Ripening associated phytochemical changes in mangos (Mangifera indica) following thermal quarantine and low-temperature storage

Fresh mangos entering the United States must be subjected to a thermal quarantine treatment to eliminate invasive pests, commonly followed by cold storage to extend shelf-life. Changes in phytochemicals and their resultant antioxidant capacity after such treatments are unknown. These studies evaluated mature, green mangos subjected to a simulated quarantine treatment using hot water immersion at 50 degrees C for 60 min and subsequent storage at 5 degrees C and 20 degrees C against their respective controls. Fruit held at 5 degrees C were transferred to 20 degrees C after 8 d of storage to complete ripening, whereby symptoms of chill injury were observed. Phytochemical, antioxidant capacity, and quality parameters were then assessed every 4 d as the fruit ripened over the next 20 d. Storage temperature during ripening and not the hot water treatment was the major factor contributing to changes in polyphenolic content, with antioxidant capacity unaffected by either postharvest treatments or ripening. Major polyphenolics identified were free gallic acid and 4 gallotannins that collectively increased in concentration by 34% as the fruit ripened, also independent of postharvest and storage treatments. Carotenoid concentrations were highest in hot water-treated fruit stored at 20 degrees C, whereas storage at 5 degrees C initially delayed ripening. Despite appreciable differences in fruit quality during quarantine treatment or low temperature storage, only minor differences in antioxidant phytochemicals were observed.