Sulfur-containing acids and esters of white asparagus (Asparagus officinalis) were enriched by liquid-liquid extraction with pentane-methylene chloride (2:1), separated by means of LSC on silica gel and preparative GLC and investigated by capillary gas chromatography-mass spectrometry. Besides 1,2-dithiolane-4-carboxylic acid (asparagusic acid), its methyl and ethyl esters, 3-mercaptoisobutyric acid, 3-methylthioisobutyric acid, diisobutyric acid disulfide, and 3-S-acetylthiomethacrylic acid were identified as intracellular constituents. The biosynthesis of asparagusic acid was assayed with I4C-labeled precursors and asparagus tissue discs. ['4C]-~-Valine was transformed via oxo acid, isobutyrate, methacrylate into 3-methylthioisobutyrate and to a lesser extent into asparagusic acid.

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Volatile phenolic compounds of beer, wort, smoked beer, and sherry were enriched, separated, identified, and quantified by means of the methods of column chromatography, gas chromatography, and mass spectrometry. The analyzed foods are significantly varying in the composition and quantity of the phenolic components. Four origins of phenolics in food are shown by these results.