Cassava starch coatings for postharvest control of papaya anthracnose

Abstract

The effects of coating papaya fruit (Carica papaya) with cassava starch were studied, to determine the best concentration and mode of action of this material in postharvest control of anthracnose. The concentrations of starch tested were 1%, 2%, 3% and 4%. These were prepared to give gel consistency. Surface sterilized papaya fruits were inoculated with conidia of Colletotrichum gloeosporioides and incubated for 48 h in a moisture chamber. The were then treated with cassava fruit gels and dried. During the following 14 d storage period, fruit maturation and anthracnose on the fruits were assessed, and electron microscopy was used to examine fruit epicarps. All cassava starch coating concentrations reduced fruit maturation and anthracnose, with the 2%, 3% or 4% coatings giving 100% disease control. The 2% starch coating is likely to be optimum, considering the lower cost efficiency of disease control. The mechanism of disease control provided by the coating is likely to be related to delay of ripening and the formation of a protective layer over the fruit.