Concentration of headspace, airborne and aqueous volatiles on Chromosorb 105 for examination by gas chromatography and gas chromatography-mass spectrometry

Volatile Compounds Associated with Spoilage of Vacuum-Packaged Sliced Luncheon Meat by Brochothrix thermosphacta

By using gas chromatography-mass spectrometry, seven volatile compounds were identified in vacuum-packaged sliced corned beef spoiled by Brochothrix thermosphacta under aerobic conditions. Acetoin and diacetyl appeared to be of major sensory significance.

Artifacts and contaminants in the analysis of food flavor

The qualitative and quantitative complexity of food flavor makes its complete analysis rather difficult, involving a series of necessary successive steps, from the transport of the samples to the laboratory to the final quantification of the volatiles in the extract. However, because of the minute amounts of most odorous substances in food, these numerous manipulations of the sample are often the cause of alterations of the flavor, and complementary techniques are generally recommended to get a clear idea of its original composition. Arguments and clues, from 95 publications dealing with the analysis of various types of food, demonstrating that some of the volatile substances finally identified could have been in fact contaminants or artifacts arising from the analysis itself are presented. For practical reasons, the logical sequence of treatments successively applied to the sample throughout the flavor analysis is adopted.

New metabolites in isovaleric acidemia

Two metabolites, 4-hydroxyisovaleric acid and mesaconic acid, have been identified and quantified in the urine of a patient with isovaleric acidemia. These compounds do not appear to have been reported previously as being components of human metabolism. In addition, large quantities of 3-methylbutyrolactone, the lactone of 4-hydroxyisovaleric acid, were observed in the volatile profile obtained by headspace chromatography. The demonstration of 4-hydroxyisovaleric acid supports the contention that urinary methylsuccinic acid seen in patients with isovaleric acidemia has arisen by omega-oxidation of isovaleric acid. The identification of mesaconic acid may indicate that the methylsuccinic acid formed in these patients is subject to further metabolism.