Nutritional and Some Phytochemical Profiling of Pigeon Pea (Cajanus Cajan) Seed Meal: Exploring Its Potential as A Sustainable Protein Source

Abstract

Nutritional and phytochemical profiling of underutilized legumes is critical for diversifying sustainable protein sources in tropical food systems. This study evaluated the effects of processing on the proximate composition and phytochemical profile of pigeon pea (Cajanus cajan) seed meal and its incorporation into composite diets. Raw seed meal contained 87.00% dry matter, 3.20% ash, 2.00% crude fat, 6.25% crude Fiber, 10.85% crude protein and 74.35% carbohydrate. Processing of the seed meal modulated these constituents: moisture decreased from 3.35% (raw) to 2.52% (boiled) and 2.05% (toasted); crude protein ranged from 27.43–31.55%, with toasting giving the highest value (31.55%); crude Fiber varied between 4.13–4.46%, and ash between 3.25–3.61%. Incorporation of processed pigeon pea into diets (4–12%) maintained crude protein at 16.74–17.88%, with toasted 12% inclusion achieving 17.88% protein, 4.32% Fiber and 2.89% ash, alongside modest moisture (2.47–4.54%) and carbohydrates (57.15–62.69%). Thermal processing drastically lowered anti-nutritional factors: oxalate (2.43 to 0.90–1.08 mg/g), phytic acid (10.71 to 2.24–1.06 mg/g), saponins (24.72 to 0.91–1.63 mg/g), tannins (4.17 to 0.92–1.17%), and trypsin inhibitor (29.40 to 2.01–1.61%). Collectively, these results demonstrate that especially toasted C. cajan seed meal combines high crude protein (up to 31.55%), appreciable Fibre (up to 10.00%), improved dry matter (88.87%) and markedly reduced anti-nutrients, supporting its utilization as a sustainable plant-based protein ingredient in value-added foods and feeds. Conclusively, thermal processing transforms raw pigeon pea, naturally limited by anti-nutrient content, into a more nutrient-dense, protein-rich, and lowered-moisture ingredient. Further investigations on amino acid profile, digestibility, bioavailability, and functional properties to maximize its utilization is thus recommended.