Physiological responses, nutritional quality and aroma volatiles of the red-fleshed kirkwood navel and ruby valencia oranges during postharvest cold storage

This study evaluates the postharvest performance and responses of the red-fleshed Kirkwood Navel and Ruby Valencia oranges to cold storage (28 d at 2 degrees C) and shelf-life (5 d at 20 degrees C) in comparison with the standard varieties Washington Navel and Valencia late, respectively. Fruit of Kirkwood and Ruby exhibited lower chilling injury than the reference varieties while maintained similar weight loss and peel firmness. Moreover, the large concentration and the original composition of carotenoids in the pulp of Kirkwood and Ruby was preserved during the postharvest storage. Similarly, the content of vitamin C, phenolics and flavonoids, and the higher lipophilic antioxidant capacity and the capacity to quench singlet oxygen of the red-fleshed oranges remained unaltered after the whole storage period. The content of other compounds as tocopherols and sugars increased at the end of the storage period in fruit of the red-fleshed varieties. Monoterpenes, norisoprenoids, ethanol, alde-hydes and ethyl esters were the compounds that exhibited the major changes during the postharvest storage, especially in the red-fleshed varieties. The profile of volatile compounds of Kirkwood and Ruby fruit was characterized by higher levels of norisoprenoids, monoterpenes, long-chain aldehydes, and variable content of aliphatic esters compared to the reference varieties. Altogether, our results indicated that Kirkwood Navel and Ruby Valencia oranges show good postharvest performance and potential for long-term cold storage, ensuring their quality and retaining their enhanced properties and added value to consumers. Data availability: All data are available in the manuscript or supplementary materials.

Automated summary

This study evaluates the postharvest performance and responses of the red-fleshed Kirkwood Navel and Ruby Valencia oranges to cold storage and shelf-life. The results showed that Kirkwood and Ruby exhibited lower chilling injury, maintained similar weight loss and peel firmness, and preserved the concentration and original composition of carotenoids, as well as the content of vitamin C, phenolics and flavonoids. The red-fleshed oranges also showed increased content of tocopherols and sugars, and major changes in volatile compounds during the postharvest storage.