Defatted avocado cake (AVC) is a substantial byproduct of oil processing that serves as a sustainable source for protein recovery, necessitating eco-friendly extraction to replace energy-intensive and toxic conventional methods. This study investigated a holistic, tandem, green process for the recovery of protein from avocado cake using supercritical fluid CO2 extraction (SFE) pretreatment combined with microwave-assisted deep eutectic solvent (DES-MW) extraction comparing to conventional alkaline extraction (CE) and other alternative methods. Results demonstrated that SFE-DES-MW achieved the highest protein content (47.78%) and a recovery rate of 26.40%, significantly outperforming CE. The total amino acid content more than doubled (98.6 mg/g) compared to the conventional method, with notable increases in essential and aromatic amino acids. Structural analysis revealed that the SFE-DES-MW process effectively dissociated large protein aggregates (110–120 kDa) into smaller subunits and induced a conformational shift from rigid β-sheet structures to flexible α-helices. FTIR and XRD analyses confirmed that the extracted proteins were preserved in a salt-free amorphous state. These structural modifications, combined with a high negative zeta potential ( 45.63 mV), resulted in a four-fold increase in water solubility (74%). Consequently, the SFE-DES-MW extracts exhibited superior functional properties, including outstanding foaming capacity (107.90%), foam stability (85.75%), and enhanced water and oil-holding abilities. Additionally, the protein extract showed significantly higher antioxidant activity. Overall, the SFE-DES-MW integrated process offers an efficient and sustainable strategy for valorizing avocado processing waste into high-value functional food ingredients.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)