Abstract

The potential of chitosan (unirradiated and irradiated) to be used as an antifungal agent to reduce anthracnose disease on banana var. embul and thereby to improve its shelf life was investigated. Chitosan was irradiated using gamma radiation and a low dose of 5 kGy was used to determine the potential of using lower doses to irradiate chitosan in antifungal treatments. Minimum inhibitory concentration (MIC) of chitosan against Colletotricum musae was determined via a series of experiments on potato dextrose agar. A complete inhibition of C. musae was observed at chitosan concentrations ≥ 0.30% (irradiated) and chitosan concentrations ≥ 0.75% (unirradiated). In-vivo treatments showed 100% disease control when applied chitosan formulations ≥ 1.0% (irradiated) and chitosan formulations ≥ 1.5% (unirradiated) on fresh banana. Chitosan treatments had no adverse effects on the organoleptic and physiological properties of the fruit. Favorable changes were observed in chitosan treated banana with respect to firmness and weight loss. Overall acceptability of the chitosan treated banana was 70%. Irradiated chitosan is more effective than unirradiated chitosan in controlling the anthracnose pathogen and anthracnose disease. Irradiation has enhanced the antifungal activity of chitosan and a low dose such as 5 kGy was sufficient to increase the antifungal activity of chitosan against C. musae.