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08:03
Study of Protein Dynamics via Neutron Spin Echo Spectroscopy
Published on: April 13, 2022
Slow dynamics and structure in jammed milk protein suspensions
Peggy Thomar1, Dominique Durand, Lazhar Benyahia
1LUNAM Université du Maine, IMMM UMR-CNRS, 72085 le Mans Cedex 9, France.
Faraday Discussions
|December 14, 2012
Summary
Dense sodium caseinate suspensions exhibit jamming and phase separation. Viscosity increases with protein concentration, while calcium ions induce attractive interactions, altering mechanical properties and leading to phase separation.
Area of Science:
- Food science and colloid chemistry.
- Protein physical chemistry.
- Rheology of soft matter.
Background:
- Caseins, the primary milk proteins, form nanoscale particles crucial for dairy product texture.
- Understanding casein suspension behavior is key to controlling food processing and product stability.
- Dense protein suspensions can exhibit complex rheological properties like jamming.
Purpose of the Study:
- To investigate the dynamic mechanical properties and structure of sodium caseinate suspensions.
- To determine the influence of protein concentration and temperature on suspension viscosity.
- To explore the effects of calcium ions on casein particle interactions and phase behavior.
Main Methods:
- Oscillatory shear rheology to measure dynamic mechanical properties.
- Confocal laser scanning microscopy to visualize particle structure and arrangement.
- Systematic variation of protein concentration, temperature, and calcium chloride (CaCl2) concentration.
Main Results:
- Viscosity significantly increases above ~80 g L(-1) protein concentration due to particle jamming.
- Higher protein concentrations and lower temperatures lead to increased viscosity and decreased terminal relaxation time.
- Calcium ions induce attractive interactions, causing phase separation above a critical concentration and altering rheological parameters.
Conclusions:
- Sodium caseinate suspensions exhibit jamming-driven viscosity increases and temperature-dependent rheology.
- Calcium addition promotes phase separation and modifies viscoelastic properties, with effects amplified at higher temperatures.
- These findings provide insights into the physical chemistry of milk proteins and their behavior in concentrated systems.
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