Giacomo Cocetta1 et al., VIII International Postharvest Symposium
Tomato is one of the most consumed vegetables in the world. During the last 20 years, tomato production, as well as the area dedicated to its cultivation, has doubled.
Carotenoids are among the most 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.
The most innovative studies carried out in the last few years on carotenoids were focused on their cleavage products and 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 a transformed line of tomato (cv. Ailsa Craig) overexpressing the NCED gene (the key gene in ABA biosynthesis) in fully ripe fruit was developed. Plants were grown under controlled conditions, then fully ripe fruits were collected and maintained at 20ºC and 50-60% relative humidity (RH) for two weeks in order to evaluate quality changes during a shelf life period.
At harvest the levels of ABA and the expression of the key genes in the ABA biosynthetic pathway were measured and compared to non-transformed control plants. During shelf life, the effects of the transformation were evaluated through a combined approach consisting in the HPLC-DAD analysis of carotenoids, analysis of volatile organic compounds (VOCs) from direct head space GC-MS analyses, analysis of ABA levels and determination of changes in skin color.
HPLC analyses revealed some significant changes in carotenoids levels observed at harvest and during shelf life for the different lines studied. Consistently, parallel changes in the color were observed as well.
The analysis of VOCs allowed identifying the most abundant compounds responsible for the characteristic aromatic profile of tomato fruits and to determine changes depending on the NCED overexpression and on the postharvest storage at 20ºC.
Abscisic acid and carotenoid metabolism in tomato during postharvest
Giacomo Cocetta1, Alice Trivellini2, Giulia Franzoni1, Sergio Angeli3, Antonio Ferrante1
1 Dept. Agricultural and Environmental Sci., via Celoria 2, 20133 Milano, Italy
2 SSSA, Piazza Martiri della Libertà 33, 56100 Pisa, Italy
3 Faculty of Science and Technology, Piazza Università 5, 39100 Bolzano, Italy
VIII International Postharvest Symposium, Cartagena, Spain, 21-24 June 2016