ABSTRACT

Microbiological and nutritional status of cassava flour was studied. Flours were produced form tubers of three cultivar of cassava TME 419 UMUCAS 37 and TMS 30572 respectively and using both traditional method and high cassava quality flour (HQCF) techniques. Microbiological assessment covered the total microbial count (bacteria and fungi) in both the fermenting legion and produced flour as well as microbial succession during fermention while nutritional assessment covered the determination of proximate composition, mineral and vitamin contents of the flours and hydrogen cyanide content. Results obtained show that the bacteria load of the fermentation water was at averages of 175.67x106 cfu/ml, 168.33 x106 cfu/ml and 189.67 x 106 cfu/ml in TME 419, UMUCAS 37 and TMS 30572 respectively on the first day but reduced to 114 x 106 cfu/ml, 109 x 106 cfu/ml and 122 x 106 cfu/ml on the second day. The fungi load rather increased from 120. 67 x 102 cfu/ml to 145.33 x 102 cfu/ml in fermenting TME 419, 109.0 x 102 to 147.102 cfu/g in fermenting TMS 30572. The bacteria flora of the fermenting cassava was similar having bacteria species which include Staphylococcus aureus, Proteus, Escherichia coli, Bacillus, Pseudomonas, Lactobacillus. Bacillus, Pseudomonas and Staphylococcus aureus were found on the second day. The fungi flora were yeast, Penicillium and Aspergillus species on the first day while Rhizopus and Fusarium were in addition found on the second day. The physiochemical characteristics of the produced flours show a pH range of 5.53 to 6.30 and temperature of 30oC to 31oC with titratable acidity level of 0.73% to 1.27% being higher in the traditional flour than in the HQCF. Nutritional quality of the cassava flour varied between the traditional flours and the HQCF. Protein content was between 1.37 and 1.44% (tradition) and 1.29 to 1.34% (HQCF) while fat content was 0.55% to 0.61% and 0.47% to 0.55%, fibre was 1.15% to 1.23% (traditional) and 1.13% to 1.18% (HQCF). Ash content was higher in a traditional cassava flour (1.25-1.4%) than in the HQCF (1.22 to 1.25%) similar variation were recorded in the moisture content and carbohydrate content. HCN was higher in the traditional flours (39.83 to 61.47mg/kg) than in the HQCF (22.20 to 36.25mg/kg) mineral were varied in both traditional cassava flour and the HQCF in which calcium was between 112.45 and 121.93mg/100g in the traditional and between 121.2 to 136mg/100g while the others magnesium, potassium, sodium, zinc and iron shows significant variation. Similar variation were recorded for vitamins which were generally higher in the traditional flour than in the HQCF. The variation were attributed to the differences in the techniques of production. The higher values of HCN obtained in the traditional cassava flour was attributed to inefficient detoxification while the low cyanide level in the HQCF was attributed to the combined different of heat and leaching following solubilization.