Folates in various African foods: Contents, food processing and matrix effects

Poor folate status is implicated in a wide variety of health disorders including megaloblastic anaemia, neural tube defects, and cardiovascular diseases. Human diet remains the main provider par excellence. Despite several public-health options to overcome this micronutrient deficiency, dietary folate intakes of women of childbearing age and children are still below recommendations in many African countries. Therefore, this review aims at presenting the current knowledge on folate contents in various African foods, and on folate losses during food processing. Seventy one food sources were evaluated in this study. These various food sources included thirty six vegetables, six cereals, height cereal products, six processed leafy vegetables, six pulses, three fruits, three legumes and three roots. All of them were originated from six African countries including Burkina Faso, Côte d'Ivoire, Egypt, Ethiopia, Nigeria, and South Africa. Folate content ranged between 11 and 73.4 μg/100 g in cereals, 1.8 and 39 μg/100 g in cereal-based processed foods, 8.48 and 48.6 μg/100 g in cooked leafy vegetables, 11.6 and 633 μg/100 g in vegetables, 10 and 22 μg/100 g in pulses, 52 and 148 μg/100 g in legumes, 8 and 106 μg/100 g in fruits. The structure of the food matrix has been shown to influence folate digestibility in foods. High bioaccessible folate, assessed by in vitro digestion, was observed among food products with dense porosity structures while low bioaccessible folate was recorded among food products with open porous structures such as porridges and some gelatinized doughs. Numerous food processing steps have also been shown to influence negatively folate contents in foods.