Effects of hot air treatment on postharvest quality of ‘cat Hoa loc’ mangoes

Abstract

Effects of hot air treatment on postharvest quality of 'cat Hoa loc' mangoes. Abstract — Introduction. Vietnam is among the world's top 20 mango producing countries. In this country, the 'cat Hoa loc' variety is predominant, with 17 692 ha under cultivation with an annual produc- tion of 58 471 t; it is considered to be the best mango variety in the Mekong delta. Ripening of the fruit is typically expressed by a skin colour change from green to bright yellow. This variety is highly prized by local and foreign consumers, but subject to different disorders, especially fruit fly infestations. Heat treat- ment is a safe alternative to chemical treatments. It can impair mould development and control fruit infes- tation by destroying fruit fly eggs and larvae. It may have a greater or lesser effect on fruit physiology. If the treatment temperature and duration are incorrectly handled, skin burns may result and the internal qua- lity of the fruit may be affected. Materials and methods. 'Cat Hoa loc' mangoes at the commercially mature stage were subjected to hot air treatment (47 °C and 90% RH) of different durations ((0, 20, 40, 60, 90, 120 and 180) min from the fruit core attaining the temperature). After treatment, the fruits were stored at 25 °C and quality parameters evaluated (weight loss, peel and flesh colour, percentages of fruit with burns and rots, burn index, ripening percentage, firmness, TSS, TA, vitamin C content, pH, reducing and total sugars, and taste test). Results and discussion. For the 'cat Hoa loc' variety, heat treatment accele- rated ripening of the fruit in the initial storage period and colour changes occurred more quickly. However, after 7 days' storage, the difference in Hue value between the treated and control fruits disappeared. Hot air treatment at 47 °C of different durations ((20 to180) min) did not affect the internal coloration changes of 'cat Hoa loc' mangoes, but did affect the flesh firmness. We found that, after 3 d, hot air treatment at 47 °C led to significantly faster weight loss than control fruits but this difference disappeared after 7 d. Total sugar content was not affected by the treatment, but titratable acidity decreased more quickly in treated fruits. Vietnam /Mangifera indica/ fruits / postharvest control / heat treatment / quality