Kodama Shuji, Yamamoto Atsushi, Matsunaga Akinobu, Matsui Keizou, Nakagomi Kazuya, Hayakawa Kazuichi
Toyama Institute of Health, 17-1 Nakataikoyama, Kosugi-machi, Toyama 939-0363, Japan.
J Agric Food Chem. 2002 Feb 13;50(4):767-70. doi: 10.1021/jf011098j.
The amounts of D- and L-lactic acids during the brewing process of sake were determined by capillary electrophoresis using 2-hydroxypropyl-beta-cyclodextrin as a chiral selector. Because L-lactic acid, which prevents the growth of nonuseful microorganisms, is a raw material of sake, the ratio of L-lactic acid to total lactic acid is almost 1.0 at the initial stage of sake brewing. During brewing, the ratio decreased gradually and finally reached 0.39. Yeast (Saccharomyces cerevisiae) for sake brewing produced D-lactic acid, but not L-lactic acid in a culture medium. These results suggest that the decrease in the ratio of L-lactic acid to total lactic acid during sake brewing resulted in D-lactic acid production by yeast. The ratios in 18 brands of sake obtained commercially ranged from 0.23 to 0.78. The levels of D-lactic acid in sake (140-274 mg/L) were in a narrower range than those of L-lactic acid (61-461 mg/L). Although the D-lactic acid level in sake did not correspond to total lactic acid level, the L-lactic acid level correlated well with total lactic acid level (R(2) = 0.867). These results suggest that the ratio of L-lactic acid to total lactic acid in sake reflected the amount of L-lactic acid added at the initial stage of sake brewing.
采用以2-羟丙基-β-环糊精为手性选择剂的毛细管电泳法测定了清酒酿造过程中D-乳酸和L-乳酸的含量。由于L-乳酸是清酒的一种原料，且能抑制有害微生物的生长，在清酒酿造初期，L-乳酸与总乳酸的比例几乎为1.0。在酿造过程中，该比例逐渐下降，最终降至0.39。用于清酒酿造的酵母（酿酒酵母）在培养基中产生D-乳酸，但不产生L-乳酸。这些结果表明，清酒酿造过程中L-乳酸与总乳酸比例的下降是由酵母产生D-乳酸所致。18个市售清酒品牌的该比例在0.23至0.78之间。清酒中D-乳酸的含量（140 - 274 mg/L）范围比L-乳酸（61 - 461 mg/L）窄。虽然清酒中D-乳酸含量与总乳酸含量不对应，但L-乳酸含量与总乳酸含量相关性良好（R² = 0.867）。这些结果表明，清酒中L-乳酸与总乳酸的比例反映了清酒酿造初期添加的L-乳酸量。
