Unlocking the protein potential of underutilized ethiopian Lupinus spp.: Optimization of extraction conditions and chemical characterization

The growing demand for sustainable proteins has spotlighted Lupinus spp., an underutilized legume valued for its high protein content and nutritional potential. The study aimed to optimize protein isolate extraction pH (EpH) and isoelectric precipitation pH (IEPpH) across four Ethiopian Lupinus genotypes using Central Composite Design (CCD). Genotype-specific differences were observed in moisture (6.01–7.97 g/100 g), crude protein (39.9–47.8 g/100 g), ether extract (6.26–13.3 g/100 g), essential amino acid index (62.61–70.7%), and total alkaloid content (1.76–11.1%). The Vitabor cultivar exhibited the highest protein purity (92.1%) and yield (29.0%) at EpH 8.5 and IEPpH 4.5, while Gibto showed the highest recovery (57.5%). All genotypes achieved the lowest alkaloid levels at EpH 10 and IEPpH 5, emphasizing the detoxification role of extraction pH. The optimized conditions were genotype-specific, indicating that customized parameters improve isolate yield, purity, and safety. Vitabor shows strong promise as a sustainable protein source for climate-smart food systems in protein-insecure regions. Gibto and Probor genotypes offer potential for therapeutic and food applications. However, further research on techno-functional and molecular properties is needed to guide their integration into functional, plant-based food products. • Central composite design optimized protein extraction of Ethiopian lupine genotypes • Extraction and isoelectric pH significantly influenced isolate yield and purity • Vitabor showed the highest EAA content, protein yield, purity, and lowest alkaloid • Gibto achieved the highest protein recovery among all tested genotypes • Genotype-specific responses show the potential for targeted functional applications