Soy: healthy and functional

Soybeans are a member of the legume family that are known to contain high amounts of good quality protein as well as oil. Traditionally in North America, the soybeans were crushed to extract the oil, which was then used for commercial applications in frying or in the production of shortenings and margarines by the process of partial hydrogenation.

Partial hydrogenation resulted in the development of trans-fats. But this process was necessary because it provided two important solutions to the food industry. Partially hydrogenated oils are more stable, resisting rancidity, and can be designed to have variable melting points. However, trans-fats have been shown to be detrimental to human health, and so safe alternatives are now available.

The soy meal left after the extraction of oil was originally used as animal feed because of its high nutritional value in protein. Many ingredients are now produced from soybeans. These ingredients are extensively used in food products to provide functionality, replace more costly ingredients, and more recently to deliver health benefits. Such ingredients include soy flour (full-fat or defatted), soy grits, soy protein concentrates and isolates, lecithinated flour and lecithin, as well as soy fibre.

Using traditional soy ingredients in baked goods presented various challenges. They introduced a beany flavour in the finished product that was attributed to certain enzymes in the bean, and their functionality as replacement of other expensive ingredients was not as effective as it is now. New manufacturing processes have resulted in better functional ingredients which are now widely used.

Enzyme active soy flour is processed in a way to retain the activity of the lipoxygenase enzyme. It is mainly used in the production of white bread to improve the rheology of dough, whitening of crumb and improve texture. Its usage is restricted to very low levels since it will result in formation of volatiles that will give off-flavours in the bread. Heat-treated soy flour results in the deactivation of the inherent enzymes, thus reducing or eliminating the off-flavours in baked goods. The degree of heating (toasting) determines the protein dispersibility index (PDI) of the soy flour. The longer the flour is toasted the lower the dispersibility index and off-flavour levels.

The most widely used soy ingredient in the baking industry is the defatted soy flour. It is more economical and contains high amounts of protein (about 50 per cent) compared to wheat flour (nine to 12 per cent), providing an opportunity to increase protein content. Soy flour provides functionality such as texture improvement, dough conditioning, crumb and crust improvement, and reduction of fat absorption in fried goods such as doughnuts. Incorporation of soy flour increases the water absorption and may slow staling in breads. Soy ingredients may be used in baked goods to partially replace more expensive ingredients such as milk and egg powders. More effective ingredients have been developed containing soy protein concentrates (60 to 70 per cent protein) and isolates (over 90 per cent protein) to be used as replacement of egg and milk products. Other functional ingredients from soy include lecithinated flour and lecithin. Lecithin is a natural emulsifier and is known to improve dough handling, bread volume, crumb structure and tenderness.  

On the health front, soybeans have been recognized as having a great potential to improve health due to their good quality protein content, the presence of isoflavons, micronutrients and fibre. Many credible scientific studies have indicated there are many health benefits to consuming soy.

Scientific evidence resulted in the permission of a health claim in the U.S. for products that contain a specified amount of soy protein a few years ago. Last year, progress was made in Canada as well. The Health Canada position is outlined in a document posted on their website in March 2015 entitled “Summary of Health Canada’s Assessment of a Health Claim about Soy Protein and Cholesterol Lowering.” Health Canada reviewed the scientific evidence available that supported the proposed claim, which includes “foods or food ingredients that contain proteins derived from the soybean (Glycine max(L.) Merr. Fabaceae). Foods and ingredients eligible for the claim include soy beverages, tofu, miso, tempeh, natto, soy cheese, soy nuts, isolated soy protein (ISP), soy protein concentrate (SPC), textured soy protein (TSP) and soy flour.” Ingredients such as isolated soy protein, soy protein concentrate and soy flour would be candidates for baked goods desiring such a claim. The document states: “Health Canada’s Food Directorate has concluded that scientific evidence exists to support a claim about soy protein and blood cholesterol lowering.” In attempting to make the above therapeutic claim permitted by Health Canada, it is recommended to consult Health Canada or their website for more details on the primary statement, additional statements as well the daily amount for the claim that can be used for your product.

Soy ingredients represent opportunities for the baking industry. However, we should take into consideration that soy is one of the 10 priority food allergens and its introduction in the food manufacturing environment presents additional challenges.

For more information, or fee for service help with food technical and processing issues and needs please contact Dr. John Michaelides at John Michaelides Consulting at 519.743.8956 or at Bioenterprise at 519.821.2960,
by e-mail: j.jmichaelides@gmail.com. Bioenterprise is a company of experienced professionals that coach and mentor emerging agri-technology companies from planning to start-up to profitability and beyond.