Palm sterol

Consumption of food with sterols and their oxides is a health concern. Oxidation products of phytosterol, including epimers of 7-ketositosterol and 7-hydroxycampes-terol, 7-ketocampesterol, epimers of 5,6-epoxy-sitosterol, 5,6-epoxycamposterol, 24 a-ethylcholestane-3(3,5,6 (3-triol, and 24 a-methylcholestane-3(3,5,6 (3-triol, in deep-fried potato chips in palm oil, sunflower oil, and high oleic sunflower oil were quanhtahvely analyzed by PTLC followed by GC and GC-MS [73]. 

Many plants contain estrogenic compounds. Estrone (Fig. 11.11) is found in seeds of date palms, pomegranates, and apples, and estriol in willow. These may be merely by-products of sterol metabolism, or serve a particular function. Harborne (1993) proposed that plants synthesize steroid hormones to deter feeding by mammals. Estrogenic compounds in plants are thought to upset the delicate hormone balance of mammals. 

No comprehensive comparison has been made of the proportions of the free and esterified sterols in cocoa butter with those of fats likely to be used in cocoa butter adulteration. However Gordon and Griffiths (1992) examined the sterol esters of palm kernel oil by isolation with TLC followed by GC and HPLC. They pointed out the problem of co-elution of triacylglycerols with steryl esters with GC. The characterization of esters of triterpene alcohols in CBA fats might well prove useful where the use of fats containing shea is suspected. 

Souter, M., Topping, J., Pullen, M., Friml, J., Palme, K., Hackett, R., Grierson, D. and Lindsey, K. (2002) Hydra mutants of Arabidopsis are defective in sterol profiles and auxin and ethylene signaling. Plant Cell, 14,1017-31. 

Avocado Persea americana). The avocado grows in tropical and subtropical countries between 40°N and 40°S and is available particularly from California, Florida, Israel, New Zealand, and South Africa. Like the palm and the olive, lipid is concentrated in the fruit pulp (4—25%) from which it can be pressed. There is very little oil in the seed (2%). The oil is used widely in cosmetic products as it is easily absorbed by the skin, and its unsaponifiable material is reported to provide some protection from the sun. It is also available as a high-oleic speciality oil for food use. It is rich in chlorophyll, making it green before processing. It contains 16 0 (10-20%), 18 1 (60-70%), and 18 2 (10-15%) as its major fatty acids. Its unsaponifiable matter, total sterol, and tocopherol levels have been reported (74-78). 

Minor Components. The carotenoids, tocopherols, sterols, phosphatides, triterpe-nic, and aliphatic alcohols form the minor constitutents of palm oil. Though present in less than 1 % altogether in palm oil, nevertheless they play a signihcant role in the stability and rehnability of the oil, in addition to increasing the nutritive value of the oil. 

In terms of sterols, palm oil contains far less cholesterol than many other vegetable oils as shown in Table 9. Table 10 gives the sterol composition of crude and... 

TABLE 10. Sterol Composition of Crude and Refined Palm Oil and Their Products (ppm) (11). ... 

Sterol Coconut Corn Cotton Seed Linseed Olive Pam Palm Kernel Peanut Rape Seed Rice Bran Saf- flower Sesame Shea Butter Soy Bean Sun flower Wheat Germ... 

The unsaponifiable matter of soy, corn, canola/rapeseed, sunflower, cottonseed, peanut, and palm ranges from 10-30%, and it is composed of 40% phytosterols and 15% tocopherols (199-202). The temperature, duration, quantity of skimming vapor, and the extent of vacuum used for deodorization are the parameters that greatly influence the quality and quantity of DOD. The low content of tocopherols and sterols in the DOD often requires a concentration step however, if the starting material is soybean, this is not an issue because of the high concentration of these compounds. 

Palm fatty acid distillate (PFAD) is a valuable by-product of palm oil processing, from which the production of tocopherols and tocotrienols is technically feasible (Ong and Choo, 1997). PFAD is wildly abundant, as palm oil is the second largest oil produced in the world. It contains 4000-8000 pg/g total vitamin E compounds, which is up to 10 times as much as crude palm oil contains (Tan, 1989 Ong and Choo, 1997). The tocopherol and tocotrienol profiles of PFAD and crude palm oil are similar, consisting of about 85% of tocotrienols, i.e., y-tocotrienol > a-tocotrienol > 8-tocotrienol (Tan, 1989). Because of cholesterol-lowering properties (Lane et al., 1999), the high level of tocotrienols makes PFAD an important source, because most other natural sources are devoid of tocotrienols. Fatty acids and esters, sterols and squalene are removed from PFAD as described above. Finally, the vitamin-E-rich product is purified and deodorized to yield a tocopherol/tocotrienol-rich product of 95-99% purity. 

Waxes are complex mixtures of nonpolar lipids. They are protective coatings on leaves, stems, and fruits of plants and the skin and fur of animals. Esters composed of long-chain fatty acids and long-chain alcohols are prominent constituents of most waxes. Well-known examples of waxes include camauba wax, produced by the leaves of the Brazilian wax palm, and beeswax. The predominant constituent of camauba wax is the wax ester melissyl cerotate (Figure 11.5). Triacontyl hexadecanoate is one of several important wax esters in beeswax. Waxes also contain hydrocarbons, alcohols, fatty acids, aldehydes, and sterols (steroid alcohols). 

Crude palm oil is rich in minor components such as carotenoids, tocopherols, tocotrienols, sterols, phospholipids, triterpene alcohols, squalene, aliphatic alcohols and aliphatic hydrocarbons (Goh et al. 1985). The major components of interest are the carotenes, tocopherols, tocotrienols, sterols and squalene (Table 3.10). Carotenes and tocopherols are antioxidants and stabilise the oil against oxidation. During refining, the bleaching and steam deodorisation processes partially remove some of these valuable components. The amounts retained in the refined oils depend on the conditions of refining. 

Table 3.15 Sterol content and composition of palm oil products... 

Downes, M.J. (1982) Determination of sterol composition of crude vegetable oils. Part II. Palm oil and palm oil products. Leatherhead Food R. A. Tech. Circ., No. 781, pp. 4-5. 

Siew, W.L. (1990) Palm oil sterols, in Palm Oil Developments, Malaysian Palm Oil Board, Malaysia, pp. 18-19. 

This is the State tree of South Carolina, being the only palm indigenous to the east coast of North America. Its seeds (which are used to derive the pharmaceutical) are rich in fatty acids, their esters, and sterols. The extract of these seeds is recommended for mild symptoms referable to the prostate, without pharmacological rationale, and with the danger that patients will use the product to temporize for symptoms that could lead to the early diagnosis of malignancy. The doses administered are usually insufficient to reduce the absorption of oral fat-soluble drugs, but it would seem wise to separate the administration of vitamin D, warfarin, etc. and this complementary therapy. 

Comparison of the sterols and sterol esters of coconut and palm kernel oils have showed sufficient differences to form a basis for distinguishing between the two oils. Sterols were isolated as the digitonides and analyzed using packed-column GLC. Sterol esters, separated by preparative TLC, were analyzed by temperature-programmed capillary GLC (50% phenyl 50% methlypolysi-loxane stationary phase) and reversed-phase HPLC. Palm kernel oil displayed two major peaks, apparently due to campesteryl myristate and unresolved sitosteryl myristate/avenasteryl palminate, which were present at lower levels in the coconut oil. In addition, variations in the concentrations of other components were observed. 

Serenoa repens (Bartram) Small (saw palmetto) is an herb that is most commonly used to treat problems related to benign prostatic hyperplasia (BPH). The medicinal element of saw palmetto is taken from the partially dried ripe fruit of the American dwarf palm tree, which is indigenous to the coastal regions of the southern United States, from the Carolinas and Florida to California. BPH is a nearly universal result of the aging process in men. Saw palmetto is widely used in other countries for example, it is used in 50% of treatments for BPH in Italy and in 90% of such treatments in Germany. The active part of the plant is the sterols and free fatty acids found in the berry. It is unclear which components are the most active, and the mechanism of action is not fully understood. Some of the mechanisms proposed include anti-inflammatory activity, blocked conversion of testosterone to dihydrotestosterone and prostate epithelial involution similar to effects... 

Table 3.81 Sterol composition of palm oiP (Rossell etal., 1983)...

The minor components of palm oil include carotenoids (Table 3.79) tocopherols (Table 3.80), sterols (Tables 3.81 and 3.145), triterpene alcohols (Table 3.147) and methylsterols (Table 3.146). Average figures for the minor components in plantation oils are given in Tables 3.79-3.81. 

Other common food lipids are the sterols and to-copherols. Sterols are generally present in natural oils as both the free sterol and sterol fatty esters. Animal fats exhibit solely cholesterol while plant lipids contain a range of phytosterols. Tocopherols are found in vegetable oils as a mixture of four iso-mers a-tocopherol (true vitamin E) and 3-, y-, and d-tocopherol. Four unsaturated analogs, tocotrienols, exist with the same numbering terminology and are particularly abundant in palm oil. 

Plant and animal N.f. can be distinguished analytically because they are associated with different sterols, e. g. phytosterol in plant fat and cholesterol in animal fat. They are of equal nutritional value, however, provided that the same vitamins and essential fatty acids are present. Plant N.f. are most abundant in seeds (40-45 % in rapeseed, poppy seed and linseed). Olives contain up to 25% N.f. The most important fruit oils are palm and olive oils the most important solid seed N. f. are coconut and palm seed fats and cocoa butter. The seed oils of cotton, com, sunflowers, peanuts, soy, almonds, sesame, flax (linseed), poppies, rape, mustard and Ricinus are economically important. 

Fruits obtained from this species of palm are very rich in fats, including oleic, lauric, myristic, capric, palmitic, stearic (all saturated) and linoleic fatty acids as well as ethyl esters of these fatty acids. The lipophilic constituents also include numerous sterols, diterpenes, sesquiterpenes, triterpenes, carotenoids and high-molecular-weight alcohols (Winston 1999). Water-soluble polysaccharides with high molecular weights are also found in the seed, but not in the widely used liposterolic extracts. 

J.P. Clark, Tocopherols and sterols from soybeans, Upid Technology, 1996, 8,111-114. K.Sundram and Abdul Gapor Md. Top, Vitamin E from palm oil its extractirm and nutritional properties. Lipid Technology, 1992, 4, 137-141. E.N. Frankel, Lipid Oxidation, The Oily Press, Dundee (1998). T. Netscher, lipid Synthesis and Manufacture (ed. F.D. Gunstone) Sheffield Academic Press, Sheffield (1999) pp.250-267. 

Sterols are separated as 3,5-dinitrobenzoic acid derivatives by thin layer chromatography and, after reaction with 1,3-diaminopropane, are determined quantitatively with high sensitivity in the form of a Meisenheimer adduct. Sterols and triterpene alcohols are silylated and then analysed by gas chromatography. One application of this method is illustrated by the detection of 5% coberine in cocoa butter (Fig. 3.44). The compounds a-amyrine and lup-20(29)-en-3P-ol (Formula 3.113a and 3.116) serve as indicators. They are present in much higher concentrations in some cocoa butter substitutes than in cocoa butter. Coberine is a cocoa butter substitute made by blending palm oil and shea butter (the shea is an African tree with seeds that yield a thick white fat, shea butter). 

Polyunsaturated vs. Saturated Fats. Most vegetable oils, with the exception of cocoa butter, coconut oil, and the palm oils, are more unsaturated (they have higher iodine numbers) than most fats from animals. Marine animals and fish may also be rich in unsaturated fats. Also, vegetable oils are free of cholesterol, which is suspected of contributing to the development of atherosclerosis and heart disease, when excessive amounts of the sterol are consumed by susceptible people over long periods of time. Furthermore, the substitution of substantial amounts of vegetable oils for saturated... 

In one study, palm kernel and coconut oils samples were analyzed for triglyceride, fatty acid, sterol and tocopherol compositions. The melting points were also determined. Statistical analysis of the results has shown that a combination of values from the carbon number analysis differentiates palm kernel and coconut oils. Furthermore, carbon number analysis can be used to determine the proportion of each in a blend (Rossell et al., 1983). 

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