Formulation of Aqueous Drinks Using Tigernut and Moringa Seeds: Effect of Adding Chemical Hurdles and Fortificants on Physico-Chemical and Rheological Properties

Abstract

The study was undertaken to determine the physico-chemical and rheological properties of tigernut and moringa seeds based aqueous drinks influenced by chemical hurdles and fortificants. The aqueous drink was produced using a 100:0, 90:10, 80:20, 70:30, 60:40, and 50:50(w/w) tigernut (T) moringa seeds (M). These were subjected to sequential affective and descriptive sensory evaluation and yielded (90:10) ratio as the most preferred plain drink (PTMD). The PTMD was then subjected to a 3×3 experimental design comprising 3 levels of sugar (0, 1, 2 %) and 3 levels of citric acid (0, 0.1, 0.2%) treatments followed by sensory evaluation that yielded (PTMD) containing 2% sugar and 0.2% citric acid as most acceptable (TMSC) which was subsequently subjected to triple fortification using 0.15mg KI, 2.0 mg FeSO4 and 1.6mg retinol palmitate/100g each to yield (TMSCFD). The 3 working products (PTMD, TMSC and TMSCFD) were then subjected to physico-chemical analysis and rheological test. Data obtained from rheological tests were fitted into power law model to obtain the flow behaviour indices. The use of hurdles and fortificants significantly (p<0.05) increased the proximate composition with the protein ranging from 25.8-26.4, carbohydrates 19.4-27.3, Ash 0.77-4.4, Fibre 20.6-32.3 and moisture 66.1-69.0%. Fortification significantly (p<0.05) increased the Fats from 7.01-10.05, Iron, Iodine and Pro-Vitamin A values 2.90-4.80, 0.00-0.15 and 0.94- 2.48, the specific gravity of the aqueous drink ranged from 1.64 -1.89, TTA ranged from 0.62-0.66 and pH values ranged from 6.3- 6.8 respectively. The 3 products exhibited pseudo-plastic flow patterns with flow bahaviour indices (n) and consistency indices (m) ranging from 0.66-0.68 (PTMD), 0.65-0.79 (TMSCD) and 0.39-0.48 (n) (TMSCFD), 0.31-0.49 (PTMD), 0.13-0.419 (TMSCD) and 2.19-2.45 Ns/m (TMSCFD) respectively.  This results implies that chemical hurdles and fortificants improved the physico-chemical properties of tigernut and moringa seeds aqueous drinks by extending its shelf life and providing adequate nutrients for addressing protein energy malnutrition.