Enhancement of Bioactive Constituents and Antioxidant Properties of Orange-Fleshed Sweet Potato Flour Supplemented with Detarium microcarpum

Abstract

Orange-fleshed sweet potato (Ipomoea batatas) is recognized as a functional food crop with significant nutraceutical potential due to its rich bioactive compound profile. This study investigated the enhancement of bioactive constituents and antioxidant properties of orange-fleshed sweet potato flour through supplementation with Detarium microcarpum at 5% and 10% concentrations. The composite flours were analyzed for phytochemical composition (total phenolics, saponins, tannins, and flavonoids), antioxidant activities (DPPH, ABTS, and reducing power), and enzyme inhibitory activities (α-glucosidase, α-amylase, and angiotensin-converting enzyme). Results demonstrated that supplementation with D. microcarpum significantly enhanced the bioactive compound profile, with the 90% orange potato: 10% D. microcarpum blend showing the highest tannin content (16.78±0.23 mg tannic acid equivalent/g), while the 95% orange potato: 5% D. microcarpum blend exhibited the highest flavonoid content (0.43±0.03 mg quercetin equivalent/g). The 95% orange potato: 5% D. microcarpum composite demonstrated optimal antioxidant enhancement with the highest reducing power (4.55±0.01 mg gallic acid equivalent/g) and superior DPPH scavenging activity (SC₅₀ = 1.89±0.01 mg/mL). However, supplemented samples showed reduced enzyme inhibitory capacity compared to pure components. The novelty of this study lies in demonstrating the synergistic enhancement of bioactive compounds through strategic blending of underutilized African indigenous plants with orange-fleshed sweet potato. These findings provide scientific evidence for developing nutrient-dense functional foods that could address malnutrition and support health promotion in regions where both crops are readily available, particularly for managing oxidative stress-related conditions.