We. seven sake brewers in Numazu district of Shizuoka Prefecture; agreed to brew unitedly the first moto at one fixed place in the cold district. We brought rice and water respectively andbrewed it at the same time and at the same place. We tried to find how different waters givedifferent results in brewing. We arrived at the following, conclusion: (1) The water which contained much calcium, magnesium, or chlorine was not necessarily good in saccharifying and in fermentation. (2) The moto which fermented early contained little amino acid and a smal number of yeasts.
A rapid accurate determination of NaCl in soy-sauce is very diff icult. Mohr's methood is unsuitable, because (1) organic substances hinder the color change of reagents, and (II) the color of soy-sauce resembles that of Ag2CrO4, and the end point of titration is obscure. The author investigated on direct argentometric titration of soy-sauce and obtained the following results. 1) In the titration of Cl- in soy-sauce with Ag+ satisfactory results are obtained in acidic solution (adjusted by acetic acid, optimum pH range, 2.7-3.4) with bromophenol blue as absorption indicator. The results are accurate in the presence of hundreds of organic compounds such as, various amino acids, peptones, peptides, proteins, amines, acetals, ketones, aldehydes, carbohydrates, alcohols, acids (lactic succinic, acetic, ketonic, etc), heterocyclic compounds (furfural etc), melanines, and their derivatives and polymers. In this case, the color change becomes extremely sharp by addition of the peptone. 2) Metanil yellow, tropaeolin 0 0, fluoresceim, dichlorofluorescein, etc cannot be used chiefly nwing to the interference by proteins and their hydrolyzid or fermented products. Tetrabromophenol-tetrabromosulfonphthalein is also applicable.(part II)
The growth factor of Bac. hyochi showing variable growth in the course of saké brewing are closely connected with amino acids, among which methionine, cystine, phenylalanine, tyrosine and glutamic acid are the especially important factors.