White bread goes healthy?
It’s the best thing to happen to white bread since …well for a quite a while.
An international group of scientists led by Rothamsted Research and the John Innes Centre have opened the door to healthier white bread, after they pinpointed genes responsible for the dietary fibre content of flour.
They say this new white flour is otherwise identical and makes a good quality white loaf – but with all the added health benefits that come from eating wholemeal bread, including reduced cancer, diabetes and obesity risks.
The high fibre white flour they produced has as much as twice the fibre of traditional white flour
Writing in the journal PLOS ONE, lead author Dr Alison Lovegrove, Rothamsted Research, said the team had achieved the breakthrough by exploiting the results of an earlier genetic screen of over 150 different wheat varieties from around the world.
“We knew that the white flour made from one particular Chinese wheat variety, Yumai 34, was unusually high in fibre, but it’s not well suited for growing in the European climate,” she said.
“Using conventional breeding techniques, we crossed this high fibre trait into several other varieties. This allowed us to narrow down where in its genome the genes for high fibre are.”
Traditionally, crop varieties are improved by identifying plants with desirable traits and breeding from them. The problem with high fibre is it is not a trait you can identify by eye – and biochemical lab tests for it are slow and expensive.
“We’ve developed genetic markers that can easily be used by plant breeders to identify which individual wheat plants have the high fibre genes,” said Dr Lovegrove.“We hope to go on and identify further genes that increase fibre content, thereby providing plant breeders, millers and food producers with even more options.”
Most of the fibre found in wheat grain is in the bran – the part that is removed when producing white flour, and what differentiates it from wholemeal flour.
A slice of typical white bread has about 1g of fibre, whereas wholemeal has about 3g. A slice from a high fibre white loaf could contain up to 2g.
Government advice suggests adults should eat about 30g of fibre a day, but the average adult in the UK currently only eats about 18g.
Whilst wholemeal is widely regarded as being much better for us, white bread still outsells it, making up three quarters of the roughly 12 million loaves sold in the UK each day.
Taste, appearance, shelf life and price are the main reasons why consumers favour white bread, whilst the £8bn a year pre-packed sandwich industry prefers it as it refrigerates better.
The study was a collaborative project with researchers from Rothamsted, the John Innes Centre and the University of Bristol in the UK - who are all part of the BBSRC funded Designing Future Wheat programme – along with colleagues in Hungary, France and Turkey.