Low-linolenic

Tocopherols consist of a, (3, y, and 8 isomers and are effective antioxidants. Oomah et al. (1997a) observed that y-tocopherol (9.04 mg/100 g seed) was the predominant isomer of Canadian flaxseed cultivars. Total tocopherol ( r = 0.42) and y-tocopherol (r = 0.41) values were correlated with seed oil content. Kamm et al. (2001) reported the distribution of tocopherols and tocotrienols in high and low linolenic flaxseed. Results were similar to the findings of Oomah et al. (1997a) in which y-tocopherol content was greater (430-575 mg/kg oil) in high ALA flaxseeds, whereas low linolenic flaxseed exhibited lower (170 mg/kg oil) values. Bozan and Temelli (2002) compared tocopherol levels in oil extracted by supercritical C02 fluid and soxhlet (Table XI). Soxhlet-extracted oil had greater tocopherol levels (76.4 mg/100 g oil). These authors speculated that the temperature-pressure combination may have influenced the tocopherol extraction by supercritical C02 fluid. 

Batterham, E.S., Andersen, L.M., Baigent, D.R. and Green, A.G. (1991) Evaluation of meals from Linola(R) low-linolenic acid linseed and conventional linseed as protein sources for growing pigs. Animal Feed Science and Technology 35,181-190. 

Low Linolenic Acid Flaxseed Oil (Unhydrogenated) Low Linolenic Acid Linseed Oil... 

Identification Low linolenic flaxseed oil exhibits the following composition profile of fatty acids as determined under Fatty Acid Composition, Appendix VII. 

Low Erucic Acid Rapeseed Oil, 8 Low Linolenic Acid Flaxseed Oil (Unhydrogenated), 58 Low Linolenic Acid Linseed Oil, 58 Lysozyme, 18... 

Seedfats are characterized by low contents of saturated fatty acids. They contain palmitic, oleic, linoleic, and linolenic acids. Sometimes unusual fatty acids may be present, such as erucic acid in rapeseed oil. Recent developments in plant breeding have made it possible to change the fatty acid composition of seed oils dramatically. Rapeseed oil in which the erucic acid has been replaced by oleic acid is known as canola oil. Low linolenic acid soybean oil can be obtained, as... 

A second approach, when a diverse gene pool is available, is to interbreed species with appropriate traits by standard seed-breeding processes. This has been done very effectively with species of brassica to yield the modem oilseed rape (canola). If necessary, the gene pool can be extended by mutation resulting from chemical treatment or from irradiation. This may produce novel varieties with interesting traits and is the basis of the low-linolenic lines from linseed, and other examples are described in Section 9.3. 

Abbreviations LLCO—Low linolenic canola oil HOCO—High oleic canola oil ... 

Abbreviations HEAR—High erucic rapeseed oil CAN—Canola oil LLCAN—Low linolenic canola oil HOCAN—High oleic canola oil HOLLCAN—High oleic low linolenic canola oil SOY—Soybean oil SUN—Sunflower oil. 

High oleic acid canola oil is another development pursued in Canada, the United States, Sweden, Australia, and elsewhere (137). As with low linolenic acid canola oil, the aim was to produce stable frying oil, which will not need hydrogenation and thus avoid fraui-isomers formation. The oleic acid content in oil from seed developed in Canada is at about 78%, whereas linoleic and linoleic acids are lowered to approximately 8% and 3% respectively (see Table 2). Saturated fatty acid content is unchanged from the standard canola oil. There is limited commercial seed production for export to Japan. Also, there is increasing acceptance of the oil in Canada and the United States. The frying performance in tests was found to be similar to... 

There is considerable research and development work underway in many countries to test low-linolenic, high-oleic and high-palmitic canola oil varieties as base stocks to determine which of these oils with modified fatty acid compositions is best suited for the various products and applications. 

Canada is one of the major flaxseed producers and exporters, where a minimal amount of seeds is crushed to produce flax oil. Flax oil is mainly considered as a health food product but not a commodity oil. Figure 2 shows yearly production of flaxseeds in Canada for the past ten years. On average, Canada is producing above 800,000 MT (metric tons) of flaxseed per year (5). Part of this production is low linolenic acid varieties, which contribute from 10% to 15% to the total production. 

Figure 2. Flaxseed production in Canada. Data include low linolenic flaxseed. Source Canada Grains Council Statistical Handbook 2001 (5).

Some physicochemical properties of conventional flaxseed oil and low linolenic varieties are presented in Table 1. The higher specific gravity of 0.935 observed for flaxseed oil than other vegetable oils can be directly attributed to the high contribution of linolenic acid. It is in line with the specific density of fatty acids that increases from 0.895 to 0.9038 and to 0.914 for oleic, linoleic, and linolenic acids, respectively (7). 

Fatty acid composition of regular flax oil is different from other commercial oils because of the very high contribution of ALA, usually above 50% (Table 2). Because of the high content of this unique fatty acid, flaxseed and flax oil are often used as food supplements, where enrichment with omega-3 fatty acids is needed. This fatty acid is susceptible to oxidation it oxidizes 20 0 times faster than oleic acid and 2 times faster than linoleic acid (8). This property makes the oil a good material for paint and plastic production where fast oxidation is required. Flax oil contains low amounts of saturated fatty acids (SFA) compared with low linolenic flax oil (Linola), soybean, and sunflower oils however, it is higher than canola oil (Table 2). Canola oil contains the lowest amount of SFA among all commercial oils. 

Fatty Acid Composition The fatty acid content of RBO is mainly palmitic, oleic, and linoleic acid (Table 24). The low linolenic acid content of RBO makes it stable to oxidation. Several studies reported variations in fatty acid composition of RBO (90, 95-96). Goffman et al. (90) studied the fatty acid composition of 204 rice varieties. Genotype and environment significantly affected stearic, oleic, linoleic, and linolenic acids but not palmitic acid content of the RBO. The ratio of saturated to unsaturated acid ratio (S/U) was correlated to the palmitic acid content of the oil. Japonica lines had low palmitic acid content and S/U ratio, whereas Indica lines were characterized by high palmitic acid content and high S/U ratio (90). 

Predominate use of a particular oil in a given region of the world is dependant on world trade movement. For many years, cottonseed oil was the main source of cooking and salad oils in the United States. However, since World War II, soybean oil has become the most prominent oil. Other oils, particularly those with high oleic content or low linolenic content, are becoming more important, as they do not require hydrogenation for stability (14, 15). Typical compositions of some commercially important cooking and salad oils are shown in Table 1. 

A study on the effect of heating on the oxidation of low linolenic acid canola oil at frying temperatures under nitrogen and air clearly showed that a significantly lower development of oxidation was evident for the low linolenic acid canola oil. Reduction in the linolenic acid content of canola oil reduced the development of room odor at frying temperatures. 

Anderson GJ, Connor WE. Accretion of n-3 fatty acids in the brain and retina of chicks fed a low-linolenic acid diet supplemented with docosahexaenoic acid. Am J Clin Nutr 1994 59 1338-1346. 

Figure 2.3 Oxidation and tocopherol retention during modified (A) and conventional (B) refining of various types of soybean oils. Key —0—, high-oleic acid soybean oil (HO) — —, low-linolenic acid soybean oil (LLL) —A—, lipoxygenase-free soybean oil (LOX) —K—, low-saturated fatty acid soybean oil (LS) — —, commodity soybean oil (CS). Source Wang and Johnson 2001b.

Miller, L.A. and White, P.J. (1988) High temperature stabilities of low-linolenate, high-stearate and common soybean oils. J. Am. Oil Chem. Soc., 65, 1324—1326. 

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