pH-responsive conformational variations regulate the emulsifying properties of Coprinus comatus...

Area of Science:

• Food Science
• Biochemistry
• Materials Science

Background:

• Protein-polysaccharide complexes are valuable functional ingredients in food.
• Understanding their structure-property relationships is crucial for application development.
• Coprinus comatus (CCP) is a mushroom source of such complexes.

Purpose of the Study:

• To investigate the pH-driven structural and physicochemical changes in CCP.
• To elucidate the relationship between CCP conformation and its emulsifying functionality.
• To explore the potential of CCP as a responsive emulsifier.

Main Methods:

• Simultaneous extraction of protein-polysaccharide complex from Coprinus comatus.
• Microstructural analysis using electron microscopy.
• Physicochemical characterization (surface charge, hydrophobicity, solubility, zeta potential, viscosity).
• Fourier transform infrared spectroscopy (FTIR) for structural elucidation.

Main Results:

• CCP exhibited a beaded fiber network at its isoelectric point (pH 4.8).
• Microstructure transformed to globule-adhered flakes and porous lamellae with increasing pH.
• Structural changes correlated with enhanced emulsifying properties, increased hydrophobicity, and solubility.
• Alkaline pH resulted in smaller emulsion particle size and increased zeta potential and viscosity.

Conclusions:

• CCP's structure is highly sensitive to pH variations.
• These pH-induced conformational changes significantly improve emulsifying capabilities.
• CCP demonstrates potential as a tunable and responsive emulsifier for the food industry.