Structural Transitions of β-lactoglobulin Aggregates Observed Under Controlled Heat Treatment

Area of Science:

• Protein chemistry
• Biomolecular self-assembly
• Food science

Background:

• Beta-lactoglobulin (β-Lg), a major whey protein, forms amyloid fibrils under acidic and thermal stress.
• Understanding β-Lg's structural transitions is crucial for food processing and biomaterial applications.

Purpose of the Study:

• Investigate the influence of different thermal conditions on β-Lg aggregation and fibrillation at pH 2.
• Determine how heating methods affect the structural changes and self-assembly pathways of β-Lg.

Main Methods:

• Subjected β-Lg solutions to stepwise, cyclic, and constant heating regimens at pH 2.
• Utilized fluorescence spectroscopy, Thioflavin T assay, CD, FTIR, FE-SEM, and AFM for structural and morphological characterization.

Main Results:

• Stepwise heating promoted amyloid fibril formation.
• Constant heating at 90°C induced extensive aggregation and highly ordered, β-sheet-rich fibrils.
• Cyclic heating/cooling resulted in reduced fibrillation, partial retention of native structure, and distinct aggregate morphologies.

Conclusions:

• Thermal treatment critically influences the balance between protein structural rearrangement and aggregation.
• Controlled thermal cycling modulates aggregation pathways, stabilizing intermediates and limiting highly ordered amyloid formation.
• Findings offer insights into thermal regulation of β-Lg aggregation for food and biomaterial applications.