Improved pH stability, heat stability, and functionality of phycocyanin after PEGylation

Area of Science:

• Biochemistry
• Food Science
• Materials Science

Background:

• Phycocyanin (PC), a protein-chromophore from spirulina, has limited techno-functional properties and is unstable to heat and pH.
• Aggregation and color changes hinder its application in food and pharmaceuticals.

Purpose of the Study:

• To improve the techno-functional properties and stability of phycocyanin.
• To enhance its applicability in food and pharmaceutical industries through modification.

Main Methods:

• Phycocyanin was modified using PEGylation with methoxy PEG (mPEG).
• Successful conjugation was confirmed using electrophoresis and Fourier transform infrared spectroscopy.
• Circular dichroism was used to analyze protein folding and stability.

Main Results:

• PEGylated phycocyanin (mPEG-PC) showed enhanced structural stability and high blue color intensity.
• mPEG-PC exhibited improved solubility, techno-functionality (emulsifying, foaming, gelling), and antioxidant activity.
• The modified PC demonstrated excellent color stability across a wide pH range (2-9) and upon heating.

Conclusions:

• PEGylation effectively stabilizes phycocyanin against heat and pH fluctuations.
• The improved properties of mPEG-PC facilitate its use in food and pharmaceutical applications.
• PEGylated phycocyanin offers enhanced functionality and bioactivity compared to native PC.