Quality and Decay of Irradiated Mangos

Abstract

Abstract Mangos (Mangifera indica L. cvs. Tommy Atkins and Keitt) irradiated with γ-rays from 60Co at dosages of 150 to 1500 Gy, then held for 3 days at 13°C followed by ripening at 24°, developed less ripe peel color than unirradiated mangos. Ripening of ‘Tommy Atkins’ mangos was delayed for 2 to 3 days by 150 and 250 Gy, unaffected by 500 and 750 Gy, and accelerated by 1500 Gy. The pH of juice from ‘Tommy Atkins’ mangos decreased and titratable acidity increased as irradiation dosage increased; soluble solids content was not affected by irradiation. Scald-like peel injury increased with dosage, especially at 500 Gy or higher. Internal breakdown was localized and slight, but its incidence in ‘Tommy Atkins’ mangos was increased at 250 Gy or higher. Hollow pockets in the flesh and flesh darkening were significantly increased by irradiation at 1500 Gy, but not 750 Gy. Severity of anthracnose, caused by Colletotrichum gloeosporioides Penz., was reduced in ‘Keitt’ mangos at 500 Gy and higher. The severity of stem-end rot, caused by Diplodia natalensis P. Evans or Phomopsis citri Fawc., was reduced in ‘Tommy Atkins’ mongos at 1500 Gy, but not 750 Gy. The overall percentage of decayed fruit was reduced by irradiation at 750 Gy or higher. The results suggest that if irradiation is used for insect control on mangos, dosages of 250 Gy and above should be avoided to minimize injury.