Postharvest UV-C treatment of tomato fruits: Changes in simple sugars and organic acids contents during storage

- The hormetic UV-C dose of 3.7 kJ/m2 was applied to 5 tomato CVs at 2 maturity stages.
- Changes in simple sugars and organic acids were assessed over a 15-d storage period.
- UV-C treated fruits tended to have a lower sugar content and a higher acid titre.
- The changes caused by UV-C would likely not be perceived by a sensory panel.

Tomato fruits of five different cultivars were harvested at two maturity stages subjected to the hormetic UV-C dose of 3.7 kJ/m2, and stored over 15 d. Simple sugars (glucose, fructose, and sucrose) and organic acids (ascorbic, citric, malic, and oxalic) were assessed at harvest and after 10 and 15 d of storage. The sugar content was generally lower in the UV-C-treated fruits, whereas the acid titre tended to be higher. Nonetheless, the higher ratios of total sugars to total organic acids in 'Balzamoth' breaker fruits after 10 d, 'Balzamoth' vine-ripe fruits after 15 d, 'Lorenzo' breaker fruits after 10 d, 'Makari' breaker fruits after 10 d, and 'Makari' vine-ripe fruits after 10 d suggest that UV-C treatment has the potential to improve the taste of those cultivars. Malic acid was the analyte most influenced by UV-C, with higher levels maintained in the breaker fruits of all cultivars, and possibly playing a role in the induction of defence mechanisms. In light of the available literature, it is not likely that the changes reported in this study would be noticed by a sensory panel. Lastly, the higher ascorbic acid found in treated fruits point to the potential of UV-C hormesis to enhance nutritional value without negatively impacting taste attributes.