2012 年 40 巻 4 号 p. 47-56
In general, enzymes are essential molecules for maintaining of life and are composed of various amino acids. The amino acids synthesized chemically contain both D- and L-amino acids, but enzymes contain exclusively L-amino acids in their peptide chains. This fact leed to the origin of life, and many theories were mentioned but anyway both D- and L- amino acids co-existed at the beginning of the forming of the earth. Accordingly, D-amino acids exist more than 50 milion years ago in nature, but the existence of D-amino acids have been ignored until the analytical methods for D-amino acids develope. Recently, much attention has been payed for the relationship between D-amino acid in food and their function in life.
In this work, I will describe D-amino acid in food, especially in sake, and discuss about occurrence, production mechanism, and function of D-amino acid in sake. I analyzed D- and L-amino acids contents of 141 kind of sake by combination of 3 diffenrent chiral derivertization methods for high-performance liquid chromatography. I analyzed the relationship betwee D- or L-amino acid content and taste of sake using principle component analysis. I found that D-amino acid content of sake increased when it was produced with Kimoto. The lactic acid bacteria contained Kimoto produced extracellularly D-alanine, D-aspartic acid, and D-glutamic acid. Principle component analysis revealed that D-alanine, D-aspartic acid, and D-glutamic acid in sake increased umami and total evaluation of sake. This new function of D-amino acid in food will make various functional foods and contribute to human health in daily life.
