チーズの熟成に関する研究

V. チーズ内におけるコウジカビの酵素作用(その2) コウジカビ•プロテアーゼの調製

抄録

In the previous paper, it was shown that the rate of protein degradation in cheese by the action of Aspergillus was almost the same as that by the action of Penicillium roqueforti. The distribution of nitrogenous compounds in cheese, however, was different by the strain of Aspergillus used for production of cheese. Therefore, it is necessary to examine the action of protease in Aspergillus during cheese ripening. This paper deals with protease yields of Aspergillus, separating methods of the protease, and its proteolytic action.
(1) Among various strains of Aspergillus, Asp. oryzae-chosen B was useful with its yields of extracellular protease while culture growing in medium A (for shaking culture) and medium E (for solid culture) at 30°C for 4 to 6 days.
(2) An enzyrme solution containing 50% acetone was chilled at 0°C, from which protease was separated by the method of casein adsorption. This separating method f-was the most effective for the purpose of adding proteasa of Asp. oryzae-chosen B into cheese.
(3) Asp. oryzae-chosen B was cultivated in medium A and medium E at 30°C for 4 to 6 days and protease was separated, by separating method f. from the enzyme solution produced. No obvious difference was found in the distribution of nitrogenous compounds in casein substrate hydrolyzed by between the two sources of protease production.