Mycoflora and nutrient analysis of sundried cassava chips (Manihot esculenta) during storage

Objectives: The mycoflora and nutritional status of sundried cassava chips (Manihot esculenta) during twenty weeks of storage and the effects of their presence on the nutrient composition were investigated.Methodology and Results: Samples of healthy fresh cassava were obtained, processed and stored. The fungi species associated with both fresh and stored chips were isolated at different time intervals using direct plating, washing and dilution methods while proximate and mineral composition of the fresh and stored cassava chips were analysed using standard procedures. Six fungi were isolated namely: Absidia sp., Aspergillus flavus, Aspergillus glaucus, Fusarium moniliforme, Neurospora sp., and Rhizopus nigricans. The fungi were found to increase as the storage time increases though constancy exists. The results of proximate composition in g/100g showed that ash decreased from 2.44 to 1.68, fat 0.44 – 0.23, fibre 0.48 – 0.16 while the following parameters were found to increase viz moisture 15.87 – 16.54, crude protein 3.60 – 3.63 and carbohydrate 77.18 – 77.77. The results of mineral analysis in mg/100g revealed that all minerals decreased with storage period viz sodium (Na) 24.22 – 14.14, potassium (K) 48.08 – 23.19, calcium (Ca) 9.49 – 4.36, magnesium (Mg) 6.06 – 3.03, zinc (Zn) 4.79 – 2.22, iron (Fe) 0.36 – 0.20 and phosphorus (P) 33.56 – 25.59. Copper (Cu), manganese (Mn) and lead (Pb) were not detected in the samples.Conclusion and application of findings: This study demonstrates the importance of proper processing and storage of cassava chips. The study also established that field sun-drying might result to contamination by air borne fungal spores. The nutritional composition of cassava chips were depleted by the associated fungi during storage. Therefore, drying should be done under controlled environment such as the use of solar driers, low cost ovens and store in airtight moisture free environment that will not favour the growth of spoilage and nutrient depleting fungi.Keywords: Minerals, proximate analysis, crude protein, cassava chips, spoilag