Potential multifunctional high-protein food ingredient from a plentiful source

Researchers at Burcon NutraScience Corp. of Vancouver (www.burcon.ca) have developed and patented a process for extracting high-quality plant protein from protein-rich canola meal (rapeseed meal) or any oilseed. Applied to canola meal, the technology yields Puratein, a 90-percent protein isolate that has excellent nutritional and functional characteristics. Food Engineering interviewed Burcon Vice-President of Engineering Larry D. Barker, P.Eng, to learn about the process and Puratein's potential as a food ingredient.

FE: What is Puratein? How would you define it?

Barker: Puratein is a protein isolate, 90-percent protein, extracted from canola meal. Canola is the rapeseed variety bred by Canadian agronomists mainly for its low level of saturated fat. Canola meal results from the removal of oil from the canola seed. The meal is abundant, inexpensive and currently sold as a feed ingredient for livestock.

FE: How is Puratein extracted from canola meal?

Barker: The process is relatively simple, consisting of five unit operations, although the protein chemistry which occurs is fairly complex. First, there's an extraction step where the meal is mixed with water and salt to solubilize the protein. That's followed by a clarification step to remove the solids; a purification and concentration step; and a protein-recovery step, where cold water is added to reduce the ionic strength of the solution and precipitate the protein. The protein forms microscopically large spheres called micelles. The micelles are recovered and spray-dried to form a free-flowing light-colored powder. This powder is Puratein, containing at least 90 percent protein with significant reduction of the anti-nutritional factors usually associated with canola meal.

FE: What are the advantages of the process as compared to conventional processes to extract, for example, soy proteins?

Barker: Current processes to extract proteins from sources such as soy and gelatin typically use extremes of acid and base. These chemicals reduce the nutritional value and functional properties of the protein, and pose environmental challenges. The Puratein process uses no harsh chemicals, and creates no noxious odors or wastes. Inputs, end products and byproducts are all biodegradable, making the process environmentally responsible.

FE: Can the same process be used to extract protein from other vegetable sources, such as soy?

Barker: Yes, it's patented for extracting protein isolates from oilseed meals, which include soy, flaxseed and other rapeseed varieties.

FE: What are the anti-nutritional factors in canola meal which are reduced by this process?

Barker: These are glucosinolates, phytates and phenolic compounds found in varying degrees in all plant materials. They all work in different ways, but are anti-nutritional because they tend to impede the body's uptake of nutrients such as vitamins and minerals. Canola meal, although it contains high-quality protein, has high levels of anti-nutritionals and high levels of fiber, which makes it less valuable than soybean meal as a feed ingredient. But the high level of protein in canola meal led our researchers to find a way to isolate the protein from those negative factors.

FE: What has to be done to commercialize the process?

Barker: There is a fair bit of work still to be done. The process was developed in a pilot plant with a liquid capacity of 400 litres of solubilized canola protein per batch. We're now scaling-up to a semi-works plant which will be completed in about three months and will run at a flow rate of about 400 kgs of meal per hour. For an economical commercial process, we would scale that up another 10 to 20 times.

FE: What must be done to achieve regulatory approval for human consumption?

Barker: We'll go through the approval procedure for GRAS status with the FDA. We are also undertaking a battery of toxicology and other studies to meet the regulatory requirements.

FE: What are the nutritional benefits of Puratein?

Barker: Canola protein is unique in that it is a "complete" protein. Nutritionally, it's similar to egg, meat or milk although from a vegetable source. The Protein Efficiency Ratio (PER) of canola concentrate is 3.29 as compared to 3.71 for egg white, 3.36 for minced beef and 3.13 for casein. Soy, on the other hand, has a PER of 1.60 -- half that of canola. Because canola belongs to a family of plants which includes broccoli and Brussels sprouts, it also contains an active phytochemical called isothiocyanate, a known anti-carcinogen whose activity is being researched.

FE: Why is Puratein classified as a protein isolate?

Barker: According to industry-accepted standards, a protein isolate must contain at least 90 percent protein by weight. Samples of Puratein produced in a pilot process and analyzed for protein content by independent laboratories using the internationally-recognized Kjeldahl method contained an average of 107.4 percent protein. This is statistically impossible, of course, but that's because the Kjeldahl conversion factor of 6.25 for multiplying nitrogen content was originally developed to characterize animal proteins. Academic literature indicates that plant proteins should have Kjeldahl conversion factors of 5.49 to 5.85, which means that the true protein content of canola protein isolate is at least 94.4 percent.

FE: What are the functionalities of Puratein as a food ingredient?

Barker: They are very similar to egg white, which is probably the most functional protein known but is sometimes restricted in application because of its price. We've identified 11 different functionalities that a protein can have, and Puratein is the only one which seems to have all of them. It has foaming, whipping, gel-forming and emulsification properties, and binds water and fats. It's fat content is less than 0.10 percent, so it reduces rancidity and improves stability.

FE: What are Puratein's potential ingredient applications?

Barker: Protein is an essential nutrient, so potential applications cover a broad range. Examples might include a protein supplement in beverages; an egg-white replacer in baked goods; a replacement for dairy or soy proteins in, for example, veggie burgers; and as a replacement for animal proteins in foods for consumers who prefer to avoid them.

FE: What are its sensory characteristics?

Barker: Unlike some soy proteins which have a "beany" flavor, Puratein has a bland taste and imparts no flavor when incorporated into foods.

FE: When ready for commercial production, will Burcon manufacture Puratein or license the technology to others?

Barker: We're investigating strategic alliances with two types of potential partners: multinational agribusiness companies for manufacturing and distribution, and "pharma/nutrition" companies which might use Puratein as an ingredient in nutritional supplements, infant formulas and nutraceutical products. We're working right now toward developing alliances with branded-products companies to create a demand for the product when we're ready to manufacture it. At that point, because of the worldwide potential of this product, it's likely we would either license the technology or enter some sort of joint-venture arrangement for production and distribution. It's important for us, however, to start developing demand now, because that's of value to whatever companies we work with to manufacture and distribute the product.