|DU, XIAOFEN - University Of Florida|
|SONG, MEI - University Of Florida|
|Baldwin, Elizabeth - Liz|
|ROUSEFF, RUSSELL - University Of Florida|
Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2014
Publication Date: 3/15/2015
Citation: Du, X., Song, M., Baldwin, E.A., Rouseff, R. 2015. Identification of sulphur volatiles and GC-olfactometry aroma profiling in two fresh tomato cultivars. Food Chemistry. 171:306-314.
Interpretive Summary: Tomato fruit aroma is a combination of around 30 aroma volatiles. Among those is one known sulphur volatile. Sulphur volatiles are difficult to detect by conventional gas chromatography detectors, necessitating a special sulphur flame photometric detector. Using this detector, ten sulphur volatiles were identified and quantified in two tomato varieties at different maturity stages, one a recent release from the University of Florida breeding program (Tasti Lee) and one an industry standard (FL 47). In addition twelve new odorants were identified, including 4 sulphur compounds, for fresh tomato. Gas chromatography-olfactometry (GS-O), where a human nose is used as a detector (sniffing the sample after separation on a GC column) revealed that the most intense aroma category was earthy-musty, followed by fruity-floral, green-grassy, sweet-candy and sweaty-stale-sulphurous. Fresh market tomatoes in the U.S. are reported to have poor flavour due to more earthy-musty green aroma and lack of fruity-floral odors, so information on target aroma volatiles for breeders is useful to improve tomato cultivars.
Technical Abstract: 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-sec-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-O identified 50 aroma-active compounds in ‘Tasti-Lee’, with 12 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-sec-butylthiazole and dimethyl sulphide. GC-O aroma profiling indicated the most intense aroma category was earthy-musty, followed by fruity-floral, green-grassy, sweet-candy and sweaty-stale-sulphurous.