Sustainable Production of Peanut Protein Isolate: Optimization, Functional Characterization, and Comparison With Soy Protein

ABSTRACT The agri‐food industry seeks sustainable and plant‐based protein sources that valorize industrial by‐products to meet the nutritional demands of the growing population and circular economy goals. In this context, a hexane‐free peanut protein isolate (PPI) was developed from pressed peanut oil cake—a major by‐product of the Argentine oil industry—using an optimized alkaline extraction process designed to maximize protein yield. The process achieved a protein yield of 70.19% and a purity of 90.1% (dry basis) under optimal conditions (75°C, pH 11, water/solid ratio 20:1, 60 min). To evaluate its potential as a bio‐techno‐functional ingredient, the PPI was compared with a commercial soy protein isolate (SPI) in terms of antioxidant activity, composition, techno‐functional properties, protein profile, and thermal behavior. PPI exhibited higher antioxidant activity, solubility (93.9% vs. 42.9%), and emulsifying activity index, as well as lower denaturation compared with SPI. Cytotoxicity assays confirmed its in vitro safety at all tested concentrations. These results position PPI as a clean‐label, sustainable, and functional alternative to SPI, suitable for various food applications—especially those requiring protein‐enriched formulations with high solubility, such as high‐protein beverages. Moreover, the hexane‐free process promotes the upcycling of peanut by‐products, ultimately positioning PPI as a strategic protein source originating from South America that contributes to nutrition, wellness, and sustainability in line with global regulatory and market trends for novel plant proteins.