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Shear-reversible and super-thickening starch Janus particles
Zoe Atkins1, Peilong Li1, Jieying Li1
1Department of Food Science, College of Agricultural and Life Sciences, Cornell University, Stocking Hall, Ithaca, NY 14853, USA.
Carbohydrate Polymers
|May 21, 2025
Summary
Fabricated Janus particles, featuring oppositely charged hemispheres, significantly enhance viscosity and shear resilience in starch-based materials. These novel particles offer potential as shear-reversible super-thickeners for food applications.
Area of Science:
- Materials Science
- Colloid Science
- Food Science
Background:
- Starch is widely used as a thickener in food products.
- Native starch can exhibit limitations in viscosity and shear stability.
- Developing modified starches with enhanced functional properties is of significant interest.
Purpose of the Study:
- To fabricate starch Janus particles with oppositely charged hemispheres.
- To investigate the impact of charge asymmetry on particle self-assembly and rheological properties.
- To evaluate the potential of these Janus particles as super-thickeners in food systems.
Main Methods:
- Utilized a 3D masking approach involving emulsification of amaranth starch granules onto oil droplets.
- Chemically modified the exposed surface of starch granules with 2,3-epoxypropyltrimethylammonium chloride (ETMAC) for cationic treatment.
- Characterized the Janus particles using X-ray photoelectron spectroscopy (XPS), confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM).
Main Results:
- Successfully created starch Janus particles with distinct positively and negatively charged hemispheres.
- Confirmed the presence of quaternary ammonium groups on the modified hemisphere via XPS, CLSM, and SEM.
- Observed self-assembly of Janus particles driven by electrostatic interactions, leading to particle aggregation.
- Achieved a remarkable 30-fold increase in viscosity compared to native starch (220 Pa·s vs. 6.70 Pa·s).
- Demonstrated shear-reversible properties, with viscosity recovery after shear disruption.
Conclusions:
- Starch Janus particles exhibit unique charge asymmetry, enabling self-assembly and significant viscosity enhancement.
- These particles possess superior thickening capacity and shear resilience compared to native starch.
- The shear-reversible nature and enhanced properties make starch Janus particles promising candidates for food applications as super-thickeners.
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