Added fibre: Why fortification is harder than it looks

Fibre formulation challenges overview for closing the fibre gap

• Adding fibre supports health goals but requires complex product reformulation
• Different fibres have varied solubility, viscosity and hydration affecting applications
• Excess fibre can cause processing failures, instability and shelf life issues
• Molecular properties determine fibre interactions with proteins, water and formulation stability
• Predictive, knowledge driven development improves efficiency and reduces costly reformulation risks

Adding fibre to popular food and beverage products could help to close the much-discussed ‘fibre gap’. And the success of high-protein products shows there’s clearly demand for this kind of nutritional upgrade

But you can’t just add extra fibre to a product and expect everything else to stay the same.

One fibre does not fit all

A key difficulty lies in the diversity of fibre itself. Fibres vary hugely in their functional characteristics. Some dissolve easily, others remain as particles. Some create structure and thickness, others don’t. And some hydrate quickly, while others continue to absorb water long after processing.

These differences have direct implications for formulation. A fibre that works in a beverage may completely fail in a dairy or bakery application. Liquid products need soluble, low-viscosity fibres, while structured products require carefully controlled thickening.

Constrained by functionality

These effects can be managed at today’s fibre levels. But they can quickly become problematic as levels increase.

For example, fibres that bind water are effectively already used as thickeners and stabilisers. But indiscriminately adding more of these fibres will lead to excessive viscosity and a formulation that is too thick to pump or mix. The formulation becomes impossible to process, and the product becomes unmanufacturable.

Problems may not always be apparent immediately. If the chosen fibre continues to hydrate over time, a product that appears stable in the factory may become unstable later in its shelf life – perhaps becoming too thick to use or even undergoing phase separation.

Choosing the right fibre isn’t just about nutritional and health benefits. Fibre’s functionality also needs to be matched to the requirements of the product.

A molecular perspective

The functional diversity of fibres stems from their molecular diversity. Fibres differ hugely in their molecular size and structure, which affects how they interact with water and other ingredients in a formulation.

For example, fibres can attract, repel or “ignore” protein molecules, which has a big impact on whether the product will be stable or not. Exactly how fibres and proteins interact is determined by molecular properties including charge, size, structure, solubility and hydration behaviour.

These properties don’t act in isolation, meaning fibres with similar compositions can behave very differently in application.

Moving beyond trial and error

All this means that increasing fibre isn’t just a minor formulation adjustment. It can involve a complete reformulation. And doing that efficiently requires something more systematic than traditional trial-and-error development.

Rather the industry should consider a more knowledge-driven and predictive approach. This starts with building a molecular-level understanding of fibres, analysing how they interact with water, proteins and other components rather than just testing outcomes. The analysis must go beyond standard supplier specifications and include properties such as hydration rates and viscosity development.

In this way, it will become possible to link molecular behaviour to product performance and predict how a specific fibre will affect texture, stability and processing in a given application. Manufacturers would then be able to create a short list of suitable fibres for faster, more focused product development.

The foundations are out there

The molecular behaviour of fibres hasn’t been fully studied. The industry will need to invest research resources to build up this understanding. But we aren’t starting from zero.

Basic structural and composition data for many fibres is already available. Supplier specifications and manufacturers’ benchmarking also provide basic but useful information.

There are also decades of research on areas such as protein-carbohydrate interactions and polysaccharide behaviour thanks to efforts to develop alternative-protein, low-fat or low-sugar products. Much of this work is framed as “carbohydrate behaviour”, but many of these carbohydrates are actually fibres.

This isn’t yet enough for full predictive power. But it is a good jumping-off point for further research.

From understanding to impact

Building this molecular understanding of fibres will help manufacturers develop added-fibre products faster and with less risk of costly reformulation failures. It will also enable products that deliver on taste and mouthfeel.

That matters because, whether they are trying to close the fibre gap or deliver targeted health benefits, added-fibre products will only be successful if consumers enjoy them. As such, understanding fibre is both a technical enabler and a commercial advantage.