Transglutaminase in vegan products – improved texture for modern plant-based applications

Vegan foods have long since evolved from a niche product into an integral part of the international food market. However, consumers today expect far more than simply a ‘plant-based’ label. Whether it is a meat alternative, a cheese alternative, a yoghurt alternative or a high-protein convenience product – texture, mouthfeel and sensory quality are crucial to a product’s success.

This is precisely where many manufacturers face a challenge. Plant-based proteins do not automatically possess the functional properties of animal proteins. They often lack stability, elasticity, water-binding capacity or the desired firmness when cut.

Transglutaminase can help to selectively cross-link plant proteins, thereby improving their functional properties. The enzyme is used in numerous food applications worldwide and offers interesting opportunities for structural optimisation, particularly in protein-based plant-based products.

Animal proteins such as casein, whey protein and muscle proteins naturally possess functional properties that are responsible for structure, water-binding capacity and stability.

Plant-based proteins, on the other hand, differ significantly in terms of their functionality. In addition to the source of the protein, manufacturing processes, purity and particle size play a decisive role.

Typical challenges associated with plant-based products include:

• brittle or excessively soft structures
• a dry or sandy sensation in the mouth
• Water loss (syneresis)
• inadequate water retention
• unstable emulsions
• insufficient cut resistance
• A lack of bite in meat alternatives
• Loss of structural integrity during processing and storage

That is why simply choosing a plant-based protein is often not enough. What matters is the interplay between the protein source, functional ingredients, processing methods and the desired end product.

Transglutaminase is an enzyme that can form covalent bonds between certain amino acids within proteins. This results in more stable protein structures, which can have a positive effect on the texture of many foods.

Under suitable conditions, the following effects, amongst others, may occur:

• improved water-binding capacity
• greater shear resistance
• more elastic textures
• reduced crumbiness
• more stable emulsions
• improved dimensional stability
• lower cooking loss
• more homogeneous product structure

However, the actual effect always depends on the specific formulation, the protein content and the process conditions.

In the development of plant-based foods, pea protein has established itself as one of the most important sources of protein, particularly in meat alternatives. The reasons for this are its good functionality and the advantage that, unlike soya or wheat protein, pea protein is not classified as a major allergen subject to labelling requirements.

In practice, however, it is evident that the effect of transglutaminase does not depend solely on the source of the protein.

Equally important are:

• Degree of protein purity
• Particle size
• Manufacturing process
• Degree of denaturation
• Solubility
• Protein concentration

Our practical experience has shown that different grades of the same pea protein can sometimes produce significantly different results. The fineness of the protein, in particular, can have a considerable influence on enzyme activity.

Finer protein fractions have a larger specific surface area, which means that more protein is available for the cross-linking reaction. In many applications, this allows for the formation of firmer, more homogeneous and more stable structures than is possible with coarser protein fractions.

For this reason, development trials should not be carried out solely by varying the transglutaminase dosage. It is often worthwhile simply to compare different protein qualities of the same raw material.

A common misconception is to regard protein content and specifications as the sole criteria for quality.

In practice, we regularly observe that two pea proteins with comparable protein content can yield completely different results.

Possible causes include:

• Differences in particle size
• Differences in solubility
• Thermal stress during manufacture
• Residual starch content
• Differences in fibre content
• Variations in protein structures

For this reason, the selection of a suitable protein should always be carried out in conjunction with an assessment of the enzyme’s activity.

Meat alternatives are among the most important areas of application for transglutaminase.

Consumers expect the following:

• succulent textures
• a pleasant bite
• easy to cut
• stable structure after heating
• authentic mouthfeel

Typical applications include:

• vegan cooked sausage
• alternatives to cold cuts
• burger patties
• nuggets
• plant-based moulded products
• hybrid products with a reduced meat content

The cross-linking of plant proteins can result in more compact and stable structures. At the same time, water-binding capacity can often be improved, which can have a positive effect on juiciness and yield.

When it comes to plant-based cheese alternatives, texture and workability play a key role.

Depending on the product concept, different properties are required:

• Cut resistance
• Dimensional stability
• Elastic structure

• mechanical stability
• reduced susceptibility to breakage
• consistent processing

• Creaminess
• Uniformity
• Stable water-binding capacity

In protein-based cheese alternatives, transglutaminase can help to stabilise the protein matrix in a targeted manner and adjust the desired textural properties.

One of the most common challenges with plant-based yoghurt alternatives is syneresis.

In the process, water separates from the actual product matrix and visibly collects on the surface. Consumers often perceive this as a quality issue.

Under the right conditions, transglutaminase can help to:

• to bind water more effectively
• to stabilise the gel structure
• to improve creaminess
• to increase viscosity
• to improve storage stability

Key factors influencing this are:

• Source of protein
• Fermentation process
• pH value
• Heat treatment
• Protein content

Convenience products place particularly high demands on the stability of a recipe.

Products are often:

• frozen
• heated
• re-heated
• transported
• stored for a long period

Typical applications include:

• plant-based ready meals
• snacks
• fillings
• breaded products
• frozen foods
• high-protein ready meals

Transglutaminase can help to reduce structural loss during processing and achieve a more consistent product quality.

Transglutaminase is a powerful tool in food technology, but it is no substitute for a well-designed recipe.

The effect may be reduced in the following cases:

• very low protein content
• unsuitable protein sources
• highly acidic systems
• very high fat content
• unfavourable process conditions
• reaction times that are too short

In many cases, the best results are only achieved when combined with other functional components.

In practice, it is rarely a single raw material that determines a product’s success.

Depending on the application, the following are often used in addition:

• plant fibres
• functional dietary fibres
• hydrocolloids
• starch products
• vegetable oils
• emulsifiers

The aim is to develop a stable overall formulation with reproducible properties.

The following factors are particularly relevant to the successful use of transglutaminase:

Parameter	Effect on the outcome
Dosage	Intensity of cross-linking
Protein content	Number of available binding sites
Temperature	Reaction rate
pH	Enzyme activity
Reaction time	Structural development
Salt content	Protein functionality
Fat content	Matrix formation
Heat treatment	Enzyme inactivation

The optimum setting should always be determined through practical trials.

Our research and development work with pea protein, field bean protein and various functional fibre blends consistently shows that the effect of transglutaminase depends heavily on the quality and processing of the raw materials used.

Particularly in high-protein formulations, significant improvements in water-binding capacity, cut-holding strength and texture can often be achieved. At the same time, practical experience shows that even variations in protein quality within the same raw material can lead to considerable differences in the end product.

Successful product development is therefore not based solely on the choice of an enzyme, but on the interplay between the protein source, functional ingredients and process control.

Transglutaminase offers manufacturers of plant-based foods interesting opportunities to specifically improve the functional properties of plant proteins.

Particularly in meat alternatives, cheese alternatives, yoghurt alternatives and convenience products, it can have a positive impact on stability, water-binding capacity, cut-resistance and mouthfeel.

However, the key to success lies in finding the right combination of protein source, functional ingredients and process parameters. Applications should therefore always be tested and optimised on a product-specific basis.

Are you developing a plant-based formulation or looking to improve the texture of your vegan products?

Our application engineering team can assist you in selecting suitable transglutaminase systems and in optimising your formulation and process.

Request a sample or speak to our experts about your project.