Flavor chemistry often has been equated with the analysis of volatile compounds using gas chromatography combined with fast-scan mass spectrometry, but this view is too restrictive as an extensive array of methods has evolved for the analysis of flavor compounds. The identification of flavor-active compounds and associated precursor substances is a primary goal of flavor analysis, but accurate measurement of concentrations of these compounds in foods is an equally important goal. Sensory assessments of flavor compounds and foods are essential for achieving objectives of flavor investigations regardless of ultimate goals. Isohumulone is the precursor for the compound that causes the sunstruck or skunky flavor in beer exposed to light. National policies encouraging reduction in sodium consumption have stimulated interest in foods in which sodium salts have been replaced by alternative substances, particularly those containing potassium and ammonium ions. The fresh flavors of disrupted tissues are caused mainly by isothiocyanates resulting from the action of glucosinolates on thioglycoside precursors.