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.