Flow behaviour of gellan sol with selected cations.

Area of Science:

• Food Science and Technology
• Materials Science
• Rheology

Background:

• Understanding the pre-gelation flow behavior of sols is crucial for designing nutrient-enriched gels.
• Gellan gum is a polysaccharide used in food and pharmaceutical applications, and its rheological properties influence gel formation.

Purpose of the Study:

• To investigate the impact of calcium chloride (CaCl2) and iron sulfate (FeSO4) on the rheological properties of gellan sols.
• To determine how cation type and concentration affect the viscosity and flow behavior of gellan sols before gelation.

Main Methods:

• Rheological measurements were performed on 1% gellan sols with varying concentrations of CaCl2 and FeSO4 (0.05% and 0.1% w/w).
• Apparent viscosity was measured at a shear rate of 100 s⁻¹.
• The Cross and Power Law models were used to fit the rheological data.

Main Results:

• Gellan sols with added cations exhibited higher apparent viscosity compared to cation-free sols.
• The Cross model provided a superior fit to the rheological data (0.97 ≤ r ≤ 0.99).
• Zero-shear viscosity (ηo) and relaxation time (λ) increased with the addition and concentration of CaCl2 and FeSO4, indicating enhanced solid-like characteristics.

Conclusions:

• Cation addition, particularly FeSO4, significantly enhances the viscosity and viscoelastic properties of gellan sols.
• The findings provide valuable insights for controlling the texture and stability of gellan-based gel systems.
• Optimizing cation content is essential for tailoring the flow behavior and gelation properties of nutrient-enriched gels.