Prebiotic effects of cassava fibre as an ingredient in cracker-like products.

Cassava fibre, a waste product formed in starch production, was incorporated into wheat to give composite flours at ratios of 80/20, 70/30, 60/40 and 50/50, respectively. A cracker-like biscuit was produced from the preferred ratios (60/40 and 50/50). The effects of these on diets as a prebiotic were evaluated in a rat assay. Determinations of the proximate composition and haematological parameters were made as well as microbiological analysis. The protein content of the cracker-like product based on the 50/50 and 60/40 (fibre/wheat flour) ratios were 15.0% and 10.0%, respectively. Crude fibre ranged from 14.1-17.1% while ash ranged from 3.0 and 5.0%. Low cholesterol levels of 28.75 mg dL(-1) and 18.75 mg dL(-1) were recorded for the 50/50 and 60/40 composite ratios, respectively. The result of liver function test showed that the rats that were fed the fibre-based cracker product had an average value of 44.00 IU L(-1) of aspartate amino transferase (AST), which is lower than the 67.75 IU L(-1) recorded for the control. There was a significant increase in the packed cell volume (PCV) of the rats fed a fibre-based diet, relative to those fed "Ogi" (fermented maize). Haemoglobin was significantly higher in the control sample than all others, while no significant difference was observed in the white blood cell (WBC) count, with average of 11.75 mm(3). Data obtained from the faecal analysis showed that the rats fed with the composite ratios and other diets had an increased Lactobacillus count. However, by increasing the number of days that the rats were fed the fibre-based diet, the E. coli count in the rat faeces reduced significantly. The data obtained shows that cassava fibre-based crackers have good nutraceutic effects, with reduction in the E. coli count found in the rat faeces and healthy performances in terms of weight gain.