How Does Gellan Gum Control Particle Movement in Liquid Foods?

Gellan gum can control the movement of suspended particles in liquid foods by creating a weak internal structure within the continuous liquid phase. This structure can slow sedimentation and separation without requiring the entire product to become highly viscous.

Why do particles move in liquid foods?

Particles suspended in a liquid are constantly affected by gravity and the physical properties of the surrounding liquid.

If a particle is denser than the liquid, gravity tends to pull it downward. This produces sedimentation.

If a particle is less dense than the liquid, it may move upward and produce creaming or floating.

Particle movement is affected by several factors, including:

• Particle density
• Liquid density
• Particle size
• Liquid viscosity
• Particle shape
• Interactions between particles
• Internal structure of the liquid

A formulation therefore needs more than simply a thick liquid to maintain a stable particle suspension.

How does gellan gum slow particle movement?

Gellan gum can form a weak, three-dimensional structure throughout the liquid.

This structure increases the resistance experienced by moving particles.

Instead of moving freely through a simple liquid, particles have to move through or around the structured regions created by the hydrocolloid.

The result is a lower rate of particle movement.

This is particularly useful when the product needs to remain relatively fluid rather than becoming a thick paste.

Does gellan gum simply increase viscosity?

Not exactly.

A conventional thickener mainly slows particle movement by increasing the viscosity of the continuous liquid phase.

Gellan gum can provide another mechanism: a weak internal network or fluid-gel structure that restricts particle movement.

This distinction is important because a product can have relatively low apparent viscosity while still having significant resistance to sedimentation.

The goal is therefore not necessarily to make the entire liquid thick. It is to create enough internal structure to keep particles distributed.

What is the relationship between particle size and sedimentation?

Particle size has a major effect on sedimentation.

Under simplified conditions, the settling velocity of a small spherical particle in a Newtonian liquid can be described by Stokes' law:

v = 2r²(ρp − ρl)g / 9η

where:

• v is settling velocity
• r is particle radius
• ρp is particle density
• ρl is liquid density
• g is gravitational acceleration
• η is liquid viscosity

The equation shows that particle size has a particularly strong influence on settling velocity because the radius is squared.

This means that reducing particle size can significantly reduce the rate of sedimentation.

However, real food systems are usually more complicated than the ideal conditions assumed by Stokes' law.

Why is particle size important when using gellan gum?

Gellan gum does not eliminate the physical forces acting on particles.

If particles are very large or have a large density difference from the liquid, a stronger internal structure may be required to maintain suspension.

Smaller particles are generally easier to keep suspended because their gravitational settling tendency is lower.

Therefore, optimizing particle size and gellan gum structure together can be more effective than simply increasing gellan gum concentration.

Does particle density matter?

Yes.

The larger the density difference between a particle and the surrounding liquid, the stronger the gravitational driving force for separation.

For example, a dense mineral particle may settle more readily than a low-density plant particle under otherwise similar conditions.

Gellan gum can slow this movement by providing internal resistance, but the required formulation depends on the characteristics of the particles.

Can gellan gum prevent sedimentation completely?

Not necessarily.

A well-designed gellan gum system can greatly reduce the rate of particle movement, but complete immobilization is not always desirable or achievable.

A food or beverage may need to remain pourable and recover its uniform appearance after shaking.

The formulation therefore often aims for controlled suspension rather than permanent immobilization.

What is the difference between suspension and immobilization?

A stable suspension does not necessarily mean that particles never move.

Instead, the goal is usually to slow particle movement sufficiently that visible separation does not occur during the intended shelf life.

This distinction is important in beverage formulation.

If the internal structure is too weak, particles may settle quickly.

If the structure is too strong, the product may become excessively thick or develop an undesirable gel-like texture.

The ideal formulation provides enough structure to control particle movement while preserving the required flow behavior.

How does gellan gum help with low-viscosity beverages?

Low-viscosity beverages present a particular formulation challenge because particles can move relatively easily through the liquid.

Increasing viscosity with a conventional thickener can reduce sedimentation, but it may also produce an undesirable mouthfeel.

Gellan gum can instead create a weak internal structure that provides resistance to particle movement at relatively low use levels.

This makes it useful when suspension is required but a heavy or highly viscous texture is not acceptable.

How does fluid gel contribute to particle suspension?

A fluid gel contains dispersed gel structures within a continuous liquid phase.

These structures can create a physical environment that restricts particle movement.

The particles do not necessarily need to be trapped inside a rigid gel. Instead, their movement can be slowed by the weak structured environment surrounding them.

This allows the product to remain flowable while providing improved suspension.

Can gellan gum keep different types of particles suspended?

Potentially, yes, but performance depends strongly on particle characteristics.

Examples of suspended materials can include:

• Cocoa particles
• Fruit particles
• Plant particles
• Mineral particles
• Pulp
• Insoluble flavor components
• Other food particulates

Different particles have different sizes, shapes, densities, and surface properties.

Consequently, a formulation optimized for one type of particle may not provide the same suspension performance for another.

Why can particles still settle even when gellan gum is present?

Several factors can cause continued sedimentation.

The gellan gum structure may be too weak for the particle characteristics, or the particles may be too large or too dense.

Other possible causes include:

• Insufficient gellan gum hydration
• Unsuitable ionic conditions
• Incorrect processing conditions
• Excessive particle size
• Large density difference
• Incompatible formulation ingredients
• Breakdown of the internal structure during processing
• Long storage time

Simply adding more gellan gum is therefore not always the best solution.

Can particles float instead of settling?

Yes.

Particles with a density lower than the surrounding liquid can move upward rather than downward.

This is often called creaming or flotation.

The same basic principle applies: gellan gum can increase resistance to particle movement and slow separation.

However, the formulation may require a different strategy depending on particle density, size, shape, and surface properties.

How does gellan gum affect particle movement during storage?

During storage, even a small difference in particle movement can become visible over time.

A formulation that appears stable immediately after production may develop a sediment layer after weeks or months if the internal structure is insufficient.

Long-term stability testing is therefore important.

The relevant question is not only:

"Does the product suspend particles immediately?"

It is also:

"How slowly do the particles move during the intended shelf life?"

Does shaking restore a settled product?

Sometimes.

A formulation may be designed so that particles settle slowly during storage but can be redistributed by normal shaking before consumption.

This can be preferable to creating a rigid structure that permanently immobilizes the particles.

The ideal behavior depends on the product.

Some beverages require long-term suspension without shaking, while others are intentionally designed as shake-before-use products.

How does gellan gum compare with a conventional thickener for suspension?

A conventional thickener mainly increases the viscosity of the continuous phase.

Gellan gum can provide a structured suspension environment at relatively low concentration.

This difference can be summarized as:

Approach	Main mechanism	Typical effect
Conventional thickener	Increases continuous-phase viscosity	Slows particle movement by making the liquid thicker
Gellan gum	Creates internal structure	Restricts particle movement while maintaining flow
Fluid-gel system	Dispersed gel structures	Provides suspension with relatively low bulk viscosity

The best choice depends on the desired texture and stability of the final product.

What formulation factors should be considered?

Particle suspension should be evaluated as a complete system.

Important variables include:

1. Particle size
2. Particle density
3. Particle shape
4. Particle concentration
5. Liquid density
6. Gellan gum concentration
7. Gellan gum type
8. Mineral ion concentration
9. pH
10. Total soluble solids
11. Other hydrocolloids
12. Heating and cooling conditions
13. Shear history
14. Storage temperature

Changing one variable can alter the performance of the entire system.

Why is viscosity measurement alone not enough?

A viscosity measurement describes how the liquid responds under a particular test condition.

It does not necessarily predict long-term particle stability.

Two products can have similar measured viscosity but very different sedimentation behavior because their internal structures are different.

For this reason, suspension testing should ideally include both rheological measurements and actual storage observations.

How should suspension stability be tested?

A practical evaluation can include:

• Visual observation during storage
• Sediment height
• Sedimentation rate
• Supernatant clarity
• Particle redistribution after shaking
• Viscosity
• Flow behavior
• Temperature stability

Testing should be performed under realistic storage conditions and for a period representative of the intended shelf life.

Key takeaway

Gellan gum controls particle movement primarily by creating internal structure that increases resistance to particle motion.

Its function is not simply to make the liquid thicker.

Particle size, density, formulation chemistry, ionic conditions, processing history, and the strength of the internal structure all determine suspension performance.

For low-viscosity foods and beverages, the objective is usually to find the minimum structure required to slow particle movement while preserving the desired flow and mouthfeel.

Frequently Asked Questions

How does gellan gum suspend particles?

Gellan gum can form a weak internal structure that increases resistance to particle movement, slowing sedimentation or flotation while allowing the product to remain relatively fluid.

Does gellan gum increase viscosity?

It can increase viscosity, but its suspension effect is not solely due to bulk viscosity. Its internal structure can provide significant resistance to particle movement even at relatively low concentrations.

Why do particles settle in beverages?

Particles settle when their density is greater than the surrounding liquid and gravity causes them to move downward. Particle size, density difference, and liquid properties all influence the settling rate.

Does smaller particle size improve suspension?

Generally, yes. Smaller particles have a lower gravitational settling tendency under otherwise similar conditions.

Can gellan gum stop sedimentation completely?

Not always. The objective is usually to slow particle movement enough to maintain acceptable stability during the intended shelf life.

Why can particles still settle after adding gellan gum?

The internal structure may be insufficient for the particle size or density, or the gellan gum may not have developed the intended structure because of formulation or processing conditions.

Can gellan gum prevent particles from floating?

It can slow upward movement as well as downward sedimentation by increasing resistance to particle movement.

Is gellan gum better than a thickener for suspension?

Not universally. Gellan gum can provide suspension with relatively low bulk viscosity, which is useful in some applications, but the appropriate hydrocolloid depends on the product requirements.

Does fluid gel help suspend particles?

Yes. A fluid-gel structure can provide a weak internal network that slows particle movement while maintaining a flowable product.

Is viscosity enough to predict suspension stability?

No. Viscosity is only one part of suspension behavior. Internal structure, particle properties, and storage conditions also need to be considered.

What is the most important factor for particle suspension?

There is no single factor. Particle size and density, gellan gum structure, ionic conditions, processing, and the properties of the liquid all work together to determine stability.

Summary

Particle suspension in liquid foods is controlled by the balance between gravitational forces acting on particles and the resistance provided by the surrounding liquid structure.

Gellan gum can improve suspension by creating a weak structured environment that slows particle movement without requiring a highly viscous product.

Successful suspension therefore depends on more than gellan gum dosage. Particle characteristics, formulation chemistry, processing conditions, and long-term storage behavior must all be considered together.