Why Does Gellan Gum Sometimes Lose Gel Strength After Storage?

Content:

A gellan gum gel can look perfect on day one.

Then a week later, something has changed.

Maybe it is softer.

Maybe water has started separating from the gel.

Maybe the texture has become more brittle.

Or the gel simply doesn't look the same anymore.

Why?

A gel is not necessarily a completely static structure.

Its properties can change during storage.

Fresh Gel vs Stored Gel

One of the most common mistakes in formulation testing is evaluating a gel only a few hours after preparation.

That tells you how the gel behaves when fresh.

It doesn't necessarily tell you how it will behave after:

• 1 day

• 1 week

• 1 month

• Several months

For a commercial product, storage stability can be just as important as initial gel strength.

What Is Syneresis?

If you see liquid separating from the gel, you may be seeing syneresis.

In simple terms, the gel network contracts and releases some of the water that was previously held within the structure.

You might see a layer of liquid around the gel.

This is obviously undesirable in many food products.

Why Can Syneresis Happen?

There isn't one single cause.

Possible factors include:

• Gellan gum concentration

• Gellan gum type

• Mineral content

• pH

• Other hydrocolloids

• Heating conditions

• Cooling conditions

• Storage temperature

• Freeze-thaw conditions

The complete formulation matters.

Can Too Much Gellan Gum Cause Problems?

Yes.

More gellan gum doesn't always mean a more stable product.

A very strong network can sometimes produce an undesirable texture or contribute to water release depending on the system.

This is why formulation should focus on the right structure rather than maximum gel strength.

What About Calcium?

Calcium can have a strong effect on gellan gum structure.

If the mineral balance changes during formulation or production, the final gel can change too.

This is particularly important when comparing different water sources or raw material suppliers.

Don't look only at the amount of gellan gum.

Look at the entire ionic environment.

Temperature Matters

Storage temperature can affect gel behavior.

A product stored at room temperature may behave differently from one stored under refrigeration.

Temperature cycling can be even more challenging.

For example:

Cold → warm → cold

may produce a different result from constant-temperature storage.

What About Freezing?

Freezing can be particularly harsh on hydrocolloid gels.

Ice formation changes the distribution of water and can damage the original structure.

After thawing, the gel may not return to exactly the same condition.

If a product may experience freezing during transport or storage, freeze-thaw testing should be considered during development.

Does pH Change During Storage?

It can.

Some formulations contain ingredients that slowly change the chemical environment over time.

If the pH changes significantly during storage, the gellan gum system may change as well.

This is why it can be useful to record pH during stability testing rather than checking it only at the beginning.

Why Can Two Gellan Gum Grades Behave Differently?

High acyl and low acyl gellan gum produce different gel structures.

HA generally produces softer and more elastic gels.

LA generally produces firmer and more brittle gels.

Their storage behavior can therefore also be different depending on the formulation.

The choice should be based on the final product requirements, not only initial gel strength.

How Should You Run a Stability Test?

Keep it simple and consistent.

Prepare several samples from the same batch.

Store them under defined conditions.

Then evaluate them at fixed time points.

For example:

Day 0

Day 1

Day 7

Day 14

Day 30

For longer shelf-life products, continue the test as needed.

What Should You Measure?

Don't only look at the gel.

Record:

• Appearance

• Gel strength

• Texture

• Syneresis

• pH

• Viscosity

• Clarity

• Sedimentation

• Separation

Photographs can also be surprisingly useful.

A photo taken under the same lighting and from the same angle can make small changes much easier to spot.

Don't Change the Test Conditions

If you test one sample at 20°C and another at 25°C, the comparison becomes less useful.

Try to keep:

• Temperature

• Sample size

• Container

• Measurement method

• Testing time

consistent.

Otherwise, you may be measuring the test conditions rather than the actual storage change.

What If the Gel Gets Stronger?

Not every change is negative.

Some systems can continue to develop structure after the initial setting period.

So if the gel becomes firmer during storage, that is also useful information.

The important question is whether the change is acceptable for the product.

A Practical Development Rule

Don't optimize a formulation only for day-one performance.

A formula that gives an excellent gel immediately but becomes unstable after two weeks is not necessarily a successful formula.

Sometimes a slightly weaker initial gel gives much better long-term stability.

That can be the better commercial choice.

The Bottom Line

When developing a gellan gum product, the question isn't just:

"How strong is the gel today?"

A better question is:

"How will this gel behave after storage?"

Check the formulation over time, control the storage conditions and pay attention to pH, minerals, temperature and processing.

A good gellan gum formulation should not only work when you make it.

It should keep working when the customer actually uses it.