Enantioselective amino acid metabolome analysis of the Japanese traditional black vinegars (amber rice vinegar, Kurozu) was performed using two-dimensional high-performance liquid chromatography combining a microbore-monolithic ODS column and narrowbore-enantioselective columns. d-Amino acids, the enantiomers of widely observed l-amino acids, are currently paid attention as novel physiologically active substances, and the foodstuffs and beverages containing high amounts of d-amino acids are the subjects of interest. In the present study, the amino acid enantiomers were determined by two-dimensional HPLC techniques after pre-column fluorescence derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole. In the first dimension, the amino acid enantiomers are separated as their d plus l mixtures by the reversed-phase mode, then the d-amino acids and their l-counterparts are separately determined in the second dimension by the enantioselective columns. As a result, large amounts of d-Ala (800-4000. nmol/mL), d-Asp (200-400. nmol/mL) and d-Glu (150-500. nmol/mL) were observed in some of the traditionally produced Kurozu vinegars. Relatively large or small amounts of d-Ser (50-100. nmol/mL), d-Leu (10-50. nmol/mL) and d-. allo-Ile (less than 20. nmol/mL) were also present in these samples. Developmental changes in the d-amino acid amounts during the fermentation and aging processes have also been investigated.
|Number of pages||6|
|Journal||Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences|
|Publication status||Published - Sept 1 2014|
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Clinical Biochemistry
- Cell Biology