Technical Note #013: Stabilizers and Emulsifiers - Their Role in Ice Cream Structure

Introduction: Formulation Goes Beyond Mix Balancing

Formulating ice cream is not simply a matter of balancing sugars, fats, proteins and total solids. Even when these parameters are carefully controlled, the texture and stability of the finished product also depend on physical and physicochemical phenomena occurring during manufacturing, freezing and storage.

Water, fat and incorporated air are not merely a combination of ingredients. Together, they form a complex structure whose organization largely determines the characteristics of the ice cream: creaminess, firmness, resistance to melting and stability over time.

This is where stabilizers and emulsifiers play an important role. When properly selected and dosed, they help control the behaviour of the mix and achieve the desired structure.

However, their functions are different, and using them effectively requires an understanding of the mechanisms involved.

1. Stabilizers: Controlling the Behaviour of Water

Stabilizers used in ice cream production mainly belong to the hydrocolloid family. These substances interact with water and modify the rheological properties of the aqueous phase.

Their primary function is generally to increase and control mix viscosity. This modification influences water mobility and the behaviour of the mix throughout the different stages of production.

Their Role in Ice Cream Structure

Stabilizers contribute to:

• Increasing and controlling mix viscosity.

• Limiting water mobility within the aqueous phase.

• Reducing ice crystal growth and recrystallization during storage.

• Improving texture stability when exposed to temperature fluctuations.

• Contributing to mouthfeel and the creaminess of the finished product.

  
  

It is important to understand that stabilizers are not antifreeze agents. They do not replace sugars and do not directly determine the freezing point of the mix. Their action is mainly related to the properties of the aqueous phase and the structure of the product.

Controlling water in ice cream therefore relies on several complementary mechanisms: its proportion in the formulation, the fraction of water frozen at a given temperature, the properties of dissolved substances and the action of stabilizers.

Main Stabilizers Used in Ice Cream Production

There are many different hydrocolloids, whose properties vary according to their origin, molecular structure and conditions of use.

The most commonly used include:

Guar Gum

Extracted from guar seeds, it has a strong thickening capacity and helps increase the viscosity of the aqueous phase. It is frequently used to improve texture and limit water mobility.

Locust Bean Gum

Also known as carob bean gum, it is extracted from the endosperm of carob seeds. It has thickening properties and can develop interesting synergistic effects when combined with other hydrocolloids.

Xanthan Gum

Produced through bacterial fermentation, it has significant thickening power, even at low concentrations. Its particular rheological behaviour can contribute to mix stability.

Carrageenans

Extracted from red seaweed, carrageenans comprise several types of polysaccharides whose properties depend on their structure. They can interact with certain milk proteins and contribute to the stability of formulations.

Pectins

Naturally present in many fruits, pectins have thickening or gelling properties that vary according to their degree of esterification and the conditions of the surrounding medium. They are particularly useful in certain fruit-based formulations.

These ingredients are not interchangeable. Their effectiveness depends on their nature, concentration, hydration, temperature, pH and the overall composition of the mix.

2. Emulsifiers: Organizing the Interfaces Between Water and Fat

In dairy ice cream, fat is dispersed throughout an aqueous phase in the form of fat globules. This arrangement forms an emulsion: two phases that do not naturally mix are maintained in a dispersed state.

Milk proteins, particularly caseins, contribute to stabilizing the interface between fat and water.

Emulsifiers are molecules with a hydrophilic part, which has an affinity for water, and a lipophilic part, which has an affinity for fat. They can position themselves at the interface between these two phases and modify its properties.

A Specific Role During Freezing

In ice cream production, the objective is not necessarily to maintain the emulsion at maximum stability.

During whipping and freezing, controlled partial destabilization of the fat globules is desirable in ice creams containing fat. This phenomenon promotes fat globule aggregation and contributes to the formation of a partially coalesced fat network around the air cells.

This structure contributes to the body of the ice cream, its melting behaviour and its mouthfeel.

Emulsifiers can therefore help modify the behaviour of the fat phase and promote the formation of this structure.

It is important, however, to distinguish between emulsification and partial destabilization. These two phenomena are not contradictory; they occur at different stages and levels of the manufacturing process.

3. Stabilizers and Emulsifiers: Two Complementary but Different Functions

Although they are often combined in functional blends intended for ice cream production, stabilizers and emulsifiers do not act in the same way.

Stabilizers primarily affect the aqueous phase, viscosity and water mobility.

Emulsifiers primarily act at the interfaces between the aqueous and fat phases, modifying their behaviour.

Their combined action contributes to the organization of a complex structure made up of several elements:

• Ice crystals.

• Air cells incorporated during whipping.

• Fat globules and their aggregates.

• The concentrated aqueous phase containing sugars, proteins and other soluble components.

  
  

The final texture results from the interaction between these different elements. No stabilizer or emulsifier can, on its own, guarantee an ideal texture independently of the formulation and manufacturing process.

4. Selection and Dosage: Why More Is Not Always Better

The use of stabilizers and emulsifiers requires a considered approach. Their effectiveness depends on the complete formulation and production conditions.

An insufficient dosage may fail to provide the desired properties: inadequate viscosity, increased sensitivity to temperature fluctuations or a less stable structure during storage.

Conversely, excessive dosage can produce undesirable effects:

• A texture that is too thick or gummy.

• A sticky mouthfeel.

• Excessive mix viscosity.

• More difficult hydration and dispersion.

• Changes in whipping behaviour and final texture.

  
  

There is therefore no universal dosage applicable to every formulation.

A stabilizer must be selected according to its properties, but also according to the nature of the ingredients present in the mix and the desired result.

Combining several stabilizers can also be beneficial. Certain hydrocolloids exhibit synergistic effects: their combined properties may differ from those obtained when they are used separately.

However, these combinations must be carefully controlled, since using more functional ingredients does not necessarily improve the final result.

5. An Approach Adapted to Ice Cream and Sorbets

The requirements are not the same for dairy ice cream and fruit sorbets.

In ice cream, the presence of fat, milk proteins and a complex aqueous phase requires consideration of the interactions between these different components.

In sorbets, the structure consists mainly of water, sugars, soluble fruit components and, depending on the formulation, naturally occurring fibres and pectins.

The choice of stabilizer must therefore take into account the nature of the fruit, its water content, acidity, composition and the desired texture.

The use of an emulsifier must also be assessed according to the actual composition of the recipe. In a traditional sorbet containing no fat, the emulsification mechanisms described for dairy ice cream do not apply in the same way.

It is therefore essential not to automatically transfer a functional solution from one product category to another.

6. Gelato Pro Software: A Wide Range of Stabilizers and Emulsifiers

Mastering formulation also requires the ability to select functional ingredients suited to each recipe.

Gelato Pro Software includes a range of 19 stabilizers and 3 emulsifiers, allowing professionals to work with different functional solutions for their ice cream and sorbet formulations.

The software also allows users to select and combine up to two stabilizers in a single formulation.

This feature makes it possible to explore different hydrocolloid combinations and develop formulations suited to the desired characteristics, without unnecessarily increasing the number of ingredients.

The objective is not to propose one combination as systematically better than another, but to give formulators the ability to select functional ingredients according to the composition of the mix and the desired characteristics of the finished product.

This approach reflects the philosophy behind Gelato Pro: providing professionals with formulation and analysis tools that enable them to understand, control and optimize their recipes.

7. From Formulation to Production: The Importance of the Process

Even a carefully balanced formulation cannot, by itself, guarantee the final result.

The properties of stabilizers and emulsifiers also depend on manufacturing conditions.

Several stages are particularly important:

Incorporation and Dispersion

Ingredients must be properly dispersed to prevent the formation of aggregates and ensure uniform hydration of the stabilizers.

Heat Treatment

Depending on their nature, hydrocolloids require specific hydration conditions. Heat treatment can also modify interactions between proteins, stabilizers and other components of the mix.

Mix Ageing

This stage allows stabilizers to hydrate and, in mixes containing fat, enables partial crystallization of the fat phase. It therefore helps prepare the mix for freezing and whipping.

Whipping and Freezing

Air incorporation, ice crystal formation and partial fat destabilization all contribute to the development of the final structure.

Hardening and Storage

The hardening rate and temperature stability during storage play a decisive role in preserving the structure and limiting recrystallization.

These different stages demonstrate that ice cream quality depends as much on formulation as it does on control of the manufacturing process.

Conclusion: Texture Control Relies on Several Mechanisms

An ice cream that is chemically well balanced is not necessarily an ice cream with a perfectly structured physical composition.

Balancing sugars, fats, proteins and water provides an essential foundation for formulation. However, controlling texture also requires an understanding of the role of stabilizers and emulsifiers and their interactions with the different components of the mix.

The selection of functional ingredients, their dosage and their combinations must be adapted to each formulation and its production conditions.

Stabilizers and emulsifiers do not replace a properly balanced formulation. They are complementary tools that help professionals better control the structure, texture and stability of their ice creams and sorbets.

Formulation defines the product's potential. Controlling its structure and manufacturing process allows that potential to be fully achieved.