Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7592609 | Food Chemistry | 2015 | 6 Pages |
Abstract
Tryptophan was detected with a flow-injection manifold after reacting with mM order of fluorogenic o-phthalaldehyde (OPA)/thiol reagent (pH 10.0) in the carrier stream (0.63 mL/min). Based on the intra-molecular fluorescence resonance energy transfer of OPA-tryptophan adduct, the difference in fluorescence intensity obtained at 280 and 300 nm excitation was used to detect tryptophan content with satisfactory precision (CV < 6.5% for concentration higher than 0.5 μM), linearity (0.1-10 μM, R2 = 0.9893) and sensitivity (â10 nM). Since tryptophan will decompose during manufacturing non-fermented soy sauce by acid-hydrolysis procedure, the method was used to discriminate pure fermented soy sauces, adulterated soy sauces and chemical soy sauces in less than 5 min. The ratio of tryptophan to total amino acid content served as the index for the judgment, and the results were validated by capillary electrophoresis.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
You-Syuan Gao, Bo-Chuan Hsieh, Tzong-Jih Cheng, Richie L.C. Chen,