Improvement of Iron and β-Carotene Bioaccessibility in Complementary Foods: Biofortification of Local Crops With Organic Residual Products and Microorganisms

Micronutrient deficiencies remain a great public health challenge worldwide with iron, zinc, and vitamin A being the most problematic. It has been shown that biofortification through agronomic strategies can increase their micronutrient content, but data on the bioavailability remain limited. In Senegal, consumption of cereals and legumes is high, and orange-fleshed sweet potato (OFSP), rich in β-carotene, has been introduced a decade ago. The objective of the present work was to assess the bioaccessibility of iron, zinc, and β-carotene in local complementary foods prepared with millet, cowpea, and OFSP alone or in combination, produced using different agronomic biofortification strategies. Organic residual products were used alone or in combination with microorganisms to produce the abovementioned crops that were used to prepare the complementary foods. Static in vitro digestion was performed to assess the bioaccessibility of the micronutrients, according to a harmonized protocol. The two organic residual products had different effect, as the cow dung alone was inefficient to increase iron and zinc contents as well as their bioaccessibility in millet porridges. However, the use of poultry litter alone or in combination with microorganisms increased iron bioaccessibility in cooked cowpea (27%–29%) compared to the non-biofortified counterpart (9%). Surprisingly, bioaccessible β-carotene was significantly higher (4.1%) in sample of mashed OFSP biofortified with the combination of the different agronomic strategies than in the others (1.4%–2.5%). Portions (150 g) of porridge prepared from the three biofortified crops would cover up to 100% of the daily vitamin A requirements of children aged 6–23 months. The use of a combination the most promising varieties of crops, together with the agronomic strategies, would be a complementary approach to sustainability limit micronutrient deficiencies in a context of monotonous diets.