Optimization of composite flour for the production of thermo extrudates made from African breadfruit seeds, orange-fleshed sweet potato and tigernut

Production of thermo-extrudates from composite flours utilizing local crops is imperative to improving the nutritional benefits of the products and over reduction in overdependence on wheat. The study investigated the quality characteristics of thermo-extrudates made from composite flour of African breadfruit seeds (ABF), orange-fleshed sweet potato (OFSP) and inclusion of tigernut (TGN). 14 experimental runs were generated with the use of Simplex centroid mixture design. Standard laboratory methods were applied to determine the proximate composition, texture, mineral, colour profile and beta-carotene retention of thermo-extrudates. Data obtained were analyzed using Design expert 6.0.8 (Stat-Ease, Inc., Mineaplolis) software was used to formulate the ratios of the flours in the mixture of the three components where X1, X2, and X3 represented African breadfruit, Orange-fleshed sweet potato, and Tigernut flour, respectively and the thermo-extrudates were optimized by choosing the desired criteria. The BD, WAC, WSI and ER of the extrudates ranged from 0.63 to 0.73 g/mL; 1.82 to 3.81 g/g; 10.10 to 17.59% and 1.69 to 1.95%, respectively. The beta-carotene retention of the extrudates increased as inclusion of OFSP in the blends increased. The optimized ABF-OFSP-TGN extrudates were obtained from ABF (51.0%), OFSP (41.0%) and TGN (8.0%) at desirability level 0.75 and rated high in terms overall acceptability. Thermo-extrudate rich in nutrients and beta-carotene was produced from ABFS-OFSP-TGN composite flour by applying the optimized process conditions.