Burnt Toast

Source: Getty Images

UK scientists have used genome editing to develop a type of wheat that is less likely to produce acrylamide when baked.

The compound, which is classed as a possible carcinogen, forms during bread baking and its levels are increased when the bread is toasted – the darker the toast, the more acrylamide it contains. Other cereal-based products cooked at hot temperatures are also affected by the compound, along with chips and coffee. However, the amount of acrylamide in bread is relatively low.

A team led by Rothamsted Research with help from the University of Bristol have used a new technique of genome editing to develop the wheat. According to project leader Professor Nigel Halford, the researchers are preparing an application to the UK government to run a field trial. Starting in the autumn, it’s the first such trial of genome edited wheat to be carried out in Europe.

“We’ve used genome editing to reduce the amount of the amino acid, asparagine, in the grain. It’s the asparagine that is converted to acrylamide during baking and toasting, so a low asparagine wheat should lead to lower levels of acrylamide, which is good news for anyone who likes their toast well done,” said Sarah Raffan, the lead researcher on the field trial.

The field trial would not only examine the wheat in terms of asparagine concentration, but also the yield, protein content and other quality traits, Halford noted.

“If it comes through the field trial well it could be made available to wheat breeders. Even so, it would be another five to 10 years before very low asparagine wheat could appear on the market, and that would only be if the regulatory framework were conducive,” he said.

Professor Nigel Halford and Sarah Raffan with wheat plants

Source: Rothamsted Research

Professor Nigel Halford and Sarah Raffan with wheat plants

Barriers to rollout

The genome editing technique used, which is called CRISPR/Cas9, leads to small changes in the DNA, such as the deletion or insertion of short sections of DNA, or changes to the DNA sequence, in this instance halting the function of a gene involved in the production of asparagine.

It differs from the GM approach in that it doesn’t involve the introduction of novel, foreign or additional genes, the researchers said, adding that the sorts of changes to the wheat DNA are like those that occur naturally.

Despite the differences between genome editing with CRISPR/Cas9 and GM, genome edited plants are currently treated in the same way as GM under EU regulations, essentially blocking the use of a technology that is gaining official approval in many other parts of the world, they added.

The hope is that the current UK government consultation on this issue will lead to new legislation in the UK, allowing genome edited food products, carefully regulated, to be available to consumers.

Alternative solutions

Food businesses had to put in place steps to manage acrylamide under EU laws that came into effect in 2018. The rules established best practice, mitigation measures and benchmark levels for the reduction of acrylamide in food.

Following this, a dedicated laboratory was set up by Reading Scientific Services (RSSL) to meet rising demand for testing. RSSL developed a bespoke method of acrylamide detection as part of this.

Solutions to reduce acrylamide have also been rolled out, including a yeast enzyme called Acryleast from Kerry which is described as a clean-label, non-GMO product that can reduce acrylamide by up to 90% in products such as biscuits and crackers.

“A number of methods for reducing acrylamide in food products by changing processing methods have been developed. Some have been successful, but they are not applicable to all food types, are often expensive to implement and may have detrimental effects on product quality,” added Halford.

“The food industry would therefore benefit from the availability of raw materials with lower acrylamide-forming potential, and the determining factor for acrylamide formation in products made from wheat and rye grains, and probably those of other cereals, is the concentration of soluble (non-protein) asparagine.”