Recovery of quinoa protein via ultrasound-assisted extraction and nanoparticle-enhanced foam fractionation: stabilizer preparation, mechanistic insights and process optimization

Abstract

This study presents an innovative, sustainable strategy for high-efficiency recovery of quinoa protein through synergistic integration of ultrasonic extraction and foam fractionation stabilized by sodium caprate-functionalized cellulose nanoparticles (SC-CNPs). The surface engineering of CNPs via SC modification was systematically characterized using SEM-EDX, FTIR, XPS, and zeta potential analysis, revealing successful grafting of aliphatic chains that transformed CNPs into amphiphilic stabilizers with optimal interfacial activity (contact angle: 79.7°). This modification extended foam half-life by 26.7-fold compared to unmodified CNPs, enabling robust foam stability for protein recovery. Through Box-Behnken design optimization (150 mg/L SC-CNPs, pH 4.8, 530 mL/min gas flow), the process achieved exceptional recovery efficiency (93.1 %) and enrichment ratio (15.9). Compositional profiling confirmed the preservation of native quinoa protein structures, with better functional properties. Nutritionally, the protein met FAO/WHO essential amino acid requirements, validating its suitability for food fortification, cosmetic emulsions, and pharmaceutical encapsulation. By bridging colloidal science, green chemistry, and circular bioeconomy principles, this work establishes nanoparticle-enhanced foam fractionation as a paradigm-shifting technology for sustainable valorization of plant proteins, offering transformative solutions for global food security and eco-friendly biorefining.