Fonio (Digitaria exilis) landraces in Mali: Nutrient and phytate content, genetic diversity and effect of processing

The study aimed to assess (i) the genetic diversity of fonio (Digitaria exilis) landraces in Mali, (ii) the nutrient and phytate content in fonio products and (iii) the effect of processing on nutrient content of fonio products. Twelve fonio landraces were collected from farmers in central and southern regions of Mali (10 kg/farmer/landrace in paddy form), cleaned and processed in laboratory into paddy, mid wet, cooked and parboiled fonio. Proximate and nutrient composition were determined using the standard AOAC methods. Three genetic groups were identified and between-individual race variation was observed in one group using the Amplified Fragment Length Polymorphisms (AFLPs) method. Mean iron, zinc and phytate concentrations in paddy were 34.6 mg/100 g, 3.2 mg/100 g and 513.7 mg/100 g dry weight. Processing reduced significantly iron, zinc and phytate content to 1.3 mg/100 g, 2.2 mg/100 g and 129.2 mg/100 g dry weight. [Phytate]/[iron] molar ratio in processed products was above the critical value of 1, suggesting poor iron absorption. Parboiling did not reduce iron and zinc losses due to processing.