Effect of pre - and post-harvest factors on ‘Benny’ Valencia fruit rind phenolics on mitigation of chilling and non-chilling disorders during cold storage

Purpose: This study investigated the effect of harvest time, postharvest dehydration + waxing and storage temperature on rind- free and conjugated phenolics and their ability to alleviate chilling injury and pitting of ‘Benny’ Valencia oranges during cold storage. Research method: Fruit were harvested at early, mid- and late season, and thereafter, divided into control, dehydrated, waxed + dehydrated portions. After treatment, fruit were stored at -0.6 and 4.5°C for 28 days, thereafter, 7 days at ambient temperature (25°C). Findings: In general, peel pitting index (PPI) was significantly higher for late season fruit, while, CI was higher for early season fruit, especially at -0.6°C storage. Furthermore, dehydration stress without waxing resulted in significantly higher PPI and CI at -0.6°C when compared with 4.5°C storage. With respect to both free and soluble conjugated phenolics, the control fruit showed higher levels of rind phenolics, especially at late harvest across all the storage temperatures. Therefore, untreated fruit appeared to tolerate cold stress by up-regulating endogenous systems of total rind phenolics. Postharvest dehydration repressed endogenous phenolics synthesis. In conclusion, susceptibility to pitting disorder increases with harvest time, dehydration stress, while fruit harvested early were highly susceptible to CI. Research limitations: The main limitation of this study is the lack of specific phenolics. Originality/Value: The study found that dehydration plus waxing has a significant effect on chilling and non-chilling citrus ‘Benny’ Valencia fruit. Furthermore, these treatments induced an increase in rind total phenolics to mitigate rind physiological disorders during extended cold storage