C-Phycocyanin, one of the most important functional components in Spirulina, is widely used in foods, beverages, dietary supplements, and cosmetic formulations due to its natural blue color, outstanding antioxidant activity, and unique protein structure. As consumer demand for natural pigments and functional botanical ingredients continues to grow, how to extract high-purity C-phycocyanin has become a critical topic in the industry.

This study compares four commonly used extraction techniques-oscillation extraction, high-speed homogenization, ultrasonic extraction, and repeated freeze–thaw extraction-and systematically evaluates their effects on the purity, structural characteristics, and functional properties of the protein.

1. Optimal Extraction Technique: The Repeated Freeze–Thaw Method Yields the Highest Purity C-Phycocyanin

The study showed that all four extraction methods successfully obtained C-phycocyanin from Spirulina, but their efficiencies differed significantly:

Repeated freeze–thaw extraction (RFE): Achieved the highest purity (2.68), with the most complete cell disruption. It is one of the most effective methods for extracting high-purity C-phycocyanin to date.

High-speed homogenization (HHE): Produced good results and is suitable for large-scale industrial applications.

Ultrasonic extraction (UE): Demonstrated moderate efficiency.

Oscillation extraction (OE): The most basic method, yielding the lowest purity.

Purity Comparison of Extraction Methods

These findings are particularly important for food manufacturers, ingredient suppliers, and industries exploring Spirulina as a functional food component.

2. Structural Stability: Higher α-Helix Content Leads to Better Functional Performance

FTIR analysis revealed that C-phycocyanin extracted via the repeated freeze–thaw method exhibited the highest α-helix content, indicating superior molecular stability-an essential factor influencing its performance in food and cosmetic applications.

Additionally, SDS-PAGE results showed that all samples retained complete α and β subunits, confirming the typical molecular structure of C-phycocyanin derived from Spirulina.

These structural features also explain its effectiveness in cosmetic applications, such as antioxidant protection, blue-light defense, and cellular protection.

3. Superior Functional Properties: Best Solubility, Emulsification, and Foaming Performance

3.1 Solubility

Across the pH 4–10 range, all samples demonstrated good solubility, but C-phycocyanin extracted via the repeated freeze–thaw method showed the highest solubility.

This is highly beneficial for industries such as:

Plant-based beverages

Instant powdered drinks

Natural blue-colored beverage formulations

Applications requiring natural alternatives to FD&C Blue No.1

3.2 Emulsifying & Foaming Properties

C-phycocyanin possesses excellent emulsifying and foaming capabilities, closely related to its solubility and structural integrity. The repeated freeze–thaw method produced samples with the strongest emulsifying and foaming performance, suitable for:

Functional beverages

Bakery products

Dairy and plant-based dairy alternatives

Oil-containing food systems

These attributes align with industry interests in phycocyanin emulsifying properties and phycocyanin solubility.

3.3 Water- and Oil-Holding Capacity

Samples extracted via the repeated freeze–thaw method exhibited the highest water- and oil-holding capacities, important for:

Texture improvement

Moisture retention

Product stability

3.4 Gelation Ability

A lower minimum gelation concentration indicates stronger gelation capacity.
This makes C-phycocyanin applicable in:

Plant-based foods

Gummy and gel confections

Functional snacks

4. Antioxidant Performance: Significant Radical-Scavenging Activity

The study demonstrated that increasing C-phycocyanin concentration (from 25 μg/mL to 250 μg/mL) significantly enhanced its DPPH and ABTS radical-scavenging activities.

Key results:

Samples extracted by the repeated freeze–thaw method showed the highest scavenging rate at 250 μg/mL

They also exhibited the lowest IC₅₀, indicating the strongest antioxidant capacity

These findings confirm that C-phycocyanin provides:

Free radical scavenging

Oxidative stress reduction

Cellular protection

These mechanisms highlight why C-phycocyanin is one of the most valuable bioactive compounds in Spirulina, widely used in nutraceutical and cosmetic formulations.

5. Application Trends: Growing Use in Food, Beverage, Nutrition, and Cosmetics

Thanks to its coloring properties and antioxidant potential, C-phycocyanin is becoming increasingly valuable in the following sectors:

Food & Beverage

Natural blue beverages

Confectionery and gel-based products

Protein drinks

Healthy snacks

Nutraceuticals

Antioxidant supplements

Anti-glycation and anti-inflammatory formulas

Immune-support products

Cosmetics

Antioxidant skincare

Blue-light protection

Soothing and repair formulas

6. Summary

Considering extraction efficiency, structural stability, functional performance, and antioxidant activity, the repeated freeze–thaw method is currently the optimal technique for obtaining high-purity C-phycocyanin. It yields a stable, high-functionality protein suitable for applications in food, nutrition, and cosmetic industries.

As global demand increases for natural blue pigments, functional Spirulina-derived ingredients, and Spirulina extract antioxidant activity, C-phycocyanin is expected to become one of the most important natural ingredients in the future food and nutrition sectors.