Dried Garcinia atroviridis Crude Extracts Incorporated with Gum Arabic Coating Controlled Postharvest Anthracnose Diseases in Dragon Fruits

摘要

The aim of this study was to examine the antifungal effect of dried Garcinia atroviridis fruits extract (GAFE) in combination with gum arabic (GA) against red-fleshed dragon fruits (Hylocereus polyrhizus) anthracnose disease caused by Colletotrichum gloeosporioides as well as to determine the efficiency of dried GAFE in maintaining the postharvest quality of dragon fruits. In vitro results showed that the inhibition in mycelial and conidial growth was dose-dependent and greatest inhibition was recorded at 15 mg/mL dried GAFE+10% GA. Such concentration also conferred fungistatic effects to fungal growth and spore germination in vitro. Concentration at 10 mg/mL dried GAFE+10% GA exhibited similar effectiveness comparable to commercial fungicide (Mancozeb at 3.2 mg/mL) to control anthracnose disease in dragon fruits. In addition, fruits treated with 10 mg/mL dried GAFE+10% GA markedly suppress disease incidence and severity as well as effectively maintained SSC and TA level throughout cold storage. On the other hand, lower dried GAFE concentrations (1 mg/mL and 4 mg/mL dried GAFE+10% GA) suppressed weight loss and retained tissue firmness throughout shelf life of dragon fruits. Coating application at highest concentration of 15 mg/mL dried GAFE+10% GA impaired physicochemical quality by displaying phytotoxic effect on the dragon fruits.