Preharvest salicylic acid and chitosan treatments reduce red drupelet reversion and enhance antioxidant capacity in blackberry fruit

Red drupelet reversion (RDR) is a postharvest physiological disorder affecting fresh blackberries during commercialization. The drupelets revert from fully black to red, causing detriments of the commercial value. The specific mechanism is still being investigated, some reports suggest that the occurrence of RDR is associated with pigment degradation in the fruit, and can be caused or aggravated by mechanical damage and storage conditions. Even, though studies report no significant alteration in blackberry organoleptic properties caused by RDR, the visual aspect of it affects the consumer perception of the fruit quality reducing marketability and ultimately generating economic losses. In this regard, preharvest treatments have been recently reported to have positive effects in reducing RDR in blackberries. In this study, we investigated the effects of chitosan (COS) and salicylic acid (SA) as preharvest treatments on the phenolic compound content and antioxidant capacity of blackberry fruit. The results showed that SA 3 mM and COS 0.25% treatments increased the total phenolic and flavonoid content while also enhancing the antioxidant capacity of blackberries. We also observed that the content of specialized metabolites and the activity of antioxidant enzymes have a negative correlation with the occurrence of RDR in blackberries.