'Invisible fibre' boost for low-fibre food

Increasing the fibre content of food products by more than 10–20% while also maintaining pleasant taste and texture is a challenge across the food industry. Some foods with added fibre can have a tough texture or different flavour to the original product.

Now scientists have converted native starches, such as cassava, wheat and maize, to dietary fibre that can be added to foods to make them healthier without changing their texture, colour or taste.

Researchers at RMIT University worked with Microtec Engineering Group, a technology-based engineering company that supplies starch processing equipment, to develop the starch-based product, called FiberX, which resists digestion in the human gut, just like fibre.

Not only is FiberX smooth and tasteless, but it’s also suitable for fortifying low-calorie and low-GI foods and can be gluten-free, or for adding to low-fibre foods such as white bread, cakes, pasta, pizza and sauces to make them healthier.

The project lead from RMIT’s Food Research and Innovation Centre, Associate Professor Asgar Farahnaky, and his team used advanced starch modification technology with approved food-grade materials to create what is described as an ‘invisible fibre’.

“We can now add extra fibre to foods like white bread and other staples without changing the taste or texture, which has been one of the main issues with many commercially available fibre supplements to date,” he said.

“Our product is not even noticeable once added. It’s just like a parent hiding vegetables in a child’s meal to make it more nutritious.”

As part of the research, Farahnaky’s team conducted taste tests and texture analysis on bread and cakes with varying amounts of added FiberX. They found they were able to add up to 20% fibre to food while maintaining the original taste and texture of the product.

“This new technology means we can increase the amount of fibre that goes into the food so we can receive our recommended daily intake, even while consuming less foods, which has potential to help with weight management and diabetes,” he said.

How does it work?

Co-researcher and Vice-Chancellor’s Senior Research Fellow, Dr Mahsa Majzoobi, said the structure of starch was modified on a molecular level and tested to see how it reacted with digestive enzymes.

“Once the resistant starch goes through this process, it needs to have high levels of resistance to be counted as a successful conversion to dietary fibre,” she said.

Using this new technology, the team can convert more than 80% of starch into dietary fibre, Majzoobi said.

FiberX was tested using internationally approved methods at RMIT and the accredited Australian Export Grains Innovation Centre.

Associate Professor Asgar Farahnaky and Senior Research Fellow Dr Mahsa Majzoobi.

Farahnaky said his team are now looking at the next phase of FiberX technology, which will use green alternatives to convert starch to fibre.

Reducing food waste

Farahnaky said beyond the health benefits, FiberX technology also had the potential to improve supply-chain challenges and reduce food waste.

“Australia currently exports large amounts of grain for creating value-added products, such as plant-based meat. We then have to import these products back to Australia and wait for them if there are delays in the supply chain, as we saw with COVID,” Farahnaky said.

“Instead of growing and exporting more grains, we should be using existing grains to create value-added products here in Australia.”

To do this, Microtec and RMIT’s Food Research and Innovation Centre have also partnered with the Fight Food Waste Cooperative Research Centre to stop starch and fibre-rich by-products of plant protein production from going to waste.

Australia currently produces 5000 tonnes of pulse protein a year, which generates 30,000 tonnes of waste.

Farahnaky said by processing this waste into dry pulse starch, FiberX technology can convert the starch to fibre on a large scale.

“Not only will this partnership help reduce food waste on a massive scale, but it will lead to creating new premium food products that are high in dietary fibre,” he said.

With the help of Microtec, FiberX technology is now ready for the food industry to use for large-scale production of dietary fibre.

Image credit: iStock.com/mtreasure