Carlavilla Davinia, Moreno-Arribas M Victoria, Fanali Salvatore, Cifuentes Alejandro
Department of Food Analysis, Institute of Industrial Fermentations (CSIC), Madrid, Spain.
Electrophoresis. 2006 Jul;27(13):2551-7. doi: 10.1002/elps.200500909.
The formation of D-amino acids (D-aa's) in many fermented foods depends, among other factors, on the particular fermentation conditions, the action and autolysis of the microorganisms involved. In this sense, the analysis of chiral amino acids is an interesting analytical strategy for food scientists, since these compounds can be used as bacterial markers and can help, e.g., to detect adulterations, microbiological contaminations, etc. In this work, a fast and sensitive method based on MEKC-LIF has been developed to analyze and quantitate L-amino acid (L-aa) and D-aa in vinegars. The chiral MEKC-LIF procedure uses 100 mM sodium tetraborate, 30 mM SDS, and 20 mM beta-CD at pH 9.7 as running buffer, obtaining a good separation of the main vinegar L-/D-aa previously derivatized with fluorescein isothiocianate. Namely, L/D proline, alanine, arginine, glutamic, and aspartic acid, plus the nonchiral amino acid gamma-aminobutyric acid are separated in less than 20 min with high efficiency (up to 720,000 plates/m) and good sensitivity (LODs lower than 16.6 nM were achieved). Several D-aa's were detected and quantified in balsamic, sherry, white wine, and cider vinegars using this MEKC-LIF procedure, observing interesting differences in their L-aa and D-aa profiles and contents.
许多发酵食品中D-氨基酸(D-aa's)的形成除其他因素外,还取决于特定的发酵条件、所涉及微生物的作用和自溶。从这个意义上说,手性氨基酸分析对食品科学家来说是一种有趣的分析策略,因为这些化合物可用作细菌标志物,例如有助于检测掺假、微生物污染等。在这项工作中,已开发出一种基于MEKC-LIF的快速灵敏方法,用于分析和定量醋中的L-氨基酸(L-aa)和D-氨基酸。手性MEKC-LIF方法使用100 mM硼酸钠、30 mM SDS和20 mM β-环糊精,pH 9.7作为运行缓冲液,对先前用异硫氰酸荧光素衍生化的主要醋L-/D-aa实现了良好的分离。即,L/D脯氨酸、丙氨酸、精氨酸、谷氨酸和天冬氨酸,加上非手性氨基酸γ-氨基丁酸在不到20分钟内高效分离(高达720,000板/米)且灵敏度良好(检测限低于16.6 nM)。使用此MEKC-LIF方法在香醋、雪利酒、白葡萄酒和苹果醋中检测并定量了几种D-氨基酸,观察到它们的L-氨基酸和D-氨基酸谱及含量存在有趣的差异。