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The aromas of fruits, flowers, herbs, and spices perceptably change following picking of the plant part because the plant part is then, in effect, biologically dead. By collection and analysis of the headspace volatiles over various living and picked flowers, fruits, herbs, and spices the differences in the aroma profiles are traceable to quantitative differences in key volatile components. In addition, the same analytical technique permits the comparison of day vs. night volatile profiles for selected flowers and of various flower colors among the same family. The commercial application of this noble technology is also discussed.

The aromas of fruits, flowers, herbs, and spices perceptably change following picking of the plant part because the plant part is then, in effect, biologically dead. By collection and analysis of the headspace volatiles over various living and picked flowers, fruits, herbs, and spices the differences in the aroma profiles are traceable to quantitative differences in key volatile components. In addition, the same analytical technique permits the comparison of day vs. night volatile profiles for selected flowers and of various flower colors among the same family. The commercial application of this noble technology is also discussed.

Twenty-one mono-carbonyl compounds were identified in a reverted but not rancid soybean oil with a peroxide number of 2.7 meq/kg and a flavor score of 6.0. Six of the carbonyl compounds were saturated methyl ketones, ten were saturated aldehydes and five were 2-enals. The amount of 2,4-dienals in the reverted soybean oil was too small to be fractionated and identified. One fraction of the 2,4-dinitrophenylhydrazones of mono-carbonyl compounds obtained was different in chemical properties from those of the four known classes of compounds; viz. saturated aldehydes, saturated ketones, 2-enals, and 2,4-dienals. The chemical identity of this fraction has not been completely established.

Two distinct types of hydrogenation flavor may originate from catalytic hydrogenation of fats and oils. One is the characteristic flavor developed during hydrogenation. After it is removed by deodorization, the second type of hydrogenation flavor may develop during the storage of the bland deodorized hydrogenated fat.

The gas chromatogram of the isolated volatile by-products I, which were produced during catalytic hydrogenation of soybean oil is quite different from that of the isolated volatile byproducts II, which were produced by a duplicate sample of the same oil subjected to the same conditions of hydrogenation with no nickel catalyst. Many of the peaks on these two gas chromatograms had different retention times. Furthermore, catalytic hydrogenation of I did not alter its gas chromatogram to equal that of II. The side reactions which may take place when an oil is treated under hydrogenation conditions are, therefore, affected by the presence of nickel catalys.

SUMMARY— 2-Pentyl furan is identified as a component of the volatile decomposition products of slightly autoxidized soybean and cottonseed oils and those of thermal oxidation of corn oil and hydrogenated cottonseed oil. The flavor threshold of this compound in oil at room temperature is 1 ppm. At concentrations of 1-10 ppm, it imparts to the oil a characteristic beany odor and flavor reminiscent of those of a reverted soybean oil. Expert organoleptic panels consistently identified a deodorized cottonseed oil containing 5 ppm of 2.pentyl furan as a reverted soybean oil. It is proposed that this compound is formed by autoxidation of linoleic acid.