Microbiological and physicochemical evaluation of starch produced from cassava and maize

Abstract

The qualitative assessment of cassava and maize starch revealed that the mean counts of viable bacteria were 4.8 x 103cfu/g and 3.7 x 103cfu/g for cassava starch (CS) and maize starch (MS) respectively. The coliform counts were 2.9 x 103cfu/g and 3.0 x 103cfu/g for CS and MS respectively while the fungi counts were 3.53 x 102cfu/g and 4.2 x 102cfu/g for CS and MS respectively. The mean counts for commercial starch was recorded as 1.5 x 103cfu/g, 3.33 x 102cfu/g and 1.9 x 102cfu/g for total viable bacteria, coliform and fungi respectively. The microbial isolates were identified as Bacillus alvei, Escherichia coli, Serratia marcescens, Staphylococcus aureus and Saccharomyces cerevisiae (yeasts). The starch from both products were odourless, tasteless, insoluble in water and in alcohol. There was a slight dissimilarity in color with CS and commercial starch being white and MS appearing slightly yellow. The pH was 7.48 for CS, 6.50 for MS and 5-7 for commercial starch while the ash content was 0.50% for CS, 0.36% for MS and 0.1-0.6 for commercial starch. The moisture content for CS, MS and commercial starch was 6.5%, 8.0% and 10.0-12.0% respec- tively while the fibre content was 0.023% for CS, 0.048% for MS and 0.2 for commercial starch. The starch also had varying amounts of fat and starch content. The results suggest that starch produced locally from cassava and maize are contaminated with microorganisms and have some physico- chemical qualities that do not meet acceptable standard for industrial starch.