The health-protective compounds in grains, in addition to dietary fibre, include folates, tocopherols and tocotrienols, other vitamins, trace elements and minerals as well as a range of phytochemicals such as lignans, phenolic acids, alkylresorcinols, phytosterols.
These compounds are concentrated in the outer layers of the grain such as the outer (bran) layer and the embryo (germ), but white flour which comprises most of the grain is made from starchy endosperm and is almost devoid of minerals.
So breeding wheat for mineral-enriched white flour requires developing varieties that deposit useable forms of minerals in the endosperm, and then being able to detect those minerals in the grain and this is where scientists from Rothamsted Research, an institute of Biotechnology and Biological Sciences Research Council (BBSRC), are getting involved.
They are using high powered x-rays to carry out fluorescence analysis instead of time consuming and limited traditional staining techniques to identify new wheat varieties in the hope of developing mineral rich white flour.
Lead researcher Andrew Neal told BakeryandSnacks.com that while there is high consumer awareness about the health benefits of eating wholegrain products, a preference still exists for baked goods using white flour and he said that research that can find a way to increase the iron and zinc quantities in white flour has huge potential.
Using a powerful microscope called a synchrotron, he said the team can locate several different minerals in grains simultaneously, and also provide information about their concentration, complexation (how the metallic elements are arranged) and digestibility.
He said that he is working in collaboration with grain researchers based at the University of Aarhus, under the EU Healthgrain initiative, who recently provided him with wheat lines that were developed to produce iron-rich endosperm.
However, Neal said that while measures of total iron in the grain indicated the lines contained as much as three times the amount of iron as traditional wheat grains, his x-ray analysis showed that much of the extra iron actually ended up residing in the bran and not in the endosperm.
“Our detection work here is essentially dependent on the Aarhus team successfully generating a variety of wheat that has high iron content in the endosperm, and once we get to that stage, it will be imperative to ensure that the transfer of iron into the endosperm does not result in a loss of other minerals such a zinc, nickel or manganese," he continued.
And he said that he believes that the fluorescence analysis method the team is using is the first technology that will provide those kind of answers.
Neal added that his research work in this area could potentially also be extended to allow for the analysis of an enriched white flour, once developed, as it goes through the various stages of production to ensure that mineral levels are not undermined by milling and processing methods.