Linoleic iodine value

As a reference, the iodine values of oleic, linoleic, and linolenic acids are 89.9, 181.0, and 273.5, respectively. Iodine values for free fatty acids are higher than for those that are part... 

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... 

Is the Iodine Value found in EN 14214 based on science It is certainly not so in an absolute way, but some relation cannot be denied. Frankel (2005) for example clearly states that oxidation stability is a function of two things the number of double bounds, and their position towards one another in the fatty acid. Oleic acid with one double bound oxidizes 40 times slower than linoleic acid with two double bounds, and one bis-allylic position in-between both. Linolenic acid with three double bounds separated with two bis-allylic positions oxidizes only 2.5 times faster than linoleic acid. Oxidation is a radical driven reaction, and the bis-allylic positions are a much more favorable point of attack than the allylic positions next to the double bound. 

The weight of bromine is independent of the amount (per cent) of linoleic acid in the sample, but it varies with the iodine value.1 For the purpose of this preparation, the amount of bromine (grams) may be calculated as 0.7 times the iodine value of the oil. This allows an excess of 10-11 per cent. 

The higher value for canola oil is caused, in part, by the replacement of erucic acid with octadecenoic acids, mainly oleic acid, accompanied by a slight increase in linoleic and linolenic acids (Table 13). The iodine value can also be calculated from fatty acid composition using the specific factors for each unsaturated fatty acid (61). The calculation method provides more accurate data than the iodine absorption assessment. 

The seed of perilla contains 31-51% of oil, which is similar in composition to flaxseed oil, with a higher contribution of PUFA of over 70% (Table 4). The oil is highly unsaturated, with an iodine value of 192-208-g iodine /100-g oil (Table 4). Perilla oil contains over 60% linolenic acid with equal amounts of both linoleic and oleic acids (Table 4). Specific gravity of this oil is higher than flax oil because of a higher contribution of PUFA. Other physical parameters of this oil reflect the composition of its fatty acids. 

The USDA published what may have been the first practical procedure for quickly determining if a truckload of seed is a linoleic or oleic variety (138). It involves squeezing a few seeds in a small hand-powered press to obtain a few drops of oil. A drop of oil is placed on the glass prism cell of a hand-held refractometer. The refractive index has a straight-line relationship with the iodine value or fatty acid distribution of the oil, hence it is easy to determine if the seed in question meets an oleic standard or not, so long as a temperature correction is applied. Recently, it has become simpler to compare the unknown sample to a known oil standard, eliminating the need to apply a temperature correction. Temperature corrections are difficult to measure accurately in the field under the time pressure of harvest. 

Watermelon seed oil was prepared and evaluated for its physicochemical properties (22, 23). The seed oil consisted of 59.6% linoleic acid (18 2n-6) and 78.4% total unsaturated fatty acids (Table 4). The predominant fatty acid in the oil was linoleic acid, which was followed by oleic, palmitic, and stearic acids. Linolenic, palmitoleic, and myristic acids were minor constituents. The refractive index, acid value, peroxide value, and free fatty acids of watermelon seed oil were determined to be 1.4696 (25°C), 2.82 (mg KOH/g oil), 3.40 (mequiv oxygen/kg oil), and 1.41 (% as oleic acid), respectively. The saponification value of watermelon seed oil was 201 (mg KOH/g oil), and its iodine value was 115 (g iodine/100-g oil), which was significantly higher than pumpkin at 109 (g iodine/lOO-g oil) (22, 23). 

Melon, Cucumis melo, is a member of the Cucurbitaceae family and grows best in tropical regions. The pulp of the fruit has pleasant flavor and taste, and the seeds are generally treated as waste however, medicinal effects have been reported for the seeds (24, 25). Hexane-extracted seed oil of Cucumis melo hybrid AF-522 was determined to contain 64 g of linoleic acid per 100 g of total fatty acids (Table 4) (24). Significant amounts of oleic, palmitic, and stearic acids were also detected in the melon seed oil. The specific gravity (28°C), refractive index (28°C), and iodine value of the seed oil were 0.9000, 1.4820, and 112, respectively, under the experimental conditions (24). Earlier in 1986, Lazos (25) extracted the oil from Cucumis melo seeds and examined its physicochemical properties (25). Linoleic acid was the primary fatty acid and accounted for 64.6% of the total fat (w/w), along with 20.1% oleic acid, and 14.7% total saturated fatty acids (Table 4). Iodine value and refractive index (40°) of the seed oil were 124.5 and 1.4662, respectively. 

The roasted red pepper seed oil contained an extremely high concentration of linoleic acid, approximately 74%, and a high total unsaturated fat level (Table 6) (37). The fatty acid profile was very similar to that of both goldenberry seed (Physalis peruviana L.) and safflower oils (36). The iodine value of roasted red pepper seed oil was determined to be 137-g iodine/lOO-g oil.This shows that there is a high degree of unsaturation in the oil. Oxidative stabilities of the roasted red... 

Properties A drying oil similar in properties and uses to linseed. Edible, iodine value approximately 160, d 0.923, refr index 1.470-1.472. Contains approximately 10% saturated fatty acids (palmitic and stearic), unsaturated acids present are linoleic, lin-olenic, and oleic. Saponification value 190-193. 

Brazilian palm oil appears to be more unsaturated, containing an average of 43.2% oleic and 11.5% linoleic acids with an iodine value of 58 (Table 3.1). The range is wider and iodine values vary from 50-63 (Tavares and Barberio 1995). These oils are likely to be of different oil palm variety. Elias and Pantzaris (1997) considered that the oils reported by Tavares and Barberio were rather... 

Iodine value Palmitic (%) Stearic (%) Oleic (%) Linoleic (%)... 

Iodine value 172-4. More stable to air oxidation than linoleic acid. Miscible with dimethylformamide. fat solvents, oils. 

Witting- and Horwitt, 1962). This was done by comparing diets which contain saturated fats and a minimum of added linoleic acid and diets adjusted to provide different larger amounts of unsaturated fatty acids (Table I). Peroxidizability of tissues was estimated by arbitrarily giving a value of 1, 2, 4, 8, and 8 to the relative peroxidizability of diene, triene, tetraene, pentaene, and hexaene, respectively. It had previously been noted that when little or no tocopherol was present in such diets, the rate of appearance of dystrophy was slowest on the coconut oil diet and most rapid on the cod liver oil diet (Century and Horwitt, 1960 Century et al., 1961). If no tocopherol was provided to diets equal in unsaturation in terms of iodine value, as supplied by monoene, diene, triene, and polyene in syn-... 

The triglycerides of linseed reflect its high linole-nate composition. A wide variation in linolenate content has been noted (Table 3.62). This is related both to variety and to climatic conditions during maturation, the colder the climate the higher the iodine value. Early work (Dillman and Hopper, 1943) has also shown that moisture deficiency during growth tends to reduce the iodine value. There is a close correlation between refractive index and iodine value (Zeleny and Coleman, 1936) (see also Schuster and Marquard, 1974). 

Soybean oil shows a wide variation in composition (Table 3.113). Strong interrelationships exist between the fatty acids. Linolenic and linoleic acids are directly correlated, linolenic and oleic acids are negatively correlated. Saturated acids range from 11 to 26% and are virtually independent of the iodine value (Howel and Collins, 1957 Sing, 1976 White etaly 1961). 

Because linolenic acid (a minor but significant component of soybean oil) with its n—3 (A 15) double bond furnishes undesirable flavours after oxidation and also because linoleic acid has a desirable dietary value considerable effort has gone into making catalysts with high linolenic/linoleic selectivity. For nickel catalyst this is only 2-3 but with copper catalysts it may be 15-20. Thus soybean oil, reduced to an iodine value of 110 for use as a salad oil, would contain <1% or 4-5% linolenate with copper or nickel catalysts respectively. 

Cedar nut oil n. Pinus cembra, from the seeds of which this oil is derived, grows prolifically in several parts of the world. The main constituent acids are linoleic, linolenic, and oleic acids, and the oil possesses useful drying properties. Iodine values up to 160 have been reported. 

Grapeseed oil n. Semidryfrig v etable oil. Of the fatty acids present, up to 55% may be linoleic acid. Approximate constants for oil from various sources are Sp gr of0.925/ 15°C, refractive index of 1.4899/15°C, saponification value of 190, iodine value of 125-157. 

---