Premium lentils are sold on quality, based on their having that red cotyledon and good milling efficiency.
A Saskatchewan farmer and researcher said milling efficiency is something that producers can control.
University of Saskatchewan research by agrologist Jesse Bruce of Moose Jaw, Sask., shows that the timing and method of harvest has a significant effect on final quality.
The football recovery is a critical factor in overall quality. It refers to a miller’s ability to easily dehull the lentil without splitting the seed.
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Plant breeder Bert Vandenberg said red and green lentils should be thought of as different crops. The green lentil is prized for its colour and having an intact seed coat.
For human consumption preparation begins with soaking or spouting.
Red lentils are used in soups and stews and are dehulled. The resulting splits or footballs, as whole dehulled lentils with intact cotyledons are known, can be prepared as quickly as milled rice.
Unlike green lentils, red lentils don’t meet quality standards in many importing markets when they are delivered at 14 percent moisture with a hard-to-remove hull. It is preferred at lower moisture levels of about 12.5 percent, when the hulls are more easily removed.
Western Canada’s foray into red cotyledon lentils began more than a decade ago with crimsons. They were not well received when importers discovered the Canadian crop was pretty to look at but hard to peel.
Canadian lentil growers dominated the international export market, but their experience was with the green varieties and keeping those seed coats on. Prices for Canadian crimsons were discounted, which left a bad taste in prairie producers’ mouths.
Vandenberg said about 80 percent of the world’s lentils have a red cotyledon and that 95 percent of those have their seed coat removed before they are sold to consumers.
Western Canada competes with four other growing areas around the globe for lentil markets. Each harvests its crop a few months after the other, meaning there is always competition for the seller.
In other exporting regions, the growing season is typically followed by hot, dry weather, resulting in high quality for red lentils. The crop has low moisture and harvests are longer, open seasons.
Canadian farmers face heavy morning dew in late summer and early fall rain. Harvest seasons are capped off by frosts and even early snowfall, not ideal for producing dry legume seeds.
Commercial millers are not economically efficient if their milling efficiency drops below 80 percent and Vandenberg said most of these companies are satisfied at 85.
A three year agronomy research project by Bruce and his colleagues at the U of S looked at CDC Robin, CDC Imperial CL, CDC Rosetown, CDC Blaze, CDC Impact, CDC Rouleau, CDC Redberry and CDC Red Rider.
Researchers tried a variety of approaches in handing the harvest. Early, mid- and late-season swathing and desiccation with diquat, Reglone.
Researchers used a Stake lab dehuller and a Turkish tabletop dehuller to test the results for efficiency and delivery of complete cotyledons, the footballs desired by millers.
Good, warm, dry, harvest conditions at three sites where the lentil trials took place in Saskatchewan delivered crops that showed no additional benefit from any particular timing of swathing or desiccation. Milling efficiency was in the 85 to 90 percent range. Smaller seeded varieties, such as Robin and Imperial CL tended to be less efficient.
Bruce said when tough moisture conditions plagued harvest, the effect of the different strategies played out.
Under cool, wet conditions, early desiccated crops saw milling efficiency drop to below 70 percent.
Early swathing produced crops that milled above 85 percent efficient. All other strategies for harvest produced less than satisfactory results and small-seeded varieties were still the least efficient to mill.
Dehulling tests produced the same results with early swathing delivering the best quality products.
When it came to recovering footballs, early swathing once again took the prize, although in this case variety was the most important.
The smaller-seeded varieties delivered the most footballs. However, some of the damage to larger varieties was caused by the fixed mill size, something large commercial mills could adjust for. Weather too was critical, said Bruce.
“We saw a significant drop off in footballs if there had been fall moisture cycles affecting the crop,” he said.
“Under ideal conditions the approach to harvest isn’t going to make a big difference,” he said.
“When weather conditions are less than ideal is when your harvest strategy will determine the quality of your crop,” he said.
Bruce also found that red cotyledon lentils with brown seed coats didn’t handle poor weather conditions as well as those with grey seed coats.
“Mostly you can manage your risk in tough conditions if you choose to swath early. You will have increased yield, higher percentage of milling recovery, football and dehulling efficiency,” he said.
Early desiccation will have the opposite effect if the conditions are poor.
He said desiccation produces higher milling values because maturity increases, and crop quality and yield improve when desiccants are applied at the recommended plant stage.
Early seeding is key to managing late season harvest risk, along with well-timed weed control, said Bruce.
