Supercritical Carbon Dioxide Applications in Protein Processing

Supercritical carbon dioxide (sCO2) has emerged as a versatile tool in protein processing, exploiting its unique physicochemical properties above 31 °C and 7.38 MPa. In this state, CO2 combines liquid-like density with gas-like diffusivity, enabling rapid mass transfer and gentle treatment of delicate biomolecules. The ability to tune pressure and temperature permits precise control of solvent power, pH and density, making sCO2 a valuable agent for protein fractionation, precipitation, gelation and structural modification. Unlike traditional acid or thermal treatments, sCO2 offers non-thermal, environmentally benign processing that preserves protein functionality, reduces solvent residues and minimises degradation. Protein fractionation under sCO2 relies on gradual acidification from carbonic acid formation, selectively precipitating target fractions such as α-lactalbumin or β-lactoglobulin from whey isolates. Gelation applications employ dense-phase CO2 to induce conformational changes and cross-linking in surimi and other muscle proteins, yielding fine, uniform networks with enhanced strength and water-holding capacity. Emerging studies extend sCO2 treatments to plant-based proteins, improving techno-functional properties such as emulsification, foaming and solubility. Collectively, these advances underscore the global significance of sCO2 in producing high-purity protein isolates, novel gel structures and tailored proteins for food, pharmaceutical and biomaterial applications.

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Supercritical Carbon Dioxide Applications in Protein Processing publication trend

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Technical terms

Supercritical carbon dioxide (sCO2): carbon dioxide above its critical temperature and pressure, exhibiting combined gas and liquid properties for solvent-free processing.

Dense phase carbon dioxide: CO2 at pressures near or above its critical point used to induce non-thermal protein modifications through acidification and conformational change.

Gelation: assembly of protein molecules into a three-dimensional network entrapping water, resulting in a viscoelastic gel structure.

Fractionation: selective separation of protein components based on differences in solubility or precipitation under controlled pH or solvent conditions.

Techno-functional properties: characteristics such as emulsification, foaming, water-holding and gel strength that determine protein performance in food or material applications.

References

1. Correlation between Water Characteristics and Gel Strength in the Gel Formation of Golden Pompano Surimi Induced by Dense Phase Carbon Dioxide. Foods (2023).
2. Fractionation of Whey Protein Isolate with Supercritical Carbon Dioxide—Process Modeling and Cost Estimation. International Journal of Molecular Sciences (2011).
3. Supercritical CO2 Treatment to Modify Techno-Functional Properties of Proteins Extracted from Tomato Seeds. Foods (2024).