Abstract
Yam is a widely consumed staple food but has a high carbohydrate content and limited functional attributes. This study evaluated the nutritional, antioxidant, and in vitro antidiabetic properties of doughmeals produced from yam and tigernut flour blends at ratios of 95:5, 90:10, 85:15, 80:20, and 100% yam (control). Results showed that tigernut inclusion significantly improved the nutritional profile, with protein increasing from 8.09% to 11.81% and crude fiber rising from 0.24% to 1.14%. Ash and fat contents also increased notably, reflecting the mineral-dense and lipid-rich nature of tigernut. Phytochemical analysis revealed a substantial boost in total phenolic content, peaking at 14.07 mg GAE/g in the 20% blend compared with 6.56 mg GAE/g in the control. These compositional changes improved the functional and antioxidant potential of the doughmeals. Antioxidant capacity improved significantly across all assays, with hydroxyl radical scavenging nearly doubling (37.73% to 74.15%) and ABTS activity reaching 88.69%. Critically, the blends demonstrated significant in vitro inhibitory activity against key carbohydrate-digesting enzymes. Alpha-amylase inhibition rose from 43.74% to 80.61%, while alpha-glucosidase inhibition reached 72.56% in the fortified samples. Sensory evaluation confirmed that these improvements did not compromise consumer appeal, as overall acceptability remained statistically comparable to the traditional control. The findings indicate that tigernut incorporation, up to 20%, enhanced the nutritional composition, antioxidant capacity, and in vitro carbohydrate-digesting enzyme inhibitory potential of the doughmeals.