Effects of Different Drying Methods on the Mycoflora Associated with Cocoyam (Colocasia esculenta (L) Schott) Chips (Achicha) in Storage

Abstract

Cocoyam (Colocasia esculenta (L) Schott) corms were processed into chips (Achicha) by drying to increase storage life and availability. During this drying process, microorganisms often settle on the exposed surface causing deterioration. In this study, the effect of different drying methods on mycoflora associated with cocoyam chips in storage was evaluated. The corms were washed under flowing tap water, parboiled for 10 minutes, peeled, slice and divided into three equal portions for drying. Three drying methods were used (A = Ambient, O = Oven and S = Sun drying). Dried chips were stored in airtight containers at room temperature (30 ± 2°C) for 3-months period. Observed mycoflora were isolated on agar plates and identified. A total of 961 colonies comprising of 15 species of fungi were recorded including Aspergillus flavus, A. fumigates, A. niger, Botryodiplodia theobromae, Curvalaria lunata, Fusarium solani, Mucor mucedo and Rhizopus stolonifer among others. A. niger occurred most, followed by M. mucedo, F. solani and B. theobromae throughout the period of storage irrespective of drying method employed. Mycoflora occurred in the order of S>A>O while number of fungal colonies increased as the storage period increased with August>July>June. Thus, oven drying cocoyam chips is recommended as this reduced exposure to fungal colonization compared to sun and ambient drying. Since various traditionally processed food including cocoyam chips are consumed in Nigeria, drying in more confined environment with enhanced facilities are needed to improve quality of product, good health and food security for the local populace.