The Aroma Components in Fruits and Vegetables

Part V. The volatiles of watermelon (Citrullus vulgaris)

Abstract

Volatiles in fresh watermelon fruit (Citrullus vulgaris) were analyzed by gas chromatography and thin layer chromatography. The volatiles for this analysis were collected by vacuum distillation, and concentrated by ethyl chloride extraction method.
When the column of PEG 1500 was used, the gas chromatograms indicated the presence of 58 components, of which 26 were identified tentatively, and 17 were corresponded with the assumed substances by the another gas chromatography employing Tween 60. When aqueous distillate was treated with 2, 4-dinitrophenylhydrazine, peak numbers of the gas chromatograms reduced to 49, that is 9 peaks (probably carbonyls) were removed from initial gas chromatograms. However, only 7 spots were found in thin layer chromatography of carbonyl 2, 4-dinitrophenylhydrazones, and spectrophotometrical analysis of the spots suggested the presence of three 2-alkanones and four n-alkanals.
Significant differences were found in volatile patterns between flesh and peel of watermelon. The large amount of 3 components in higher boiling point fraction were contained in the flesh, on the contrary, in the peel, large amount of 5 or 6 components in lower boiling point fraction were contained.