Ketchup, chilli sauce and mayonnaise look simple and are not. Each is a high-acid, high-solids, ion-rich system where the structure has to survive hot filling, months of storage and a consumer's expectations about how the product behaves on a plate. Gellan gum is used in all three, for slightly different reasons.
Ketchup: suspension and water control
Tomato ketchup is a concentrated tomato paste with sugar, salt, vinegar and spices, at roughly pH 3.7 and around 25–35 % solids. Tomato paste already supplies body, so the technical problems are not about thickness.
They are about stability:
| Problem | What the consumer sees |
|---|---|
| Water separation (syneresis) | Liquid on the surface in the bottle or on the plate |
| Pulp settling | A dense layer at the bottom, uneven colour |
| Poor cling | The product runs off rather than holding where it lands |
A small dose of low acyl gellan gum addresses the first two directly. Its weak gel network provides enough yield stress to hold the insoluble tomato solids in suspension and to hold water in the network, which reduces surface separation.
Typical dosage for this kind of effect is very low — often in the range of 0.02 % to 0.08 %, depending on the tomato solids and the rest of the stabiliser system. Because dosing is so low, ketchup is usually a blend: gellan gum for structure, and a cheaper viscosity builder such as starch or xanthan for body.
The formulation trap is the ion load. Tomato is naturally rich in potassium and contains calcium, and ketchup is heavily salted. All of that is already in the recipe before you add the gum. If you hydrate the gum in a phase that already contains the salt and the paste, it can gel prematurely and give an uneven batch. Hydrate first, add the ionic ingredients afterwards.
Chilli sauce and other particulate sauces
Chilli sauces, sambal, relish, salsa and similar products have a harder suspension problem than ketchup, because they contain visible, dense, irregular particles that must be held in a thin, low-viscosity liquid.
This is exactly the application gellan gum is best at. A weak gel network at 0.02–0.05 % will hold particulates that a thickener cannot, while keeping the sauce pourable — which matters, because a sauce that has to be shaken or stirred is a complaint generator.
Additional considerations for this category:
- High salt levels are normal, and they supply the cations the network needs. That is helpful, but it also means you cannot treat the ion balance as a free variable.
- High acid levels mean the gum must be hydrated before the acid is introduced, and the final pH must be verified against gelation performance.
- Heat treatment varies widely, from unpasteurised cold-filled products to hot-filled and retort-processed ones. Low acyl gellan gum's heat stability covers the full range, which is one reason it is preferred over starches in hot-fill applications.
Mayonnaise and emulsion sauces
Mayonnaise is an oil-in-water emulsion, and its stability depends on the emulsifier and on the viscosity and yield stress of the continuous phase. Two formulation trends have increased the role of hydrocolloids:
- Reduced-fat products, where less oil means less natural emulsion structure.
- Egg-free and vegan mayonnaise, where the emulsifier itself changes and the continuous phase has to carry more of the structural load.
Gellan gum contributes in two ways:
- Emulsion stability. Yield stress in the continuous phase slows droplet creaming and reduces water separation. In reduced-fat products this is often the difference between a stable product and one that separates in the jar.
- Structure at low dosage. A small amount can replace part of the starch or egg yolk solids that a traditional recipe uses for body, which matters for both cost and labelling.
The shear caveat is important here. Emulsification is a high-shear operation. If the gum has already gelled before or during emulsification, the network is destroyed and does not fully recover, leaving you with a product that is thinner than the laboratory sample. Hydrate and structure the aqueous phase first, then emulsify — and verify the final viscosity, not just the intermediate.
Comparison for these three categories
| Ketchup | Chilli / particulate sauce | Mayonnaise | |
|---|---|---|---|
| Primary gellan role | Water control, suspension | Suspension of visible particles | Emulsion stability, structure |
| Typical dosage | 0.02–0.08 % | 0.02–0.05 % | 0.05–0.15 % |
| Main challenge | High solids, high ions | High salt, high acid, high shear | High shear during emulsification |
| Usual blend partner | Starch or xanthan for body | Xanthan for viscosity | Starch for body |
The one process rule for all three
Hydrate the gellan gum in the water phase before the acid, the salt and the solids go in. Every failure described in this article traces back to that sequencing, or to insufficient hydration temperature.
What to ask a supplier
- What dosage do you recommend for syneresis control in a pH 3.7, 30 % solids tomato system?
- Which grade do you recommend for a hot-filled particulate sauce?
- Do you have data on suspension of dense particles at low viscosity?
- How does the material perform when the recipe's calcium comes from the vegetable component rather than an added salt?
For food-grade gellan gum (E418) with technical support for sauce and dressing applications, see Cinogel.
Part of the E418.org gellan gum knowledge base. See also: gellan gum in sauces and dressings, and gellan gum formula for sauce and dressing.