Whey protein nanofibrils: the environment-morphology-functionality relationship in lyophilization, rehydration, and...

Area of Science:

• Food Science
• Biomaterials Science
• Rheology

Background:

• Amyloid-like fibrils from β-lactoglobulin show promise as thickening and gelling agents.
• Understanding the relationship between fibril morphology and bulk viscosity is crucial for optimizing their applications.

Purpose of the Study:

• To investigate the impact of lyophilization and rehydration on the morphology and rheological properties of straight and curly β-lactoglobulin fibrils.
• To correlate changes in fibril structure with alterations in viscosity.

Main Methods:

• Preparation of straight and curly β-lactoglobulin fibrils (curly fibrils prepared with 80 mM CaCl2).
• Lyophilization and subsequent rehydration of fibril dispersions.
• Morphological analysis of fibrils.
• Rheological measurements to determine bulk viscosity.

Main Results:

• Lyophilization and rehydration fractured straight fibrils into shorter rods, while curly fibrils remained largely intact.
• Rehydrated straight fibril dispersions exhibited significantly lower viscosities compared to curly fibril dispersions.
• Seeding new fibril growth with lyophilized fibrils did not substantially enhance viscosity, likely due to a balance between increased concentration and decreased length.

Conclusions:

• Fibril morphology significantly influences the rheological properties of β-lactoglobulin amyloid-like fibrils.
• Curly fibrils are more robust to lyophilization and rehydration, retaining higher viscosity.
• The findings provide insights into controlling fibril structure for effective thickening and gelling applications in food and biomedical fields.