Impact of hot water-calcium on the activity of cell wall degrading and antioxidant system enzymes in mango stored at chilling temperature

Mango can develop symptoms of chilling injury (CI) during storage at low temperatures. The application of a hot water treatment (HWT) prior to cold storage can prevent this disorder; however, prolonged exposure to heat may cause accelerated softening of the fruit. Calcium salts allow the formation of pectates delaying softening and in combination with HWT can reduce the susceptibility to CI. This study evaluated the effect of the quarantine HWT (46.1°C, 75-90 min), calcium lactate (CaLac, 0.05%), and their combination (HWT-CaLac) on the activity of cell wall and antioxidant system enzymes in "Keitt" mango stored for 20 days (5°C) and during ripening (21°C). HWT and HWT-CaLac reduced CI sensitivity while the combination was more effective to reduce cell wall enzymatic activity and to increase the activity of the antioxidant system enzymes in mango, this demonstrated the usefulness of a HWT-CaLac combination to extend mango storage life by inducing CI tolerance. PRACTICAL APPLICATIONS: Simultaneous application of treatments in diverse crops is significant for prevention of rapid deterioration. In this study, the application of calcium lactate in an established quarantine hot water treatment for mango fruit fly reduced chilling injury presence and stimulated the antioxidant defense mechanism. In this sense, producers and packers can take advantage of this procedure to prolong the storage period of the fruit preserving its postharvest quality and minimizing the risk of chilling injury presence.

Keywords: calcium lactate; chilling injury; enzymatic activity; hot water; mango.