Canola oil extractions

Extruders. Extruders, or expanders, are widely applied in the oilseed industry, but mostly for press-cake conditioning in canola oil extraction, and for extruding soybean flakes into expanded collets for improved extraction yield. Extruders as cookers are used in some soybean extraction plants to achieve enzyme inactivation. Lusas investigated inactivation of enzymes during extrusion of soybean (69). Extruders could be used to pretreat canola seed to assist prepressing and to inactivate the enzymes however, commercial application of this process in canola industry is not known. 

One of the first studies examining the oxidative stability of canola oil extracted with SC-CO2 was conducted by Przybylski et al. (1998). Flaked canola seeds were extracted with SC-CO2 at 40°C and 41.4 MPa and the oil collected as fractions dependent upon the volume of CO2 used. Fraction 1 used 400 L of CO2, fraction II was the oil collected from 400 to 1600 L, fraction III was the oil collected from 1600 to 2800 L, and fraction IV was the oil collected from 2800 to 4800 L CO2. Collected fractions comprised 20%, 58%, 15% and 7% of the total oil extracted from flaked seeds. 

Mak, S.A. 2006. Sensory and Chemical Characterization of Canola Oil Extracted by Supercritical Carbon Dioxide, University of Alberta. 

Przybylski, R., Lee, Y-C. and Kim, I-H. 1998. Oxidative stability of canola oils extracted with supercritical carbon dioxide, LWT—Food Sci. Technol. 31 687-693. 

Soybean meal is the most frequently used source of supplemental protein in the United States (5). Cottonseed meal is another important protein supplement. Both meals are by-products from oil extraction of the seeds. Canola meal is derived from rapeseed low in emcic acid [112-86-7] and glucosinolates. Linseed (derived from flax seed), peanut, sunflower, safflower, sesame, coconut, and palm kernel meals are other sources of supplemental protein that are by-products of oil extraction (4). 

Flow rate and extraction time. Dynamic techniques for the extraction of carotenoids with SC-CO2 use flow rates that vary from 0.5 to 15 mL/min (measured at extraction temperature and pressure) with different effects depending on the matrix (Rozzi and others 2002 Subra and others 1998 Saldana and others 2006). Subra and others (1998) extracted (3-carotene from 1 to 2.5 g freeze-dried carrots and studied the effect of flow rates (0.4 and 1.2 liter/min) they obtained higher yields of (3-carotene at a flow rate of 1.2 liter/min. Sun and Temelli (2006) also evaluated the effect of flow rate (0.5 and 1.0 liter/min) on the extraction of (3-carotene with SC-CO2 + canola oil. The total carotenoids yield increased with flow rate, ranging from 934.8 to 1,973.6 pg/g dry carrot at C02 flow rates from 0.5 to 2 liter/min (measured at STP), respectively (Sun and Temelli, 2006). However, the lycopene yield decreased from 38.8% to 8% as flow rate was increased from 2.5 to 15 mL/min (measured at extraction temperature and pressure) (Rozzi and others 2002). 

Use of cosolvent. Various cosolvents, such as acetone, ethanol, methanol, hexane, dichloromethane, and water, have been used for the removal of carotenoids using SC-CO2 extraction (Ollanketo and others 2001). All these cosolvents except water (only 2% of recovery) increased the carotenoid recovery. The use of vegetable oils such as hazelnut and canola oil as a cosolvent for the recovery of carotenoids from carrots and tomatoes have been reported (Sun and Temelli, 2006 Shi, 2001 Vasapollo and others 2004). For the extraction without cosolvent addition, the lycopene yield was below 10% for 2- to 5-hr extraction time, whereas in the presence of hazelnut oil, the lycopene yield increased to about 20% and 30% in 5 and 8 hr, respectively. The advantages of using vegetable oils as cosolvents are the higher extraction yield the elimination of organic solvent addition, which needs to be removed later and the enrichment of the oil with carotenoids that can be potentially used in a variety of product applications. 

Sun M and Temelli F. 2006. Supercritical carbon dioxide extraction of carotenoids from carrot using canola oil as a continuous co-solvent. J Supercrit Fluids 37(3) 397-408. 

Wanasundara, U.N. and Shahidi, F. 1994a. Canola extract as an alternative natural antioxidant for canola oil. J. Am. Oil Chem. Soc. 71 817-822. 

Lipases have also been used in hyphenated extraction-reaction routes to deriving natural oils using two high-pressure units in series. Canola oil was extracted from canola flakes and fatty acid ethyl esters synthesised using an immobilised enzyme (Lipozyme M) (Kondo et al, 2002). It was clear that each unit in this process, whether reaction or extraction, needed to be run under its own optimum conditions. 

Kondo, M., K. Rezaei, F. Temelli and M. Goto, On-Line Extraction-Reaction of Canola Oil with Ethanol by Immobilized Lipase in Supercritical Carbon Dioxide, Industrial Engineering Chemistry Research, 41, 5770-5774 (2002). 

Canola Oil occurs as a light yellow oil. It is typically obtained by a combination of mechanical expression followed by n-hexane extraction, from the seed of the plant Brassica juncea, Brassica napus, or Brassica rapa (Fam. Cruciferae). The plant varieties are those producing oil-bearing seeds with a low erucic acid (C22 i) content. It is a mixture of triglycerides composed of both saturated and unsaturated fatty acids. It is refined, bleached, and deodorized to substantially remove free fatty acids phospholipids color odor and flavor components and miscellaneous, other non-oil materials. It can be hydrogenated to reduce the level of unsaturated fatty acids for functional purposes in foods. It is a liquid at 0° and above. 

In the sediment from industrial winterization, additional minor fatty acids and alcohols with 26 to 32 carbon atoms in the chain have been found in waxes and triacylglycerols (15). Most of these compounds are extracted from the seed coat and can initiate sediment formation in canola oil (16). 

The type and content of chlorophylls and their derivatives in the seed define the quality of extracted and processed canola oil, which has an impact on the quality of the processed oil. Composition and content of these pigments is related to the maturity of the seed (Table 10). 

The values for the crude oil compare closely with those of other commercial oils, such as soybean oil, when produced according to good extraction practices. Chlorophylls and sulfur compounds levels are higher in canola oil compared with most other commodity oils. The deodorized oil data reflect good refining practice and are similar to the data obtained with other deodorized commodity oils processed for food applications. 

Processing methods developed over the years are designed to extract canola oil from the seeds to produce a high-quality raw oil for further processing and a high-quality protein meal as an animal feed. 

Sunflower oil, as well as canola oil, is produced annually for sale of the oil primarily, unlike the case of soybean oil, mainly related to the demand for its meal. Sunflower oil accounts for 80% of the seed price, being six to seven times higher than the price of meal pellets. The price of sunflower seed is determined by the price of the extracted oil. 

Canola oil is obtained by mechanical expression or -hexane extraction from the seeds of Brassica napus (Brassica campes-tris) var. oleifera and certain other species of Brassica (Cruciferae). The crude oil thus obtained is refined, bleached, and deodorized to substantially remove free fatty acids, phospholipids, color, odor and flavor components, and miscellaneous nonoil materials. 

Canola oil has the lowest level of saturated fat compared to all other oils on the market at present. It has both a high protein (28%) and a high oil content (40%). When the oil is extracted. 

Canola oil contains mostly a- and y-tocopherol, with the amount of the latter twofold higher. The content of tocopherols in refined, bleached and deodorized (RBD) oils is reduced by processing, mainly by extraction, refining and deodor-ization. The lowest content of tocopherols was found in cold pressed canola oil. However, when the temperature of pressing was increased, the amount of... 

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