activation or inhibitive action. Hydrogen peroxide shows an inhibitive action to lipase in proportion to its concentration.