High-moisture extrusion of curdlan: Texture and structure

Area of Science:

• Food Science and Technology
• Materials Science
• Biopolymer Engineering

Background:

• High-moisture extrusion is key for plant-based meat analogues, but polysaccharide applications are underexplored.
• Curdlan, a microbial polysaccharide, offers potential for novel food structures.

Purpose of the Study:

• To investigate the impact of extruder barrel temperatures on curdlan extrudate texture and structure.
• To elucidate the formation mechanism and phase transitions of curdlan during extrusion.

Main Methods:

• High-moisture extrusion with varying barrel temperatures (130°C-200°C).
• Analysis of texture, mechanical properties, crystallinity, and microstructure.
• Differential scanning calorimetry (DSC) for thermal analysis.

Main Results:

• Curdlan single chains aggregated into triple-helix structures, increasing crystallinity, especially at 170°C.
• Mechanical properties (hardness, chewiness) improved with temperature.
• Three distinct phases observed: original gel, transition state (melting at 160°C), and regenerated gel (170°C-200°C).

Conclusions:

• Extrusion temperature significantly influences curdlan gel structure and properties.
• 170°C represents a steady state for regenerated curdlan gel with enhanced crystallinity and network integrity.
• Findings provide insights for polysaccharide-based extrusion in food applications.