Effects of bio-based coatings on the ripening and quality attributes of tomato (Solanum lycopersicum) fruits

BACKGROUND: Postharvest conservation of tomatoes is a major current challenge for growers and traders. Edible coatings constitute a pertinent alternative to existing conservation methods. RESULTS: Control tomatoes were fully ripe 3 days after harvesting, whereas fruits dipped in solutions containing extracts from cocoa pods (T1), cocoa leaves (T2) or coffee hulls (T3) reached full ripeness 14 days after treatment (DAT). Fruits treated by dipping in a solution containing an extract from coffee leaves (T4) were fully ripe 21 DAT. The visual assessment was confirmed by alterations in the level of chlorophyll a. Treatments induced a significant inhibition of chlorophyll a breakdown, especially during the first week after their application, T4 being the most efficacious. Weight loss increased significantly throughout the experimental period and was accelerated by treatments. Some quality-related parameters of ripe tomato fruits were in most cases not significantly influenced by treatments. In a few cases, however, there were improvements in quality traits of ripe fruits. On 21 DAT, T4 induced significant increases in levels of β-carotene and 6-methyl-3,5-heptadien-2-ol, whereas T2 led, especially, to higher levels of volatile compounds. CONCLUSION: Edible coatings based on extracts from coffee or cocoa leaves induced improvements in the shelf life and quality of tomato fruits.