Impact of two hot water treatments applied sequentially on oxidative metabolism related to chilling injury tolerance in mango fruit

Abstract

Mango is susceptible to chilling injury (CI). Its short-term exposure to heat treatments can induce tolerance to this disorder; however, a short time is not enough to control the fruit fly. In this sense, the application of sequential heat treatments where the quarantine treatment is included can bring great benefits for mango marketing. The aim of this research was to evaluate the effect of two different sequentially-applied hot water treatments (HWT) on CI tolerance and changes in oxidative metabolism in mango. Mangoes were divided into four groups: control, HWT1 (dipping in water at 46.1 °C for 75 min), HWT2 (dipping in water at 55 °C for 5 min), and HWT1 + HWT2. Fruits were stored at 5 °C/30 days to induce CI and thereafter at 21 °C for 8 days. Three replicates with five repetitions were used to evaluate CI index, electrolyte leakage (EL), malondialdehyde (MDA), weight loss (WL), color, firmness and enzymatic antioxidant activity. The use of HWT1 reduced CI during low temperature storage, while HWT2 and the HWT1 + HWT2 showed lower CI symptoms during ripening. The use of HWT1 showed a similar EL % and higher MDA content (7.07 x 104 nmol·L-1) than the control (6.68 x 104 nmol·L-1). HWT1 + HWT2 showed the lowest WL (2.98 %) and the highest enzymatic antioxidant activity during cold storage and during the first days at 21 °C, while HWT2 showed the highest color and firmness retention. Hot water treatments applied sequentially can be considered an effective alternative to induce CI tolerance and to maintain the quality of mango.