While walking home one day, Robert Graybosch found himself in what he describes as a philosophical mood. He was nearing the end of his career and wanted to use the remaining years he had as a research geneticist at the U.S. Department of Agriculture’s Agricultural Research Service to make an impact.
“I just thought to myself, ‘why not try to do something to alleviate at least one ill in the world?'’’ Dr. Graybosch said.
The subject of mineral nutrition crept into his mind as he knew little had been done on the subject, especially regarding wheat breeding. Dr. Graybosch recalled that about 60% of the world’s population doesn’t get enough iron because their food lacks essential minerals. And while fortification had made ingredients like flour more nutritious, he knew people were becoming increasingly hesitant about consuming products with artificial or unnatural sounding elements.
With these ideas and limitations in mind, Dr. Graybosch and his team set out to naturally enhance the minerals of wheat flours through biofortification. Over the next couple of years, they developed experimental breeding lines of winter wheat and tried to combine low phytate and high grain protein without lowering grain yield. Their results showed that combining the two traits without any negative effects on grain yield was possible and that it increased the amount of zinc, calcium, and manganese humans could get from the wheat.
In an interview with Baking & Snack, Dr. Graybosch discussed how biofortification could benefit consumers and enhance the nutritional characteristics of wheat.
Baking & Snack: What is biofortification? How does it differ from fortification?
Dr. Robert Graybosch: Biofortification is the process of naturally enhancing the nutritional value of a crop or food. It can be accomplished via traditional plant breeding using natural genetic variation, natural or induced mutations or via genetic engineering. If one found a mutation that resulted in higher grain iron concentrations, and one then bred this trait into a cultivar that was produced and consumed, then we could say the crop has been biofortified.
In our study, we combined an induced mutation that reduced phytic acid in the grain and a naturally occurring gene from a wild relative of wheat that was reported to elevate grain protein and perhaps increase iron and zinc. Phytic acid can chelate or bind essential minerals in the grain, preventing their absorption. It also binds nearly all the grain phosphorous, rendering it unavailable.
Our goal was to combine these two genes to see if we could improve the mineral availability of wheat grain. We did see some beneficial effects on grain mineral availability, and, simply by having lower phytic acid, we developed potentially more nutritious grain.
Fortification would be the addition of minerals or vitamins, post-harvest. As you know, the baking industry does this now for folic acid, niacin, iron and other factors of nutrition. Biofortification, in theory, could eliminate some of these additions, and it would be useful in developing nations where fortification is not common.
How is the process performed?
Dr. Graybosch: There are many reported attempts in the scientific literature using genetic engineering. This has the drawback of a lack of consumer acceptance, especially in wheat. To my knowledge, genetically engineered wheat has never been commercially produced in the U.S. Our approach was non-genetic engineering. We simply obtained previously characterized wheat breeding lines that had the two genes of interest and then cross mated them to produce progeny with both.
Are there any drawbacks or limitations to biofortification?
Dr. Graybosch: Well, that was one of the things we wanted to find out — would the low phytate trait reduce grain yield in Wheat Belt environments — and the answer was “no.” So, to the farmer, there is potentially no downside to growing a wheat cultivar with the traits we studied.
The limitation to the process, unfortunately, might be of a practical nature. With commodity crops such as wheat, it is very difficult, especially in the U.S., to produce and market a specialty wheat. There needs to be a financial incentive to the grower, and end-users would have to set up vertically integrated identity preserved markets.
This has been accomplished with a few wheat cultivars with specific processing traits, but the trait must be of large enough value to the miller or baker for either to commit. Market penetration could be a challenge, simply due to the manner in which wheat now is produced and marketed. In developing nations, there might actually be easier ways to get these wheats to the dinner table.
Can biofortification improve the quality of wheat?
Dr. Graybosch: Biofortification is used to address different aspects of quality — nutritional quality, rather than the functional quality of the flour. It could improve wheat nutritional quality perhaps by both increasing the concentration of essential minerals in the grain, and, by reducing phytic acid, increasing their absorption in the gut.
How could biofortified wheat benefit bakeries and their consumers?
Dr. Graybosch: It is potentially useful as people in many parts of the world do not consume a balanced diet, and their staple foods are mineral deficient. If one could naturally enhance mineral composition of wheat flours it would go a long way toward alleviating iron deficiency in the developed and developing worlds.
In developed nations, the situation can be addressed by fortification — the process of adding minerals back to food products. This is done with flours used for bread baking — food producers add iron powders, often as ferrous sulfate, to provide needed iron. This is fine and dandy, but some consumers are hesitant to consume products with what they perceive to be added chemicals. Biofortification might help achieve clean labels.
To read more about Dr. Graybosch’s study, click here.