Volatile organic compounds as potential markers for kiwifruit storage breakdown (SBD)

New yellow-fleshed kiwifruit cultivars (Actinidia chinensis var. chinensis) have been developed in the last 20 years, some of them gaining an important share of the market. Due to the rise in the demand of yellow-fleshed kiwifruit, having a year-long kiwifruit distribution is a crucial goal. Postharvest losses related to softening and storage breakdown (SBD) are the major challenges to achieve this goal. SBD is associated with the ripening of kiwifruit at cold storage temperature that may depend on several aspects, such as the preharvest factors, fruit maturity level at harvest, the rate at which fruit are precooled, and storage conditions. SBD develops as water-soaked area of tissue that will progressively occupy more of the inner pericarp and eventually move to the outer pericarp. Symptoms will continue to express as fruit ripen. During ripening fruit emit a complex blend of volatile organic compounds (VOCs) which contribute to their aroma. Physiological disorders may change VOCs emission and, therefore, it could be used to detect chilling injuries or disorder before their onset. Furthermore, some of these VOCs may also contribute to the development of symptomatology. Our study aimed at i) determining the risk of SBD and softening incidence in relation to fruit maturation at harvest, ii) characterizing VOCs emission by healthy and SBD affected kiwifruit to identify possible VOCs markers to be used for early detection of this disorder to minimize losses. The evolution of kiwifruit VOCs emission was studied by Proton Transfer Reaction - Time of Flight - Mass Spectrometer (PTR-ToF-MS). Our results show that different VOCs masses are emitted in SBD-affected fruit and their concentration increased with the severity of symptoms. These evidences suggest that VOCs monitoring could be a promising tool for an early diagnosis of SBD