Abscisic acid and carotenoids metabolism in tomato during postharvest

Tomato is one of the most consumed vegetables in the world. Carotenoids are largely appreciated health-related compounds in tomato fruit and are recognized as bioactive substances with powerful antioxidant activity. Lycopene and β-carotene (vitamin A) are the most abundant carotenoids accumulated in the fruit. In the last few years, several studies were carried out on carotenoids focusing on their cleavage products, in particular to abscisic acid (ABA). ABA plays important roles in plants, including regulation of plant growth and development, seed and bud dormancy, apical dominance, senescence abscission and stress responses in both plant and postharvest. In this work we aimed to study ABA metabolic pathway and its related metabolites in the cultivar ‘Ailsa Craig’. Tomatoes were grown under controlled conditions, then fully ripen fruits were collected and maintained at 20°C for two weeks in order to evaluate quality changes during a shelf life period. During shelf life, colour changes, lycopene, β-carotene, ABA, volatile organic compounds (VOCs) from direct headspace GC-MS analyses were evaluated. Lycopene and β-carotene increased during shelf life. The analysis of VOCs allowed identifying the most abundant compounds and changes on the postharvest storage at 20°C. During storage, the 3-methyl butanal, pentanal, 3-methyl-1-butanol and 2-carene, were no longer detectable, while heptane, which was not present at harvest was detected. Moreover, an unknown compound, was detected only at 7 and 14 days of storage.