Abstract:
High postharvest losses occur in bananas due to the banana anthracnose disease. Application of
cinnamon oil against the banana anthracnose pathogen is an effective solution for the postharvest
losses. The volatile antifungal properties of cinnamon oil were evaluated against Colletotrichum
musae, the causal agent of banana anthracnose disease under in vitro and in vivo conditions. The
pathogen was isolated from infected banana fruits and cultured on potato dextrose agar (PDA).
The antifungal efficacy of cinnamon oils on C. musae was evaluated in vitro using a series of
volumes of the oils (0.1 – 4.4μl/cm3), using a culture chamber method. The in vitro test revealed
that 0.1μl/cm3 level was sufficient to suppress the mycelia growth and spore germination of C.
musae. For the in vivo evaluation, artificially inoculated banana fruits at the ripening stage were
exposed to 25%, 50% and 100% concentrations of cinnamon leaf oil and bark oil (0.1 μl/cm3) at
room temperature (27 oC) under ambient light to evaluate the anthracnose lesion development
on the fruit surfaces. Average diameters of the lesions were recorded in 12 and 14 days after
treatments. The minimum level to achieve significant lesion inhibition (p < 0.005) without
damaging the fruit peel was the 50% concentration of cinnamon bark oil. Physical, chemical
properties and organoleptic properties of the treated banana were evaluated along with the
untreated fruits to assess their eating quality. The oil treatments did not significantly change the
organoleptic properties of Cavendish banana except the taste, in which the leaf oil treated sample
received less score. Fruit firmness of cinnamon bark oil and leaf oil treated banana samples were
3.44 N and 1.46 N, respectively compared to the control (3.2 N) (p < 0.005). The pH and titratable
acidity of bark oil and leaf oil were 6.08, 5.72 and 1.50%, 0.99%, respectively (p < 0.005). The total
soluble solid content of leaf oil treated sample was 22.90 % of Brix while that of bark oil was
26.40% of Brix. It was concluded that, among the treatments used Cavendish banana exposed to
50% cinnamon bark oil is the most effective for the control of banana disease without
compromising fruit quality parameters under the tested conditions.
