REVIEW Minor Components in Canola Oil and Effects of Refining on These Constituents: A Review Saeed Mirzaee Ghazani • Alejandro G. Marangoni Received: 23 May 2012 / Revised: 18 December 2012 / Accepted: 12 April 2013 / Published online: 24 April 2013 Ó AOCS 2013 Abstract Crude canola oil is composed mainly of tria- cylglycerols but contains considerable amounts of desir- able and undesirable minor components. Crude canola oil is refined in order to remove undesirable minor compounds that make this oil unusable in food products. However, refining can also cause the removal of desirable health- promoting minor components from the oil. The first section of this review describes the chemical composition of canola oil, followed by a brief introduction to the effects of minor components on canola oil quality and stability. Following a review of traditional canola oil refining methods, the effects of individual refining stages on the removal of both desirable and undesirable components from canola oil are presented and contrasted with other common vegetable oils. Keywords Canola oil Á Refining Á Minor constituents Á Phytosterols Á Tocopherols Á Polyphenols Á Degumming Á Neutralization Á Bleaching Á Deodorization Introduction Vegetable oils and fats are the raw materials in the man- ufacture of shortenings, margarines, frying oils, and other edible products used by both the food manufacturer and the household. Vegetable oils can also be used to formulate specialty lipids such as human milk fat substitutes for infant formula, low calorie fats and oils and edible oils enriched in essential long chain omega-3 fatty acids and medium-chain fatty acids. They also have applications in the oleochemical, leather, paint, rubber, textile and phar- maceutical industries. Vegetable oils and fats are the most dense source of food energy, more than any other food group. Vegetable oils are also carriers of fat soluble vita- mins, and provide essential fatty acids. Crude vegetable oils and fats consist predominantly of triacylglycerols (TAG) along with other minor components such as free fatty acids (FFA), monoacylglycerols, dia- cylglycerols, phospholipids, free and esterified phytoster- ols, polyphenols, triterpene alcohols, tocopherols, tocotrienols, carotenes, chlorophylls, hydrocarbons (e.g. squalene), trace metal ions (e.g. iron, sulfur and copper), oxidation products, gums, waxes, pesticide residues and flavor compounds [1]. Canola oil was introduced in Canada in 1974. Since 2000, canola oil in Canada is extracted mainly from the seeds of genetically modified Brassica napus L. Some canola oil is still extracted from Brassica rapa L. The rapeseeds currently in use are bred specifically to be low in both erucic acid and glucosinolates ( \ 0.1 % erucic acid in the oil and \ 8.5 lM/g glucosinolates in the seed). The reduction of erucic acid in the rapeseed oil causes a dra- matic increase in the oleic acid content of canola oil. Different types of modified canola seeds have been developed by plant breeders (high oleic, high stearic/lauric and low linolenic canola). High lauric and high stearic canola oils are currently not in commercial production but they have potential for use in confectionery coatings, cof- fee whiteners, whipped toppings, and baked products as a substitute for hydrogenated oils [2]. S. M. Ghazani Á A. G. Marangoni (&) Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada e-mail: amarango@uoguelph.ca 123 J Am Oil Chem Soc (2013) 90:923–932 DOI 10.1007/s11746-013-2254-8