Agriculture, Growing and Processing Canola
Q. What is Canola?
A. Canola's history goes back to the rapeseed plant, but canola and rapeseed are not the same. Canola and rapeseed have different chemical compositions, therefore the names cannot be used interchangeably. In 1970's, Canadian plant breeders produced canola through traditional plant breeding techniques. The major differences are reduced levels of both glucosinolates (which contribute to the sharp taste in mustard and rapeseed) and licosenic and erucic acids (two fatty acids not essential for human growth) in Canola. "Canola" then, refers worldwide to varieties with two percent or less erucic acid in the oil and 30 micromoles per gram or less of the normally measured glucosinolates in the meal. Canada's canola services major markets and is internationally recognized as the industry forerunner in terms of quality. In Canada, rapeseed is now only grown under special contract and is used for industrial purposes.
Q. What does Canola look like?
A. Each canola plant grows anywhere from two thirds of a meter (two feet) to two meters (six feet) tall and produces groups of yellow flowers which in turn, produce seed pods about five centimeters (2 inches) long. Each pod turns brown as it ripens and contains twenty or more tiny round black or brownish-yellow seeds. Each seed contains at least 40 percent oil and so canola is classed as an oilseed.
Canola is a cool-season crop and grows particularly well on the prairies where cool night temperatures allow it to recover from hot days and limited amounts of rainfall. Growing and harvesting canola requires the same machinery used in growing cereal crops (wheat, oats and barley). This allows farmers to switch to canola production without a large cash expenditure.
Q. How is Canola produced?
A. There are two main types of canola grown, the short growing season Polish type (Brassica rapa, a brown/yellow seed) and the longer season Argentine type (Brassica napus, a black seed). Fields are cultivated, seeded, fertilized, and herbicides/pesticides may be applied to control insects, weeds and diseases.
Growing canola requires careful management on the part of the farmer as the crop has to be closely monitored in order to make sure it doesn't become diseased. Seedlings emerge four to ten days after planting. From a taproot, bottom leaves form a rosette, which send up a flower stalk as the plant grows. The flowering stage lasts 14 to 21 days and prairie fields at this time are a sea of brilliant yellow flowers. The flowers of the Polish type canola are fertilized by the wind and the Argentine type is self-fertilized. Bees, visiting the flowers for nectar pollinate the flowers by carrying pollen. Once the flowers are fertilized, pods for which take 35 to 45 days to fill. The field is swathed when about one half of the seed pods have turned color from green to yellow or brown. The swathed crop dries for approximately ten days and is combined.
Q. What challenges does Canola present to the farmer?
A. Canola seed is very fine (about the size of a radish or turnip seed) and it must be planted shallow in a moist seed bed so the seed can germinate. Since canola is subject to attack by several diseases and insects, canola is grown only one year in four on the same field. Seed treatment is used to reduce seedling disease and early flea beetle attacks. Herbicides are used to control weed growth. All chemicals used are registered with the federal government and assessed by the provincial government regarding application. The registration process is rigorous, takes years of approval and involves Health and Welfare Canada, Agriculture Canada, Environment Canada, Fisheries and Oceans Canada as well as the chemical company. Plant breeders continue to work to produce varieties, which have resistance to major diseases.
Q. Where does Canola go when it leaves the farm?
A. Approximately 45 percent of canola production is trucked to the nearest processor where it is crushed for oil. Plants are located across Manitoba, Saskatchewan and Alberta. Seed delivered to a processing plant is graded according to a strict grading standard established and maintained by the Canadian Grain Commission. Payment to the farmer is based on grade; Canada No. 1 Canola to a sample grade. Graded seed is then cleaned to remove plant stalks, grain seeds and other materials. Processing canola involves heating and crushing the seeds to release the oil. Once the oil is extracted, it is mixed and processed according to end product requirements. Different treatments are used to process salad oils, margarines and shortenings. The leftover meal is processed into pellets or mash. The United States is our largest importer of canola oil and meal. Approximately 40 percent of Canada's canola seed is directly exported to Japan for processing by Japanese crushers. Some canola seed is exported to Mexico and Europe. Canola meal is exported to Indonesia, South Korea and Pacific Rim countries.
Q. Who uses Canola oil and Canola products?
A. Canola oil is recognized for its nutritional qualities. It contains the lowest level of saturated fat of any fat or oil on the market. It is high in both monounsaturated fat (which may lower LDL cholesterol levels) and polyunsaturated fats, which are essential in human diets. Canadians are the largest per capita consumers of canola oil foodstuffs in the world. Canola is used in 80 percent of the salad oil market, 56 percent of the shortening market and 42 percent of the margarine market. Besides being used in cooking oil and sprays, salad dressings, margarines and shortenings, canola oil is also used in deep frying, baking, sandwich spreads, coffee whiteners and creamers. Consumer products containing canola carry the canola flower logo. Canola oil is also utilized in inedible products such as cosmetics, printing inks, suntan oils, oiled fabrics, plasticizers, plastic wraps, pesticides and industrial lubricants. Research is underway to discover other uses such as diesel fuel and industrial oils. Canola meal is used as fertilizer and as high protein feed for livestock, poultry and pets.
Q. Seeds per pod?
A. Argentine: 25 to 35 seeds per pod, with 80 to 100 pods per plant. Polish: 15 to 25 seeds per pod, with 60 to 80 pods per plant. Low sulfur levels reduce the number of flowers resulting in lower seed production.
Q. Can you remove wax stains with Canola Oil?
A. "Yankee's Home Hints." The directions say merely to "rub the spots generously with vegetable or canola oil and then gently wipe off any excess oil with a paper towel." I read in one source that this may be a "fight grease with grease" stain removal strategy. The chemical structure of wax is a long chain hydrocarbon, therefore highly nonpolar. (as is canola oil) My best guess is that wax is a nonpolar substance, and the simple chemistry adage "like dissolves like" applies, so the nonpolar canola oil dissolves the wax and removing the stain.
Q. How is Canola Oil Extracted?
A. The first stage in processing canola is to roll or flake the seed. This ruptures cells and makes the oil easier to extract. Next the flaked or rolled seeds are cooked and subjected to a mild pressing process which removes some of the oil and compresses the seeds into large chunks called "cake fragments". The oil collected through this mechanical stage is marketed as expeller or first press oil. The oil extracted during each step is combined. The oil is then subjected to processing according to end product use. Different treatments are used to process salad oils, margarine and shortenings.
Q. What is "solvent free" canola oil? What are its advantages and disadvantages, including health and cost aspects?
A. "Solvent free" canola oil is also known as Expeller, first press, or pure press oil. The solvent called hexane is not used during the extraction process.
Q. What is cold pressed oil?
A. The difference between cold pressing and hexane extraction of oilseeds lies in the initial extraction of the oil from the seed. Cold pressing is a traditional method in which the seeds are not heated before, during, or after the pressing process. Seeds are selected, cleaned, and crushed; they are then mechanically pressed at a slow pace to limit friction and avoid elevating temperatures above 60°C. Its color, taste, and odor are much more pronounced than those of refined oils.
Cold pressed oils, labeled as such and usually sold in health-food stores are comparable to whole-wheat flour, which has undergone very little processing and very little nutritive losses. Solvent-free oil is not however, as expensive as cold pressed oil. There is a higher antioxidant content to cold pressed oils (Vitamin E), which inhibits the absorption of cholesterol, and a significantly lower content of trans fatty acids. Despite these definite benefits, no regulation protects the Canadian consumer against oils falsely labeled "cold pressed". Overall, it is only a perceived difference that cold pressed oil is a better, healthier product.
The price of cold pressed oil tends to be slightly higher because of the lower recovery of oil.
Q. Is canola hot pressed or cold pressed?
A. First press, expeller press, and pure press oils are all controlled between 38°C and 60°C. For regular processing, the temperature range is 72-84°C.
Some Common Definitions
Cold Pressing: Cold pressed canola oil represents a much smaller volume and is generally marketed in specialty food stores. The production of cold pressed canola oil involves essentially the same steps as described during mechanical extraction. In addition, the temperature of cake during mechanical processing is controlled at 60°C or less by water cooling the screw press. Oil recovery when using cold-pressing techniques most often ranges from 75% to 85%. The price of cold pressed canola oil tends to be slightly higher because of the lower recovery of oil. Cold pressed canola oil is generally sold in bottled form directly to consumers and is usually not used in further food processing.
Preconditioning: The first step in canola processing where the seed is subjected to a mild heat and moisture treatment. This treatment improves the subsequent oil extraction.
Crude Oil: Oil that is produced during the extraction process. It contains various compounds that must be removed to improve stability and shellfire.
Hydrogenation: is a special process used in the production of margarine, shortening and other specialized products. Large quantities of oil are heated in a vacuum; once the proper temperature is reached, hydrogen is forced under pressure into the oil. The mixture is whipped until the desired amount of hydrogen is incorporated into the fatty acids. Hydrogenation is a process that changes the melting behavior of liquid oils and improves stability. It permits the use of higher cooking temperatures. This addition of hydrogen to the fatty acid makes it a hydrogenated fatty acid.
When oils are hydrogenated, their unsaturated fatty acids lose their natural form, called cis, and assume a new form called trans. This chemical form called trans changes the entire behavior of the unsaturated fatty acids. Instead of acting normally, they act much like saturated fats: they increase the LDL (bad cholesterol) and decrease the HDL (good cholesterol), and increase the risk of heart disease.
Canola Meal: is the solid portion of the canola seed remaining after the oil is removed. It is used as a protein ingredient in feed rations for poultry, swine, cattle, and fish.
Interesterification: is a process that makes canola oil more solid. It involves mixing canola oil with other edible oils that are more solid (saturated) by nature. (i.e. palm kernel oil) The result is a semi-solid product without hydrogenation.
Winterization: the process that oil undergoes in a plant setting to prevent it from going cloudy if stored in temperatures under 5°C in a warehouse environment.
Deodorization: is the final step in the refining of all vegetable oils, including canola. Deodorization involves the use of steam distillation, which removes any residual compounds, which could impart adverse odors and tastes. The oil produced is referred to as "refined oil" and is ready to be packaged and sent to consumers.
Bleaching: is a process where the oil is moved through natural, diatomaceous clay, which removes color compounds and other byproducts.