Effect of Forced, Hot-Air Treatment of Papaya Fruit on Fruit Quality and Incidence of Postharvest Diseases

Abstract

Forced, hot-air (48.5°C for 3-4 h) treatment of pawpaw fruit (Carica papaya), a recently developed quarantine treatment for fruit flies, did not significantly reduce incidences of postharvest diseases compared with fungicide or hot-water treatments. However, when hot-air treatment was combined with thiabendazole (TBZ) (4 g a.i./litre) application or hot-water immersion (49° for 20 min), the incidence of most postharvest diseases was reduced, including those caused by Phomopsis sp., Botryodiplodia theobromae and Mycosphaerella sp. Although disease incidences were not significantly affected by the sequence of hot-air or hot-water application, degreening (lack of surface ripening), along with pitting and scalding symptoms significantly (P<0.01) increased when hot-water preceded hot-air treatment, but these symptoms did not occur when hot-air preceded hot-water treatment. The hot-air treatment was associated with an increase in the incidence of internal lumpiness (hardened lumps of flesh in ripe fruit) compared with untreated fruit.