Vegetable oils chemical composition

Various tests and analytical methods are used for the characterisation and evaluation of the properties of vegetable oil-based polymer composites. Mechanical tests for properties such as tensile, flexural, compressive, impact, hardness and wear are carried out by a universal testing machine (UTM), and by equipment for testing impact, hardness, abrasion loss, and so on. Weather and chemical resistance tests are performed in UV/ozone, an artificial environmental chamber and in different chemical media. Water uptake and biodegradability tests are carried out by standard ASTM methods. Biodegradability and biocompatibility may be studied by the same procedure as described in Chapter 2. However, in practice only a few such studies have been performed for vegetable oil-based composites. 

From the viewpoint of fundamental research, pure chemical entities should be used as additives. However, taking into account the application of the results obtained, the tendency was to use low-cost lubricating substances having certain performance characteristics. Therefore, the decision was made to use products manufactured on a large industrial scale. Such products are mixtures of compounds of similar structure. This results from the fact that the reactants in the case of such compounds are, for example, vegetable oils whose composition can vary. However, such an approach to investigations requires each time a detailed physicochemical analysis of the compositions obtained. 

An experiment describing the analysis of the triglyc eride composition of several vegetable oils is described in the May 1988 issue of the Journal of Chemical Education (pp 464-466)... 

Okra, Hibiscus escuentus L. The immature pods of okra are popular as a vegetable and okra is also used for the ability to thicken soups and stews, and for fiber and oil. Notmuch is known about okra most workers concentrate their research on the chemical composition (26-29) of the mucilaginous materials found in the pod (30) stalk, nutritional properties (31). Research has also been conducted on the developmental properties of the okra seed (32). This paper is the first report of the chemical composition of auxin conjugates in okra pods bound to nitrocellulose membrane. 

All of the studies were conducted with weanling, male albino rats of the Sprague-Dawley strain (Holtzman company). The basal diet used for these studies consisted of casein, starch, vegetable oil, vitamin and mineral mixtures, and cellulose. The Wesson Modification of the Osborne-Mendel mineral mixture was used in all studies. This mineral mixture contained no zinc, but it was adequate in the other minerals required by the rat. Most of the non-zinc-supplemented diets used in the various experiments contained approximately 7 ppm zinc. The level of mineral mixture used in the basal diets was 4%, and based on the chemical composition of the mixture, the basal diets contained approximately 0.57% calcium and 0.41% phosphorus ... 

Barium hydroxide is used to produce barium soaps which are additives for high temperature lubricants. Other chemical applications include refining of vegetable oils vulcanization of synthetic rubber in drilling fluids in corrosion inhibitors as an ingredient in sealing compositions in plastics stabilizers for softening water and to prepare other alkalies. 

Fatty acids react with alkaline catalysts to form catalytically inactive soaps (3). The chemical reaction consumes one mole of fatty acid per mole of alkaline catalyst. Although fatty acid composition of the starting material varies, the content determined by titration reflects the amount of catalyst that would be consumed in a chemical reaction. By calculation, it may be determined that one gram of fatty acid (expressed as oleic acid) will react with about 0.2 g of anhydrous potassium hydroxide or 0.14g of anhydrous sodium hydroxide. Often, additional catalyst must be added to esterify a vegetable oil containing higher levels of fatty acids (3). Conversely, acid catalysts are not inactivated by fatty acids (3). In a unique reaction, fatty acids produced during biodiesel manufacture are actually used as a catalyst in their own esterification (see below). 

Use Organic synthesis and chemical intermediate solvent for waxes, vegetable oils, natural and synthetic resins, cellulose esters and ethers polishing compositions brake fluids solvent degreasing antiseptic. 

The composition of major sterols in common vegetable oils is presented in Table 4.8. Brassicasterol is a major sterol in rapeseed and canola oils and as it is unique to brassica oils it is often used to detect adulteration of other oils with rapeseed/canola oils (Strocchi 1987 Ackman 1990). Sterols are affected by processing and about 40% of these components can be removed from the oil during deodorization. Refining also causes changes in the chemical structure of sterols (Kochar 1983 Marchio el al. 1987). 

Fixed oils.—Tliese substances are designated as xed, to distinguish them from other vegetable products having an oily appearance, but which differ from the true oils in their chemical composition and in their physical properties, especially in that they are volatile witiiout decomposition, and are obtained by dis ation, while the fixed oils are obtained by expression, with or without the aid of a gentle heat. 

OTHER COMMENTS used as a solvent for waxes, vegetable oils, resins, cellulose esters, ethers, brake fluids, polishing compositions, and degreasing operations useful as a chemical intermediate in organic synthesis also used as an antiseptic. 

The fats and oils obtained from various sources differ from one another in the proportion of the several esters present in each. This difference in composition results in a difference in physical properties, such as specific gravity, viscosity, index of refraction, and melting point. All the fats and vegetable oils are soluble in ether, however,—a fact made use of in the analysis of foods to separate fats from the other constituents of food-products. As the physical properties of a fat or an oil obtained from a definite source are more or less constant, the determination of these properties is of value in the analysis of such substances. The chemical analysis of fats and oils is based upon determinations of the proportion of unsaturated compounds present, of the relation between the acids of low and high molecular weight obtained on hydrolysis, and of the proportion of substances which do not undergo hydrolysis. This statement will be made clearer by a brief consideration of a few of the more important methods employed in the analysis of fats and oils. 

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