Linoleic plant content

The average oil content of commercial com hybrids planted in the com belt has declined over the last 50 years from 4.8-5.0% to 4.4%.52 The apparent cause of this decline has been widespread use of one or two high yielding, low oil content corn inbreds. At the same time, the iodine value of com oil has increased from 122-124 to 128-130, equivalent to a linoleic acid content increase from 55% to 60%. This change is apparently associated with the decline in oil content.53... 

Substituted pyridazinones induce a specific decrease in the linolenic acid content accompanied by an increase in the linoleic acid content of plant membranes. The most distinct effect among many 5-substituted pyridazinones (78MI7 83M15 86MI21 87MI17) was shown by 4-chloro-5-... 

An excellent example of the implementation of SCFF to obtain palmitic acid from a plant source is the work of Brunner and Machado [7,72]. They conducted a detailed analysis on the fractionation of fatty acids from palm fatty acid distillates (99 % FFA (mainly palmitic, oleic and linoleic acid), 0.9 % squalene and 0.1 tocopherol) starting with a phase equilibrium analysis through to pilot plant studies and experimental verification of the separation. They postulated, from the phase equilibrium studies, that squalene and palmitie acid would be preferentially extracted and verified their postulation experimentally. They also considered a pseudo-binary mixture separation where palmitic acid is to be separated from oleic and linoleic acid and showed, using separation factors that this is possible. On pilot plant scale they showed that such a separation is feasible and balanced yield and extraet quality. At their optimum conditions (373 K, 29 MPa, extract to raffinate ratio of 1.2) they obtained an extract where the palmitic acid content was enriched from 52.5 % in the feed to 74.4 % in the extract and the oleic and linoleic acid content enriched from 46.3 % in the feed to 59.0 % in the raffinate. Squalene was also enriched in the extraet Irom 0.6 % in the feed to 1.2 % in the... 

Table 10.2 The linoleic add content of some animal fats and plant oils (as an approximate percentage of total fatty acids)...

Regarding the compositional differences shown for animal products, whether they are important for health depends, as for the plants, on the overall composition of the diet of the people who eat them. The vitamin E content in milk is far too small for relevant differences to affect health (Nielsen ef al. 2004), and too little is known about the dose-response relations of the impact of conjugated linoleic acids on health. However, the increased vitamin E level may still be important to prevent oxidation of the fat, a problem that can be exacerbated by increased levels of polyunsaturated fatty acids (Dhiman ef al. 1999, Nielsen ef al. 2004). However, while oxidised milk is clearly not good for health, its rancid taste and smell allows detection and rejection before consumption and thus prevents harm to health, similar to plant toxicants. Also in line with the plants, while the use of roughage is clearly more extensive in organic farming, some conventional farmers use almost identical feed compositions and are therefore likely to produce the same quality of products in this respect. 

Safflower Oil, Unhydrogenated, occurs as a light yellow oil. It is obtained from the plant Carthamus tinctorius (Fam. Asteraceae) by mechanical expression or solvent extraction. 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 is a liquid at 21° to 21°, but traces of wax may cause the oil to cloud unless removed by winterization. Safflower Oil has the highest linoleic acid [(Z),(Z)-9,12-octadecadienoic acid] content (typically about 78% of total fatty acids) of any known oil. It is free from visible foreign matter at 21° to 21°. 

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... 

In 1957, scientists in Australia and California independently reported a mutation that came to be known as oleic safflower (54-56). This mutation occurred naturally and produces a plant and seed that look exactly like linoleic safflower, except for an oil whose fatty acid distribution is a mirror image of linoleic safflower oil (Table 2). The initial oleic safflower variety released by Knowles, UC-1 (57), was lower in oil content and had a poorer yield than conventional varieties available at the time. This meant that oleic safflower oil was initially sold at a premium. But agronomic research has since produced varieties that equal or even exceed normal safflower in yield and that are comparable in oil content. 

Sunola is a miniature type of sunflower developed by the Agriculture Canada Research Station in Saskatoon as a sowing alternative for areas where growth of traditional sunflower is not viable. It is the result of persistent selection of open-pollinated varieties. Plant height is small (60-90 cm), and heads are 8-13 cm in diameter. Ripening time is 99-103 days— three weeks shorter than for most sunflower varieties. Sunola has a high oil content (similar to that of the best hybrids) and a higher content of linoleic acid (72-74%) than any other commercial sunflower. 

In a study of 92 Finnish edible and nonedible plant materials, a total of 15 berry samples were screened for antioxidant activity (Kahkonen et al., 1999). The activity was compared with the total phenolic content of the samples. Inhibition of methyl linoleate oxidation was used as a measure of antioxidant activity of berry acetone extracts and total phenolics determined by the Folin-Ciocalteau method as GAE/g dry matter of extracts. Berry extracts were high in antioxidant activity among the... 

In plants, triacylglycerols constitute an important energy reserve in fruits and seeds. Because these molecules contain relatively large amounts of unsaturated fatty acids (e.g., oleic and linoleic), they are referred to as plant oils. Seeds rich in oil include peanut, com, palm, safflower, and soybean. Avocados and olives are fruits with a high oil content. 

Typical fatty acid composition of commodity soybean oil, in comparison with the other major vegetable oils, is shown in Table 2.3. Soybean oil has a high content of linoleic acid, and a lower level of linolenic acid. These are both essential fatty acids for humans and therefore of dietary importance, but they are also the cause of oxidative instability of this oil. Processing techniques, such as hydrogenation and lipid modification through traditional plant breeding or genetic transformation, have been used to modify the fatty acid composition to improve its oxidative or functional properties. 

Commodity soybean oil is composed of 61% polyunsaturated fatty acids, 25% monounsaturated fatty acid and 15% saturated fatty acids. The essential fatty acids linoleic (18 2, n-6) and a-linolenic (18 3, n-3) acids account for 89 and 11 % of the total essential fatty acids from this source. The n-6 acid content in soybean oil is slightly lower than that in com and sunflower oils, but it is more than double that in canola oil. Soybean and canola are the only two common plant oils that have a considerable amount of the n-3 linolenic acid. 

---