Leafy vegetables fortification enhanced the nutritional profile and reduced the glycemic index of yellow cassava pasta

Abstract

Food-to-food fortification of yellow cassava flour with leafy vegetable powders (Amaranthus and Telfairia occidentalis) was employed in this study to develop cassava-vegetable spaghetti-like pasta products (YP, YPA5, YPA10, YPU5, YPU10, YPA5O). The nutritional profile, micronutrient retention, bioaccessibility, starch digestibility and in vitro glycemic index were assessed. The incorporation of leafy vegetable powder enhanced the nutritional quality of the yellow cassava pasta (YCP) products. The fortification increased (up to 3-fold) the protein in fortified YCP, increased the fibre (11%), doubled the ash and increased the beta-carotene (about 7-fold), iron (72%) and zinc contents by 10%. The phenolic content of fluted pumpkin leaf-fortified pasta with 10% leaf powder inclusion (YPU10) was 1100 μg GAE g⁻¹, almost four times higher than that of the unfortified YCP. Leaf powders in the cassava pasta also favoured the retention of micronutrients during cooking and slowed down the starch digestibility. The retention during cooking was up to 91% in YPU10 for beta-carotene with no loss in iron, while the bioaccessibility of beta-carotene was impeded, the zinc retention was high and became significantly more bioaccessible with leaf addition and cooking. The estimated glycemic index of YCP was reduced by 19% and 15% in YPU10 and YPA10, respectively. The inclusion of the vegetables also reduced the glycemic index of the fortified YCP. Thus, adding leafy vegetable powder up to 10% into YCP is a promising approach to both valorise yellow provitamin A biofortified cassava and enhance the nutritional value.