EFFECTS OF STORAGE CONDITIONS, BOTANICAL ASH AND GREENSYNTHESIZED NANOPARTICLE TREATMENTS ON WATER ACTIVITY, MOISTURE CONTENT AND MOULD DEVELOPMENT IN STORED COCOA BEANS VARIETIES

Abstract

Cocoa bean quality is strongly influenced during storage, by environmental conditions that can promote fungal contamination and compromise product safety. This study investigated the effects of storage conditions on water activity, moisture content and mould development in dried fermented cocoa beans varieties in Nigeria. Freshly fermented and dried F3 Amazon and CRIN Tc cocoa beans varieties were separately treated with ash and green-synthesized silver nanoparticles forms of neem and scent leaf botanicals at different concentrations and  copper sulphate (positive control), and stored for 120 days at 29–34 °C (under 55–65% RH) and 29–31 °C (under 85–95% RH). Moisture content and water activity were determined at the beginning and end of storage using standard procedures, while mould development was assessed at the end of the storage period. Results showed that cocoa beans stored under high humidity conditions exhibited higher moisture content (5.21 -12.09%), water activity values (0.59 – 0.73), and higher mouldiness (up to 100%), indicating strong influence of environmental humidity on moisture dynamics and mould development during storage. Positive moisture content/water activity correlations (0.369 – 0.822) were observed in both cocoa varieties, implying close relationship. Mould development ranged between 60% and 100% across treatments, with untreated control samples showing the highest levels of mouldiness. Findings from this study demonstrated that elevated moisture favoured higher water activity and fungal proliferations in stored cocoa beans. The proliferations were however brought under significant control by neem ash treatments. The inclusion of neem ash (particularly at 20 g/kg beans) as a component of integrated management of toxigenic and non-toxigenic mouldiness in stored cocoa beans varieties is therefore essential towards maintaining cocoa bean quality.