Effects of Delayed Precooling on the Postharvest Quality and Anthracnose Incidence of “Irwin” Mangoes

Abstract

Mangoes are typical climacteric tropical fruits with accelerated metabolism, degradation, and senescence after harvest due to the accumulation of field heat. Thus, removing field heat as soon as possible after harvest is essential. In addition, a severe postharvest disease of mango, anthracnose, has been reported to be caused by Colletotrichum gloeosporioides, thus decreasing the shelf life and limiting mango export. This study was performed to investigate the effect of delayed precooling on the quality and incidence of anthracnose during storage of Irwin mango at different operational times after the harvest. Therefore, in this study, Irwin was precooled for 30 min at 3, 6, 12, and 24 h postharvest and immediately stored in a cold room at 5°C. The appearance, anthracnose incidence, respiration rate, ethylene production, firmness, total soluble solids (TSS), titratable acidity (TA), and fruit overripening rate were monitored throughout the shelf life. Early precooling was found to delay anthracnose incidence during the shelf life. Furthermore, the fruit respiration rate during the shelf life was negatively correlated with the precooling delay. The respiration rate of fruits precooled for 3 h after harvest was 8.08 mg CO2 kg–1 h–1 and retained a good appearance throughout the shelf life. Their ripening, reduced firmness, and TA were significantly delayed compared with those of fruits with longer precooling delays, which had a firmness of 19 N, TA of 0.29%, and TSS of 12.6°Brix after 30 d of storage at 5°C, while subsequent warming to 20°C for 3 d, the rate of overripening was significantly lower in fruits with precooling delays of 3 and 6 h than in fruits with a precooling delay of 24 h. Thus, precooling mangoes within 3–6 h of harvest will reduce their respiration rate, delay ripening, decrease anthracnose incidence, preserve quality, and prolong storage life.