5-Aminolevulinic acid (ALA) is an amino acid that reported to have various health benefits. ALA is found in a variety of foods including sake, but it is not clear what preparation conditions affect ALA in sake. A multiple regression analysis was performed using commercial sake with ALA concentration as the objective variable and various analysis items as explanatory variables. As a result, OD430, rice milling ratio, and amino acidity were extracted as candidates closely related to ALA concentration. Focused on the rice milling ratio, we performed small scale brewing tests using rice with various milling ratios. The results showed that ALA concentration was 2.17 mg/L, 2.41 mg/L, and 2.37 mg/L at 40%, 60%, and 70% of rice milling ratio, respectively, and ALA concentration did not depend on the rice milling ratio. On the other hand, the correlation coefficients with OD430 and OD260 were 0.805 and 0.616, respectively, suggesting that the coloration reaction and yeast content leakage may affect the ALA concentration in sake. In addition, we collected yeast cells and measured the ALA concentration in the crushed extracts. The results showed 20.93 mg of ALA in 1×108 cells of yeast, and the difference between the brewing was small. These results showed that rice polishing ratio and yeast cell contents affected ALA concentration in sake, but other factors were also considered
