탁주효모에 자외선을 조사(照射)시켜 얻은 변이주(變異株)의 생산성(生酸性)에 미치는 pH 및 온도의 영향과 생성한 산을 PPC법 및 p-oxidiphenyl 법(法)으로 검정하고 또한 이균(菌)을 이용한 탁주양조시험을 하여 다음과 같은 결과를 얻었다. 1. 산(酸) 생산변이주의 생산능(生酸能)은 $25{sim}35^{circ}C$ 하(下)에서는 별 차이가 인정되지 않았다. 2. 생산(生酸)변이주는 pH 4이하(以下)에서는 거의 산을 생성하지 않았으나 pH 4 이상에서는 중성(中性)으로 감에 따라 급격히 산을 생성하여 pH $5{sim}7$하에서는 48시간의 배양으로 $0.5{sim}0.7%$의 생산량(生酸量)을 보였다. 3. 변이주가 생성한 산을 검정한 결과 젖산으로 인정되었다. 4. 산(酸) 생성변이주의 효모(酒母)를 사용하면 담금원료의 5% 입국(粒麴)으로도 20% 입국(粒麴)을 사용할 때와 같은 양질의 탁주를 제조할 수 있었다. 5. 당화제(糖化劑)로서 분국(粉麴)만을 사용하여 모균주(母菌株)의 주모(酒母)와 산 생성변이주의 주모(酒母)를 시차적으로 첨가함으로서 양조기간의 단축과 양질의 탁주를 제조할 수 있었다.
This experiment was conducted to study the effects of temperature and pH upon the acid productivity of the acid producing mutant induced by the treatment of ultraviolet light, and to identify the producing acid by PPC and p-oxydiphenyl method. Chemical composition of Takju mash brewed with selected yeast and producing acid were observed and the results were as follows. 1) There was no apprecible difference in acid producing activity of mutant at $25^{circ}C;to;30^{circ}C$. 2) The acid producing activity of mutant was little below pH 4 and was gradually increased according to approach nenutral, and the accumulation of acid was amounted to 0.5-0.7% as a lactic acid at pH 5 to 7 within 48 hrs of fermentation. 3) The acid produced by mutant was detected to the lactic acid. 4) In the cases of the Takju was brewed with the starter from the acid producing mutant the requirement of Ipkuk was 5% for all the raw materials, on the contrary, using orginal strain the requirement of Ipkuk was 20%. 5) In the case of both starters from the acid producing mutant and orginal strain were added at different brewing times, and only Bunkuk was used as a saccharifying agent (without Ipkuk), Takju was able to brewed more repidly and successfully than the case of general process.
