Compositional analysis of cashew (Anacardium occidentale L.) peduncle bagasse ash and its in vitro antifungal activity against Fusarium species

Abstract

Cashew (Anacardium occidentale L.) is a plant with a highly social and economic importance in the Northeast Region of Brazil. Cashew peduncle bagasse is one of the greatest sources of residues (90–94%) produced by the cashew agronomic industry. In this study, we prepared cashew peduncle bagasse ash and submitted it to compositional analysis and in vitro tests for antifungal activity against Fusarium species. This analysis indicated a crystallinity of around 73%, corresponding to the following soluble phases: potassium bicarbonate - KHCO3 (39.54%), potassium sulfate - K2SO4 (24.87%), and struvite-K - MgKPO4·6H2O (8.59%). The amorphous phases (around 27%) were identified as the insoluble fraction of the ash. The solution showed high antifungal activity against F. oxysporum, F. moniliforme and F. lateritium. The activity of this product was greater than that of Cercobin® (thiophanate-methyl), indicating that this material could possibly be used as a non-toxic antifungal agent.