TRADE & MARKETS
Bread & butter or pasta & sauce?
By Scott A. Yates
When it comes to wheat, the words “hard” and
“soft” refer to the kernel’s milling characteristics.
Soft white wheat, as its name would suggest, has
a soft kernel trait making it among the easiest of
all classes to mill. On a scale of kernel hardness, it
comes in at between a 25 and 35. Hard red wheat,
meanwhile, comes in at 60 to 75 on the same index.
Durum wheat, however, is in a class of its own. The hardest of all wheat classes, it ranks at nearly 80 to 100 on the hardness index. As a result, specialty mills specifically set up to grind durum generally don’t bother making flour because of the additional energy output, producing instead what is called semolina, a gritty product resembling coarse sand in texture that is used to make pasta, couscous and other foods.
There is no reason for the durum kernel to be so hard, said Craig Morris, director of the Agricultural Research Service’s Western Wheat Quality Lab in Pullman. It’s simply an evolutionary happenstance. So, is it possible to convert durum from an extremely hard kernel to something as soft as soft white? And why would you? The answer to the first question is yes. The answer to the second is more complicated.
“The smart-aleck answer is that I like to make up wheats that never existed before,” said Morris, who has developed both a waxy wheat and a super soft wheat. “The real answer is that I’ve spent a fair amount of my career working with the underlying genes related to kernel texture. By manipulating those genes, I can develop new or innovative classes of wheat with novel flour characteristics that can be used to make things we haven’t been able to make before.”
As Morris explains it, the fact durum isn’t ground into flour limits its culinary uses. “World durum production is not constrained by the plant, it is constrained by what we can do with the grain. But a soft durum can be used in many of the foods currently made using conventional flour,” he said. Although soft durum has a softer kernel, everything else about the durum is the same. It looks the Bread and butter? Or pasta and sauce?
same, it grows the same, it has the same disease resistance and susceptibility. It is only when you bite down on a kernel, that you realize something is different, Morris said.
“Everyone who has eaten products made from soft durum remarks on the flavor, using adjectives like nutty. It kills as a pizza crust,” he said, noting that its yellowish color in end-use products is another attraction.
Although durum is included as one of the six classes of wheat grown in the U.S., it’s actually a different species. Hard red winter, hard red spring, soft white, soft red and hard white are all what are called hexaploid. They have 42 chromosomes located on AA BB and DD genomes of the plant. Durum, a tetraploid, is a more primitive relative having 28 chromosomes located on the AA BB genomes. It lacks the DD genome, something hexaploid wheat borrowed in a cross with jointed goatgrass.
Morris compares durum and the traditional wheat classes to the difference between a chimpanzee and a gorilla or a horse and zebra. They’re highly related, but as different species, they can’t interbreed. That has made durum’s conversion from a very hard kernel to a very soft one a 15-year process essentially aimed at fooling Mother Nature.
Leonard Joppa, an ARS scientist who worked at the Northern Crop Sciences Laboratory in Fargo, N.D., before he retired, began the initial research. Morris has been working the last 10 years to breed two associated genes that confer softness into durum, a process made more difficult because these genes exists on the DD genome that durum lacks.
Morris’ explanation of how the transfer of soft kernel texture was accomplished is a complicated collection of technical words. It would be helpful to have a cereal science degree to fully understand them. In simpler language, he was able to facilitate a romance between the DD genome of a soft wheat and the AA or BB genome of durum. Backcrossing multiple times restored order and regulation to the plant. Once the trait was stable, he crossed it into Svevo, a durum variety that is currently in production in the desert Southwest and Italy.
“It is ready for prime time right now, and there are several companies begging for a commercial license to grow soft durum, but until a patent is secured, ARS doesn’t enter into any licensing agreements,” Morris said, adding that the patent application has, for the time being, been languishing in the Patent and Trademark Office. He hopes for a response within the next year.
Although Morris has, in essence, created a better mousetrap, it is unlikely the world of semolina producers will be knocking down his door. In fact, they may not be particularly happy. Millions of dollars of infrastructure needed to mill durum is already in place, and despite the advantages in both lower energy consumption and more culinary choices, “you don’t just chuck all that equipment in the landfill without thoughtful consideration.”
Dan McKay, owner of McKay Seed, a company which contracts for small amounts of conventional durum wheat in Washington, said soft durum would require a market development push akin to the efforts that have gone into bringing the hard white wheat class to market— with varying degrees of success. On the other hand, he said there are clear advantages to having a soft durum available, not the least of which is it could be milled in existing soft white mills in the region.
Morris said soft durum could complement the classes of wheat already being grown in Eastern Washington. And in certain situations, it may do better than existing alternatives.
“As a crop with a much longer evolutionary history, durum is actually richer in terms of disease resistance. And it has greater resistance to drought and heat, outyielding hexaploids in those circumstances by 10 to 15 percent,” he said.
As for overseas markets, which are the bread and butter of Northwest wheat producers, Morris said a soft durum could provide customers an expanded product portfolio without the need to build durum-specific semolina mills. Having many of the same properties as soft wheat flour, Morris said soft durum would significantly expand the range of possible consumer foods.