Evolution of volatile compounds in 'Cuoredolce®' and 'Rugby' mini- watermelons (Citrullus lanatus (Thunb.) Matsumura & Nakai) in relation to the ripening degree at harvest.

Watermelon is appreciated for its nutritional properties and for its flavour. Among flavour active compounds, volatiles play a key role being responsible for aroma. Recent breeding activity has led to the release of mini-watermelons with reduced fruit weight. This paper reports on the characterization of aroma profiles of 'Rugby' and 'Cuoredolce®' novel mini-watermelon cultivars in function of the ripening stage. The main volatiles were identified and quantified using HS-SPME-GC-MS, and their concentrations were correlated to the E-nose profile. The potential contribution of volatile compounds to the fruit aroma was evaluated computing the Odour Activity Values (OAV).Twenty main volatile compounds were identified: aldehydes (9), alcohols (4), ketones (2), and terpenes and terpenoids (5). C-9 aldehydes and alcohols were the prevalent compounds. The two cultivars resulted different in precocity and 'Rugby' was nearer to full ripeness from the early stage considered. Many apocarotenoids with desirable olfactory notes were detected in the volatile profile of 'Rugby'. Four E-nose sensors' signals significantly changed with variety and ripening stage: W1W and W2W were positively and W6S negatively correlated with all identified volatiles, while W3S showed a negative correlation with 6-methyl-5-hepten-2-one, the major lycopene catabolite.The described aroma profiles contribute to the characterization of 'Cuoredolce®' and 'Rugby' mini-watermelon cultivars. E-nose measurement was able to discriminate between cultivars and, at a lower extent, among ripening stages. This article is protected by copyright. All rights reserved.