Linoleic acid vegetable oils

Animal Fat SATURATED FATTY ACIDS OLEIC ACID LINOLEIC ACID SATURATED FATTY ACIDS Vegetable Oil OLEIC ACID LINOLEIC ACID... 

Rats fed a purified nonlipid diet containing vitamins A and D exhibit a reduced growth rate and reproductive deficiency which may be cured by the addition of linoleic, a-linolenic, and arachidonic acids to the diet. These fatty acids are found in high concentrations in vegetable oils (Table 14-2) and in small amounts in animal carcasses. These essential fatty acids are required for prostaglandin, thromboxane, leukotriene, and lipoxin formation (see below), and they also have various other functions which are less well defined. Essential fatty acids are found in the stmctural lipids of the cell, often in the 2 position of phospholipids, and are concerned with the structural integrity of the mitochondrial membrane. 

RP-HPLC with nonaqueous solvents and UVD at 246 nm was developed for the determination of low level POVs of vegetable oils. These measurements are specific for conjugated diene peroxides derived from vegetable oils with relatively high linoleic acid content. These measurements may be supplemented by nonspecific UVD at 210 nm and ELSD for detection of all eluted species. The elution sequence of the triglycerides in a nonaqueous RP-HPLC is linearly dependent on the partition number of each species, Vp, which is defined as = Nq — 2Ni, where Nq is the carbon number and is the double bond number. In the case of hydroperoxides = Nq — 2Nd — Vhpo, where Vhpo is the number of hydroperoxyl groups in the molecule (usually 1 for incipient POV). For... 

Dietary intake is of great importance. Linoleic acid (C18 2o)6) and a-linolenic acid (C18 3o)3) are the parent essential fatty acids for humans. Both fatty acids derive from vegetable oils. Higher fatty acids are then produced by chain elongation and desaturation. In addition, some of the prime essential fatty acids, AA (C20 4o)6), EPA (C20 5w3) and DHA (C22 6w3), can be obtained directly from the diet. Meat and eggs are rich in AA, whereas fish is a rich source of EPA and DHA [14]. 

The major properties of nine of the principal edible vegetable oils are summarized in Tbble 2. For descriptions of the constituent acids, see also Arachidic Acid Capric Acid Caproic Acid Lauric Acid Linoleic Acid Linolenic Acid Myristic Acid Oleic Acid Palmitic Acid and Stearic Acid and Stearates. 

In some commercial samples of these vegetable oils, there appeared to be some isomerized linoleic acid, and additional small peaks containing these components eluted in front of the corresponding main peaks on silver ion chromatography. 

The presence of vegetable oils of high linoleic acid content in olive oil can be detected by measuring its authenticity factor (Au) as follows ... 

Figure 14.1. Reaction mechanism for the selective hydrogenation of vegetable oils (here, linoleic acid).

Reaction temperature and time were significant operating parameters, which are closely related to the energy costs, of the biodiesel production process. Figure 7 shows the effect of reaction time on the transesterification of rapeseed oil at a catalyst concentration of 1%, molar ratio of 1 6, and 60°C. Within 5 min, the reaction was rapid. Rapeseed oil was converted to above 85% within 5 min and reached equilibrium state after about 10 min. Several researchers reported that the conversion of vegetable oils to FAME was achieved above 80% within 5 min with a sufficient molar ratio (8,11). For a reaction time of 60 min, linoleic acid methyl ester was produced at a low conversion rate, whereas oleic and linolenic methyl ester were rapidly produced. 

The vegetable oil used was rapeseed oil (Nacalai Tesque Kyoto, Japan) without further treatment. The fatty acid content of the rapeseed oil mainly consisted of unsaturated fatty acids (93 wt%), with the saturated fatty acids of palmitic and stearic acids accounting for only a small amount (7 wt%). Various fatty acids of oleic (C181), linoleic (C18 2), linolenic (C18 3), and palmitic (C16 0) acids as well as their methyl esters were purchased from Nacalai Tesque. Anhydrous methanol and distilled water were also supplied by the same company. 

Rapeseed oil and its fatty acids (stearic, palmitic, oleic, linoleic, and linolenic acids) were chosen as the samples of vegetable oil. The experiments were performed in the batch- and flow-type supercritical biomass conversion systems developed in our laboratory. For the batch-type system, a reaction vessel was made of Inconel-625 with a volume of 5 mL for the flow-type system, the supercritical treatment tube was constructed from Hastelloy stainless steel (HC 276) with length of 84 m and an id of 1.2 mm, with the total volume being about 95 mL. Detailed information about the equipment can be found elsewhere (13). 

Linoleic acid is the parent essential fatty acid of the oj-6 series, and as such, must be obtained in the diet.24 It is primarily derived from vegetables and nontropical vegetable oils. When linoleate was... 

Rapeseed methyl ester (RME) is another alternative biofuel that can be used in diesel engines. RME has the advantages that it is renewable compared to diesel, non-toxic and less flammable compared with many other fuels, like ethanol. RME has the same cetane number, viscosity and density as diesel, contains no aromatic compounds and is biologically degradable with minor contamination in soil. RME can be produced from vegetable oils, but is mostly produced from rapeseed oil by pressing of the seeds or by extraction. Up to 3 tons of rapeseed can be produced from one hectare. The fatty acids in rapeseed oil are mostly oleic acid, linoleic acid and linolenic acid. The oil is pressed from the plant and after some purification allowed to react with methanol in the presence of potassium hydroxide as a catalyst, to produce a methyl ester, see Figure 6.6. 

A remarkable feature of lipids, either vegetal or animal, is that they share the same fatty acids in triglycerides in the range C12-C20 (Table 14.3). However, there are significant differences in composition. Thus, soybean, sunflower and rapeseed oils are all based on C18 acids, the first two being richer in unsaturated linoleic acid, which could introduce a problem of stability with respect to oxidation. The palm oil has an important amount of C16 acid. Coconut oil is given as an example of Cl2-04 rich oil. As in palm oil the composition of tallow spreads over Cl6-08 acids. 

Extracted from the bean and often called Soyabean oil. A versatile carrier suitable for all skin types. It is comparatively high, up to 17%, in unsaturated fatty acids with the unsaturated linoleic (54%), oleic (24%), palmitic (10%), linolenic (7%) and stearic (4%). It also contains the highest amount of lecithin of any vegetable oil and the cold pressed oil is particularly high in vitamin E. It needs careful storage as it oxidizes easily. Soya oil may cause allergic reactions and has been reported to damage hair. 

The earliest efforts to modify the composition of milk fat used an insoluble formaldehyde-crosslinked protein to encapsulate unsaturated vegetable oils. In numerous studies using this approach, linoleic acid was increased to as high as 35%, w/w, of the total milk fatty acids (reviewed by McDonald and Scott, 1977). Bitman et al. (1973) fed increasing amounts of safflower oil encapsulated in formaldehyde-treated casein. The content of milk fat increased linearly from 3.5 to 4.6% as supplemental protected oil was increased from 0 to 1320 g/day per cow. The concentration of linoleic acid increased to 33% of total milk fatty acids, with a compensating decrease in Ci6 o and a smaller decrease in Ci4 0. The concentration of milk fat decreased to lower than pretreatment levels when the supplement was removed, a common observation (Pan et al., 1972). A typical milk fatty acid profile from cows fed a protected sunflower/soybean (70/30) supplement is shown in Table 2.1. 

About one-fourth of the TFAs in ruminant fat is represented by RA, which is by far the predominant natural isomer of conjugated linoleic acid (CLA). The remaining TFAs are mainly trans monounsaturated acids of which vaccenic acid (VA /ra/iv-11-Cisi) is predominant. On the other hand, hydrogenated vegetable oils contain predominantly elaidic acid (trans-9-Ci8 i) and have a more even distribution of the other trans-C n acids, but contain little or no RA (Parodi, 2004). 

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