Identification of sulphur volatiles and GC-olfactometry aroma profiling in two fresh tomato cultivars

Ten sulphur volatiles were observed in two Florida tomato cultivars ('Tasti-Lee' and 'FL 47') harvested at three maturity stages (breaker, turning, and pink) using gas chromatography with a pulsed flame photometric detector (GC-PFPD). Eight PFPD peaks were identified using retention values from authentic sulphur standards and GC-MS characteristic masses. Seven were quantified using an internal standard combined with external calibration curves. Dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide 2-propylthiazole and 2-s-butylthiazole were newly identified in fresh tomatoes. Principal component analysis of sulphur volatiles indicated that there were appreciable maturity stage differences clustered in separate quadrants. GC-olfactometry (GC-O) identified 50 aroma-active compounds in 'Tasti-Lee', with 10 reported as odorants in fresh tomatoes for the first time. Four sulphur volatiles exhibited aroma activity, including two of the newly-reported fresh tomato sulphur volatiles, 2-s-butylthiazole and dimethyl sulphide. GC-O aroma profiling indicated that the most intense aroma category was earthy-musty, followed by fruity-floral, green-grassy, sweet-candy and sweaty-stale-sulphurous.