This study investigated the chemical composition of biscuits formulated from acha (Digitariaexilis), malted pigeon pea (Cajanus cajan), and peanut paste as a functional substitute for conventional baking fat. Eight formulations (Samples A–H) were produced with progressive substitution of peanut paste (0–30%) and analyzed for proximate composition, vitamins, phytochemicals, minerals, antinutrients, and in vitro digestibility.Proximate analysis revealed significant (p ≤ 0.05) improvements in protein (12.13–20.02%), fat (6.36–8.72%), fiber (0.64–1.10%), and ash (6.68–9.79%) with corresponding reductions in carbohydrate (69.25–53.89%). Vitamin assays showed enrichment of vitamin E (0.39–4.94 µg/100 g) and riboflavin (0.25–0.70 mg/100 g), though vitamin B12 was undetected. Phytochemical content increased markedly, with carotenoids, total phenolics, and flavonoids reaching 80.35 µg/100 g, 60.37 mg/100 g, and 37.69 mg/100 g, respectively, in the most enriched formulation. Mineral composition also improved significantly, with magnesium, potassium, calcium, sodium, and zinc levels rising to 178.43, 665.24, 364.91, 94.22, and 10.16 mg/100 g, respectively. Antinutrient concentrations (cyanide, phytates, tannins) increased but remained below established safety thresholds. Importantly, in vitro protein and starch digestibility were significantly enhanced, peaking at 83.72% and 82.97% in biscuits containing 30% peanut paste.The findings demonstrate that acha–pigeon pea–peanut paste composite biscuits represent a nutritionally superior alternative to conventional formulations. By combining local, underutilized crops, these biscuits provide enhanced protein quality, micronutrient density, and bioactive compounds, offering a functional food with strong potential for addressing protein-energy malnutrition and micronutrient deficiencies in resource-limited settings.
