Impact of processing technique on the apparent bioavailability of cooking banana (matooke) starch

Abstract

The aim of the study was to compare the apparent bioavailability of starch in raw, cooked and extruded
matooke flours using weanling mice. Two control and three test groups consisting of seven mice each (initial
body weight of 21.32 ± 1.05 g) were fed diets incorporating soluble unavailable starch (Control I), soluble starch
(Control II) and raw, cooked and extruded matooke flours as carbohydrate bases, for three weeks. The growth
rate, food intake, adipose tissue size and 12 h fasting glucose levels were measured. The mean values of the
growth parameters were separated by ANOVA using GENSTAT statistical package. There was a significant
difference (P<0.001) in food intake between the control and test groups. The mice fed on solubilised matooke
starches (cooked and extruded) exhibited significantly higher (P<0.001) growth rates than the ones fed on raw
starch, showing a higher apparent bioavailability of the former flours. The mice fed on Control I appeared
malnourished despite an excessively high food intake. The raw matooke group displayed less pronounced
symptoms of malnourishment despite recording the highest weight loss. The fat pad sizes were in agreement
with the growth rate data. The glucose levels, though on the lower side particularly in the Control I and raw
matooke flour groups, were within the normal range. The results demonstrated that solubilised matooke
starches adequately met the energy requirement of a growing animal. Nonetheless extrusion cooking appeared
to confer a marginal advantage over the cooked flour, due to extruded flour’s lower peak viscosity. This
advantage would be enhanced in humans if the rations are taken as porridges.