Search

Tarocco "Sant'Alfio" is a late ripening blood orange cultivar. Blood oranges are more and more appreciated from consumers for their high nutraceutical value due to the presence of bioactive compounds including vitamin C, polyphenols, flavonoids and hydroxycinnamic acids. The aim of this work is to set up a reliable protocol for postharvest storage of the very-late Tarocco "Sant'Alfio" orange to prolong the availability of this product in the market to be used for fresh chilled orange juice production. Fruits were subjected to three storage treatments (20days at 1°C plus 50days at 4°C; 70days at 4°C; 70days at 20°C). The results indicate that cold treatments, in particular at 4°C constantly, can extend Tarocco "Sant'Alfio" shelf life enhancing total anthocyanin content. The defined protocols allow prolonging market availability of a high value product and could induce relevant benefits for the citrus industry and consumers., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The health benefits associated with the consumption of anthocyanin-containing foods are extensively documented. Mature fruits of blood oranges and their hybrids are characterized by the presence of these bioactive pigments, the abundance of which can be enhanced by storing fruit at cooling nonfreezing temperature. In this work the effects of short low-temperature exposure (4 °C × 15 days) upon orange anthocyanin content and the expression of structural genes belonging to the pigment biosynthesis pathway were investigated. The results highlight that anthocyanin levels of fruit exposed to cold sharply increase, reaching, after 6 days of storage, a value 8 times higher than that observed in the time zero samples, thus suggesting that fruit with enhanced health-related attributes might be obtained at this storage stage. The analysis of gene expression shows that the amount of transcripts of all considered genes (CM1, PAL, CHS, DFR, ANS, UFGT, and GST) sharply increased after 3-6 days of cold storage, confirming previous data showing that the biosynthesis of anthocyanins is a cold-regulated pathway. By comparing the expression of selected genes (PAL, DFR, and UFGT) between blood and common oranges, it turns out that those genes strictly involved in anthocyanin biosynthesis are not cold responsive in common oranges. Moreover, the data highlight that the EST encoding the transcription factor NAC domain protein is selectively induced by cold in blood oranges but not in common oranges, thus proposing it as a candidate gene specifically involved in blood orange response to cold exposure.