Comparison of different gum-based thickeners using a viscometer and line spread test: a preliminary study

Area of Science:

• Food Science and Technology
• Rheology
• Biochemistry

Background:

• Fluid thickeners are crucial in food and pharmaceutical industries for modifying texture and stability.
• Starch polysaccharide (STA), guar gum-based polysaccharide (GUA), and xanthan gum-based polysaccharide (XAN) are common thickeners with distinct properties.
• Understanding their rheological behavior under various conditions is essential for effective application.

Purpose of the Study:

• To compare the rheological properties of starch polysaccharide (STA), guar gum (GUA), and xanthan gum (XAN) based fluid thickeners.
• To evaluate the influence of different measurement conditions (concentration, shear rate, temperature) on thickener viscosity.
• To assess the correlation between viscometer measurements and line spread test (LST) results.

Main Methods:

• Viscosity measurements using a rotational viscometer at varying shear rates (1.29-103 s⁻¹) and temperatures (35°C).
• Exclusion of STA due to time-dependent viscosity alterations.
• Line spread tests (LST) conducted on GUA and XAN at different concentrations (1.5%-3.0%) and temperatures (20°C, 35°C).

Main Results:

• Viscosities of 1% GUA and XAN were similar, but differences increased with higher concentrations.
• Xanthan gum exhibited a more pronounced shear-thinning effect compared to guar gum.
• LST results showed no substantial differences between GUA and XAN, despite varying viscosities.

Conclusions:

• Fluid thickener viscosity is highly dependent on measurement conditions (e.g., shear rate, temperature, concentration).
• A single measurement method (viscometer or LST) may not be sufficient for comparing different thickeners.
• Clinical and industrial decisions regarding thickener selection require a comprehensive evaluation of rheological data and expert opinion.