Aqueous Enzymatic Extraction of Plant Proteins

Aqueous enzymatic extraction (AEE) utilises water as the solvent and specific enzymes to disrupt plant cell walls and liberate intracellular proteins. By selecting enzymes such as cellulases, pectinases or proteases, this method achieves high protein yields under mild conditions, avoiding organic solvents and high temperatures that can denature proteins or generate hazardous waste. The process typically involves an initial slurry of defatted plant material in water, controlled adjustment of pH and temperature to optimise enzyme activity, incubation to allow cell wall hydrolysis, and separation of liquid and solid phases. The liquid extract is then fractionated into “cream” (oil-rich) and “skim” (protein-rich) streams, which may be further purified. AEE has been applied to oilseed cakes, nut flours and pulses, delivering protein isolates and concentrates with favourable functional properties such as solubility, emulsification and foaming. These extracts are increasingly valued for food formulations, nutraceuticals and sustainable protein supply chains, offering reduced energy consumption and environmental impact compared with conventional solvent-based processes.

Research from Nature Portfolio

Recent studies have examined the biological and functional attributes of proteins recovered via AEE from nut by-products. One investigation compared purely aqueous extraction with enzyme-assisted aqueous extraction of almond cake, revealing that enzyme assistance markedly enhanced antioxidant capacity and selective inhibition of metabolic enzymes. Extracts displayed distinct profiles of phenolics and peptides, with enzyme-assisted skims showing uncompetitive inhibition of α-glucosidase and high lipase inhibition, indicating potential as nutraceutical ingredients for metabolic syndrome management. Digestibility assays demonstrated efficient hydrolysis by digestive proteases across extraction modes, underscoring the suitability of these protein fractions for human nutrition and functional food development.

Aqueous Enzymatic Extraction of Plant Proteins publication trend

The graph below shows the total number of articles in aqueous enzymatic extraction of plant proteins across all publications each year (not limited to Nature Index journals).

Technical terms

Aqueous enzymatic extraction: A process using water and specific enzymes to rupture plant cell walls and release proteins without organic solvents.

Degree of hydrolysis: The proportion of peptide bonds cleaved by enzymes, expressed as a percentage, indicating the extent of protein breakdown.

Solid-to-liquid ratio: The mass of plant material relative to the volume of extraction solvent, which influences enzyme diffusion and yield.

Emulsification: The capacity of proteins to stabilise oil-in-water dispersions by adsorbing at the oil–water interface and reducing interfacial tension.

References

1. Effects of protease-assisted aqueous extraction on almond protein profile, digestibility, and antigenicity. Current Research in Food Science (2023).
2. Biological properties of almond proteins produced by aqueous and enzyme-assisted aqueous extraction processes from almond cake. Scientific Reports (2020).
3. Study on Extraction of Peanut Protein and Oil Bodies by Aqueous Enzymatic Extraction and Characterization of Protein. Journal of Chemistry (2020).
4. Effects of Processing Conditions on the Simultaneous Extraction and Distribution of Oil and Protein from Almond Flour. Processes (2019).