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Evaluation of the Concentration and Enantiomeric Purity of Selected Free Amino Acids in Chinese Fermented Soy Beans
Author(s) -
Chen Shushi
Publication year - 2000
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200000134
Subject(s) - chemistry , phenylalanine , racemization , leucine , amino acid , enantiomer , fermentation , food science , derivatization , chromatography , composition (language) , aromatic amino acids , high performance liquid chromatography , organic chemistry , biochemistry , linguistics , philosophy
The total concentration and enantiomeric composition of two selected amino acids (leucine, phenylalanine) in eight different Chinese fermented soy beans were determined after their derivatization with N ‐benzoyl chloride using HPLC system coupled with UV detector. In comparison, fermented soy beans tended to be relatively higher in both the total concentration and enantiomeric composition than raw soy beans. In most samples, phenylalanine was analyzed to have a higher percentage of D‐enantiomer and lower total concentration than leucine. The level of total concentration for examined amino acids was found irrelevant to the storage conditions (e.g., stored in dry or wet form). However, samples preserved in wet form (i.e., soaked in sauce) were likely to have higher percentage of D‐enantiomers (D‐phenylalanine, D‐leucine). In some cases the relative amounts of D‐phenylalanine and D‐leucine exceeded 20% of the individual amino acids. No significant racemization of N ‐benzoyl derivatized amino acids was detected at room temperature. However, the elevation of surrounding temperature caused an increase in the percentage of D‐enantiomers.