BIOPOLYMERS AND BIOACTIVE COMPOUNDS AS ALTERNATIVES FOR THE CONTROL OF ANTHRACNOSE IN POSTHARVEST MANGOES

Anthracnose, caused by Colletotrichum gloeosporioides, is one of the main postharvest diseases of mangoes, affecting fruit quality, commercial value, and market acceptance. In addition to the economic losses associated with fruit decay, the presence of lesions makes export to demanding markets, such as the European Union, nonviable due to strict limits on pesticide residues. Chemical control, although effective, faces challenges related to environmental risks and trade barriers. In this context, this study aimed to evaluate the antifungal activity in vitro of formulations based on chitosan (Q) and carnauba wax microemulsion (C), combined with cinnamaldehyde (C) and thymol (T), against the growth of C. gloeosporioides, as a sustainable alternative for mango disease control. Four treatments (QC, QT, CC, and CT), resulting from the combination of matrices with compounds, were tested at four concentrations and five replicates each, defined from preliminary tests: 0.1, 0.25, 0.5, and 1.0% for QT and CT; 2.0, 3.0, 4.0, and 5.0% for QC; and 4.5, 5.0, 5.5, and 6.0% for CC. The tests were conducted using the agar dilution method in potato-dextrose-agar (PDA) medium. For inoculation, a mycelial plug of the fungus was placed in the center of the plates, which were incubated at 25 °C until the control colony covered the entire surface of the medium. Mycelial growth was measured (mm) in two perpendicular directions using a digital caliper, and the inhibition percentage was calculated by the formula PI (%) = (Control Growth – Treatment Growth / Control Growth) × 100. Treatments containing thymol (CT and QT) showed the highest effectiveness, obtaining 97% and 87% inhibition of fungal growth at concentrations of 0.5% and 1.0%, respectively. QC obtained complete inhibition at concentrations ≥ 5.0%, while CC was effective from 6.0%. These findings indicate that the tested biopolymers and compounds are promising strategies to reduce postharvest losses and meet food safety and competitiveness demands in a sustainable manner. Thymol’s performance is noteworthy, as its hydrophobic nature enables interaction with fungal membranes and interference with essential biosynthetic and signaling pathways, making it a potent antifungal agent. The results obtained will serve to support the continuation of the research, with in vivo, postharvest and sensory analyses.