Sustainable valorization of almond and peanut plant-based milk cakes: The use of terpenoid mixtures as ready-to-use solvents to enhance supercritical CO2 extraction

Abstract

The solid cake from plant-based milk production, rich in lipids and proteins, can be repurposed to recover valuable fractions suitable for food, cosmetics, and pharmaceutical applications. This innovative study explored terpenoid-based solvents as modifiers of supercritical CO₂ extractions to obtain ready-to-use extracts rich in fatty acids, bioactive compounds, and a protein concentrate derived from almond and peanut biorefinery. The natural mixtures of 1:1 menthol:1,8-cineole (ME:EU) and 1:2 camphor:1,8-cineole (CA:EU) used at concentrations of 7.5 and 15 % increased bioactive compounds and lipids yield, outperforming other extraction methods. The phase transition of the system CO₂ and ME:EU shows a homogeneous liquid phase, contributing to solvation power and extraction yield. The ME:EU and CA:EU extracts presented low cytotoxicity to human kidney HK-2 cells, showing potential for ready-to-use purposes. The extraction method had little effect on the functional properties of the proteins. Moreover, the continued supercritical CO₂ extraction allowed solvent remotion and reuse.

Keywords: Camphor:eucalyptol; Cytotoxicity; Fatty acids; Menthol: eucalyptol; Phase equilibrium; Plant proteins.