Blood oranges (Citrus sinensis L. Osbeck) are a rich source of phytonutrients and bioactive compounds such as anthocyanins, flavonoids, hydroxycinnamic acids, and ascorbic acid. However, they are very susceptible to cold damage, which deteriorates their quality, and they present a series of symptoms of this when stored at critical temperatures. Storing blood oranges at low temperatures is the main technology used to reduce the respiration rate of the fruit, the development of rot, the loss of water, and other associated physiological processes.
The study of cold damage and how to control it can provide useful knowledge for the postharvest handling of blood orange cultivars to prolong the fruit's life and to maintain the highest quality possible during prolonged cold storage. In recent years, various inducers have been identified whose postharvest application helps to improve the cold tolerance of these oranges during storage.
Postharvest treatment with inducing compounds
In fact, compounds with natural inducers can bring about a series of physiological changes in the treated fruit, as well as the alteration of the mechanisms involved that affect metabolism and increase the synthesis of phytochemical compounds. The researchers from the Department of Agrifood Technology of the Miguel Hernandez University have studied several compounds that act as inducers, such as γ-aminobutyric acid (GABA), methyl jasmonate (MeJA), methyl salicylate (MeSA), and brassinosteroids (BR).
GABA has a role as a cold stress reliever in horticultural crops and therefore has the ability to improve resistance to chilling in fruits during storage.
Postharvest treatment with MeSA can improve the antioxidant system and increase the synthesis of heat shock proteins (HSP), and subsequently reduce cold damage during cold storage. The volatile compound in MeJA is derived from jasmonic acid (JA) and can increase the postharvest life of fruits during cold storage.
Brassinosteroids could have control functions that help improve resistance to postharvest stress.
In conclusion, post-harvest treatment with inducers might be a promising approach to reduce cold damage and improve the storage capacity of blood oranges during cold storage, allowing producers to preserve a high-value product for fresh consumption or processing long after it's been harvested.