Differences in volatile profiles of skin, pericarp, and locular gel of tomato fruit

The aroma of tomato is a determinant for consumer satisfaction. Histology and biochemistry of ripening differ in the placental tissue, pericarp and skin of the tomato fruit. Thus, different proportions of locule and pericarp should influence the aroma of the tomato. The objective of this study was to determine the differences in volatile aroma compounds in the skin, in the outer pericarp and locule of ripe tomato. Tomato (Solanum lycopersicum ‘Valoasis’, F1, Rijk Zwaan) fruit in the red stage were separated into skin, outer pericarp and locular gel without seeds. The volatiles were extracted by SPME, separated by gas chromatography and identified by mass spectrometry. A total of 48 volatile compounds relevant to the aroma were identified. The proportion of skin mass, external pericarp and locule was 12%, 42% and 17%, respectively. A greater number of volatile compounds (32) were identified in the skin than in the pericarp (21) and the locular gel (20). In the skin alcohols predominated, with 7-octen-4-ol, 2-methyl-6-hepten-3-ol and 2,6-dimethyl-3-heptanol being the most prominent. In the pericarp and in the locule predominated the aldehydes [hexanal, 2- hexenal, 3,5-dimethylbenzaldehyde, (E)-2-octenal, (E, E)-2,4-decadienal, (Z)-2-heptenal and (E, E)-2,4-heptadienal]. The locular gel also had a high concentration of ketones, namely 6-methyl-5-heptene-2-one, 3-octanone and 4-octen-3-one, and eugenol, only detected in this tissue. In conclusion, the profile of volatile compounds is distinct in the skin, in the pericarp and in the locular gel of the tomato; fruit morphology and the histological and physiological specificities of the different parts influence the tomato aroma.