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Causes of flesh browning in persimmon ‒ a review

Besada, C., Novillo, P., Navarro, P., Salvador, A.
Acta horticulturae 2018 no.1195 pp. 203-210
air, anaerobic conditions, carbon dioxide, chilling injury, cultivars, discoloration, fruits, heat treatment, mechanical damage, modified atmosphere packaging, oxidation, persimmons, shelf life, tannins, temperature
Flesh browning is one of the main physiological disorders that cause important quality losses during the postharvest life of persimmons. Different types of flesh browning have been described, since the manifestation of this disorder can be associated with different causes. In some cases, the appearance of the browning disorder can give us clues to the cause; however in other cases different factors may lead to visually similar browning disorders. Mechanical damage is one of the reported factors involved in flesh browning and persimmons are generally very sensitive to mechanical damages, which may exhibit brown or pinkish areas around the flesh. The mechanism of this alteration has been studied in depth, and the oxidation of tannins has been reported as a key process. Other factors frequently associated with internal browning is storage under controlled or modified atmospheres; in this case the flesh browning occurs mainly in the flesh of the fruit. The optimum atmosphere conditions to prolong storage will depend on the cultivar; thus the same atmosphere can be effective for one cultivar and lead to disorders in other one. Also, exposure to anaerobic conditions, such as those of the CO2-deastringency treatment, may result also in flesh browning when the CO2-exposure is prolonged. Finally, other factor associated with internal browning is high or low temperature exposure. On one hand, the application of heat treatments such as hot water or hot air can cause damage and discoloration in the fruit. On the other, although the main manifestation of chilling injury in persimmon is associated with textural changes, in some cases it has been also related to internal browning.