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Eurostar, Brigade: new durum varieties, new markets?


November 30, 1999
By Andrea Hilderman

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Technician Rosa DeStefano prepares a dough patty for alveograph testing. photos courtesy of the Canadian International Grains Institute. Desert durum from the US has always held the high ground when it comes to gluten strength.

Desert durum from the US has always held the high ground when it comes to gluten strength. It possesses that elusive protein quality that gives pasta its world-renowned “al dente” texture, or bite. Now, Canadian breeders are bringing forward varieties that may open that market up for Canadian farmers. “Both of these sister varieties present the first opportunity for us to market an extra strong durum into Europe,” explains Lisa Nemeth, technical manager at the Canadian Wheat Board (CWB).

“Cadmium levels in other varieties we had before were too high, above the European tolerance of 0.2 milligrams per kilogram, or 0.2 ppm, that we couldn’t take the risk.” China and Japan also have adopted the same tolerance as Europe, which is based on Codex Alimentarius recommendations.

In the past, durum grown on the Prairies accumulated relatively high levels of the cadmium that is found in the soils. Cadmium is a naturally occurring heavy metal that is a known carcinogen and its level in food is regulated in most countries.

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These two new extra strong durum varieties, Eurostar and Brigade, were bred by Dr. John Clarke at the Agriculture and Agri-Food Canada research station at Swift Current, Saskatchewan, in the heart of durum country. For years, breeders have been working on reducing the cadmium uptake in Canadian durum varieties, with their success culminating in varieties like Strongfield, which has low cadmium but conventional strength. Finally, Eurostar and Brigade demonstrated low cadmium along with the extra gluten strength and will be available to farmers commercially in 2011 for the first time.

Launching a new type of cereal onto the market is a complex process. A team of experts joined forces to educate and learn from customers and prepare them for the introduction of these new durum varieties. Nemeth, from the CWB, Elaine Sopiwnyk, head of analytical services at the Canadian International Grains Institute (CIGI) and an expert from the Grain Research Laboratory at the Canadian Grain Commission travelled to end-use manufacturers in Italy and the US, and worked with the various quality teams to gain a better understanding of where and how extra strong durum fits into their process. “There are specific tests that are used to evaluate gluten strength: the alveograph, gluten index and various organoleptic evaluations,” says Nemeth. “It’s the latter that can confuse the picture. Every manufacturer (just like every brewer, for instance) has very specific sensory requirements of their end-product pasta, most notably the ‘bite’.” 

It is this combination of tests that makes it so difficult to get into the customer’s head and understand exactly what quality it is they need in a variety and why. Additionally, because Canadian durum is almost always used in blends, it is even more difficult to assess. “They know what they want, but we are not always sure how we’re meeting their needs,” says Nemeth. “That sometimes will take a few years of using the variety in their manufacturing plants.”

Farmers can grow identity preserved Eurostar and Brigade. Check out www.cwb.ca, or contact Alliance Seed Corporation or Viterra for more information on the program.

Breeding is a process that strives for continual improvement. Looking ahead, there will be more and improved durum varieties for farmers. In winter 2010, five of the seven durum varieties in their second year of evaluation were supported for quality, with two having extra strong gluten. Of the 11 first-year varieties evaluated, five were supported, all conventional types.

Unfortunately, the 2010 growing season took a toll on the durum testing locations, and nothing was suitable for further evaluation. This will set the process back a year.

The tests to measure gluten strength 

Alveograph
The alveograph is a rheological piece of equipment originally designed in France to test soft wheat. Now it is widely used to test the extensibility and elastic qualities of cereal doughs. The mixer of the alveograph generates a dough, which is then extruded, rolled to a consistent thickness, cut into patties, then put in a relaxation chamber to allow the dough to relax. 

Air is then blown into the patty to create a bubble. The first burst of air tells how much resistance the dough has to inflation. Then as more air goes in, the extensibility of the dough can be measured.

The reason this is important is perhaps easier to understand with bread where the bubbles that are formed by the dough get filled with gas from the yeast. Those bubbles are needed to grow a loaf of bread: if they burst, the bread will collapse.

Gluten index
Semolina is mixed with salt water in special mixing bowls with holes in the bottom. A dough is formed in the first few seconds and as more salt water is added, anything that is not gluten is rinsed out of the bowl.  What is left at the end of the test is a ball of gluten. This is then put in a special centrifuge cartridge that, when spun, will permit gluten to pass through the sieve of the cartridge. Then, the weight of the gluten that is put into the special centrifuge cartridge is weighed and compared to the weight of gluten that passes through the mesh. Samples with lots of extensibility and little resistance will have more gluten pass through than samples with lots of resistance to extension. 

Gluten index is measured on a continuum from 0 to 100. Conventional durum ranges from 30 to 70, extra strong durum from 70 to 95. 

 


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