African maize porridge: a food with slow in vitro starch digestibility

The incidence of diabetes is very low in rural, traditionally living, South African Black people, but higher in the urbanised Black population. One factor, that could have contributed to the increased prevalence of diabetes, is the change in diet from maize porridge to bread. An in vitro method was used to determine the starch digestibility of African maize porridge compared to other cereal foods. Maize porridge had a much lower in vitro starch digestibility than white bread (P<0.001). There was a positive correlation (P=0.05) between rate of starch digestibility of maize porridge and endosperm hardness. Decreasing the particle size of the maize meal by conversion to maize flour did not increase starch digestibility. Both decreasing and increasing the cooking time decreased the starch digestibility. The predicted glycaemic index for maize porridge ranged from 39 to 50 (glucose standard), which suggests that maize porridge may be useful in the dietary management of diabetes.