Food-to-Food Fortification of a Traditional Pearl Millet Gruel with a Natural Source of β-Carotene (Sweet Potato) Improves the Bioaccessibility of Iron and Zinc

Abstract

Iron and zinc deficiencies are still a major public health concern in the Far North Region of Cameroon where staple foods are mainly mineral rich cereals which equally contain inhibitors of their bioaccessibility. The effect of food-to-food fortification of a traditional pearl millet gruel with a natural source of β-carotene on the bioaccessibility of iron and zinc was assessed. A sensory evaluation of gruels fortified at 20, 30, and 40% with mashed sweet potato was carried out. The samples were analysed for carotenoids, phytates, polyphenols, iron, and zinc contents. Bioaccessible iron and zinc were evaluated using in vitro digestion method. The gruel fortified at 20% with mashed sweet potato had better scores ( $P$  < 0.05) of taste (3.93), colour (3.36), and overall acceptability (3.80) compared to the control. Carotenoid, polyphenol, and phytate contents were higher in fortified gruels ( $P$  < 0.05) compared to the control, while iron and zinc contents were lower. A significant increase ( $P$  < 0.05) in bioaccessibility of 8.08% and 26.96% for iron and 53.79% and 62.92% for zinc was observed at 20 and 30% incorporation level, respectively. However, at 40% incorporation level, the increase in bioaccessible iron was less important and bioaccessible zinc decreased. Mashed sweet potato can be used as a fortificant to improve the bioaccessibility of iron and zinc contents of local pearl millet gruel, if added moderately.