The carbohydrate and alcohol contents of various types of vinegar, including traditional balsamic vinegar from Modena, "Modena Balsamic Vinegar," wine vinegar and vinegar prepared from apple must, were studied. Assays were carried out using enzymatic techniques, which are particularly suited to this type of analysis. Determination of the components of the various vinegars, and of their interrelationship, is a crucial factor in the characterization of traditional balsamic vinegars.
The carbohydrate and alcohol contents of various types of vinegar, including traditional balsamic vinegar from Modena, "Modena Balsamic Vinegar," wine vinegar and vinegar prepared from apple must, were studied. Assays were carried out using enzymatic techniques, which are particularly suited to this type of analysis. Determination of the components of the various vinegars, and of their interrelationship, is a crucial factor in the characterization of traditional balsamic vinegars.
25
A simple and rapid method for the quantitative determination of eight tryptophan (via kynurenine) metabolites is described. The following compounds can be determined even when present in the same sample of urine, blood or spinal fluid: kynurenine, 3-hydroxykynurenine, Nα-acetylkynurenine, anthranilic and 3-hydroxyanthranilic acids, kynurenic and xanthurenic acids, 8-methyl ether of the xanthurenic acid.
The compounds are separated by means of two-dimensional chromatography. Spots of kynurenic acid, Nα-acetylkynurenine and xanthurenic acid 8-methyl ether are eluted with ethanol and the absorbancies are read in the ultraviolet.
An acetic solution of p-dimethylaminobenzaldehyde serves as eluent and chromogenic reagent for the spots of kynurenine and anthranilic acid.
Spots corresponding to 3-hydroxykynurenine, xanthurenic and 3-hydroxyanthranilic acids are eluted with water and determined by means of the color developed with a diazo reagent.
Kynurenic and xanthurenic acids can also be determined conveniently by means of a spectrophotofluorometric procedure.
The reproducibility of the results is satisfactory over a large range, and very good for amounts of 1 to 5 µg.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.