Tocopherols sources

Figure 9-7 Chemistry of the Tocopherols. Source From R. A. Morton, The Chemistry of Tocopherols, in Tocopherole, K. Lang, ed., 1967, Steinkopff Verlag, Darmstadt, Germany.

Tsimidou, M. Z. (2012). Virgin olive oil (voo) and other olive tree products as sources of a-tocopherol, updating and perspective. Editors Angel Catala Tocopherol Sources, Uses and Health Benefits. 

The quaHty, ie, level of impurities, of the fats and oils used in the manufacture of soap is important in the production of commercial products. Fats and oils are isolated from various animal and vegetable sources and contain different intrinsic impurities. These impurities may include hydrolysis products of the triglyceride, eg, fatty acid and mono/diglycerides proteinaceous materials and particulate dirt, eg, bone meal and various vitamins, pigments, phosphatides, and sterols, ie, cholesterol and tocopherol as weU as less descript odor and color bodies. These impurities affect the physical properties such as odor and color of the fats and oils and can cause additional degradation of the fats and oils upon storage. For commercial soaps, it is desirable to keep these impurities at the absolute minimum for both storage stabiHty and finished product quaHty considerations. 

Unesterified tocopherols are found in a variety of foods however, concentration and isomer distribution of tocopherols vary gready with source. Typically, meat, fish, and dairy contain <40 mg/100 g of total tocopherols. Almost all (>75%) of this is a-tocopherol for most sources in this group. The variation in the content of meat and dairy products can be related to the content of the food ingested by the animal. A strong seasonal variation can also be observed. Vegetable oils contain significant levels of y-, P-, and 5-tocopherol, along with a-tocopherol (Table 3). 

Oil source Total tocopherols a-Tocopherol y-Tocopherol (3-Tocopherol 5-Tocopherol... 

As mentioned previously, in the AMD retina iron metabolism is compromised (He et al., 2007 Wong et al., 2007). Thus, it is of interest to determine the effects of potential antioxidants in the presence of iron. In an in vitro study of ARPE-19 cells, addition of a lipophilic iron complex led to about a ninefold increase in the photosensitized yield of 7a,(3-cholesterol hydroperoxides (Wrona et al., 2004). In the presence of the iron, ascorbate exerted pro-oxidant effects, while the effects of a-tocopherol, zeaxanthin, or their combination were still protective (Wrona et al., 2004). Thus, it appears that the effects of potential antioxidants are strongly dependent on the sources of oxidative damage. The same antioxidant may be protective under certain conditions and exert deleterious effects when the conditions are changed. Therefore a detailed understanding of the sources of the oxidative damage is required in order to design an adequate antioxidant mixture. 

There exists a list of permitted additives. This list is concerned only with chemical synthetics (substances obtained by a chemical reaction other than degradation). It means that the substances on the list are those which either do not occur naturally or are not obtained from natural sources. Of the substances which are not on the list it is not always possible to decide whether these may be used in food. The antioxidants and foodstuffs in which a limited amount of antioxidant is permitted are given in Table 12.11. Only the above-mentioned foods may contain antioxidants, except -tocopherol which may be generally used in foods as an antioxidant. 

Lipids are important components of the diet fatty acids are the higher energetic source as they ensure 9kcal/g. Furthermore, some peculiar fatty acids themselves and several components of the unsaponifiable fraction are biologically active molecules, as they can act as vitamins (tocopherols— vitamin E), provitamins (carotenes—vitamin A, cholecalcipherol—vitamin D), vitamin-like (essential fatty acids), and hormones or hormone precursors (sterols—steroidal hormones). 

The main sources of these compounds are vegetable oils, unprocessed cereal grains, and nuts. The vitamin formulations that may be added to foods are o-a-tocopherol, OL-a-tocopherol, o-a-tocopheryl acetate, oL-a-tocopheryl acetate, and o-a-tocopheryl acid succinate [403],... 

Table 6.4 summarizes the concentrations of a range of endogenous (i.e., nondietary) simple phenols, including a-tocopherol, and ascorbate in plasma from healthy individuals. The total simple phenol and ascorbate concentration is between 159 and 380 pM. The maximum additional concentration that is likely to be achieved from dietary sources, 3 to 22 pM, is marginal by comparison adding only between 0.3 and 5% if it is assumed, quite reasonably, that the typical mean intake is taken over three equal meals. Many people consume a much smaller quantity of dietary PPT and even those consuming double the... 

Wehmeyer et al. (1969) published results on the content of B vitamins (thiamine, riboflavin, and nicotinic acid), vitamin C, and p-carotene and foimd that the morama bean is a good source of both B vitamins and vitamin C, but a poor source of p-carotene. Holse et al. (2010) investigated the content of the eight vitamin E isomers and found that the vitamin E composition in morama beans is dominated by y-tocopherol with 59-234 ng/g, followed by a- and p-tocopherols with 14- 8 gg/g and 1.1-3.3 ng/g, respectively. Eurthermore, traces of 8-tocopherol as well as p- and y-tocotrienols were present in some samples. The remaining two tocotrienols (a- and 8-) were not present in the beans. The presence of a-, p-, and y-tocopherols in the morama bean was also foimd by Mitei et al. (2009) who examined morama oil and by Dubois et al. (1995) who examined two samples of T.fassoglense. 

Vegetable oils are rich sources of vitamin E, whereas liver and eggs contain moderate amounts. The RDA for a-tocopherol is 10 mg for men and 8 mg for women. Vitamin E requirement increases as the intake of polyunsaturated fatty acid increases. 

Synthesis of the enantiomerically pure (5)-chroman-2-carbaldehyde (257) follows a similar route to the above, but the chirality is introduced through the ketone (256) (82CC205). A particularly interesting feature of this synthesis is the derivation of the diol (255) from 2-methyl-3-(2-furyl)propenal using fermenting baker s yeast. Furthermore, the fermentation also produces the chiral alcohol (258), a source of the C15 unit which is the second component along with the aldehyde (257) in an a-tocopherol synthesis. 

Shin, T.S. and Godber, J.S. 1994. Isolation of four tocopherols and four tocotrienols from a variety of natural sources by semi-preparative high performance liquid chromatography. J. Chromatogr. A 678 49-58. 

The acetate ester of a-tocopherol, rather than the free alcohol, is used as a food supplement on account of its greater stability. Both 7 7 f -a-tocopheryl acetate and totally synthetic all-rac-a-tocopheryl acetate are commercially available, the former having a biological activity of 1.36 IU/mg and the latter 1.00 IU/mg (44). The / / / -a-tocopheryl acetate is obtained by extraction from vegetable oils. Since it is not isolated without some chemical processing, it cannot legally be called natural, but it can be described as derived from natural sources. 

It is fortuitous that indigenous concentrations of vitamin E in the principal food sources are on the order of mg rather than yug/100 g, for the tocopherols and tocotrienols exhibit relatively low intensities of UV absorption. Individual vitamers are characterized by a slightly different absorption maximum within the wavelength range of 292-298 nm in ethanol. Published A] m values for the tocopherols at their Amax in ethanol are a-T 70-73.7 at 292 nm, (3-T 86-87 at 297 nm, y-T 90-93 at 298 nm, and <5-T 91.2 at 298 nm (126). The different absorption characteristics among the vitamers necessitates the running of individual standards for accurate quantitation of each vitamer. The absorption intensity of a-tocopheryl acetate is lower still with an A j m value of only 40-44 at the Amax of 285.5 nm (44). Reported minimum detectable quantities of a-, / -, y-, and (5-tocopherols at 295 nm are, respectively, 50 ng, 70 ng, 90 ng, and 130 ng (127). 

Indyk and Woollard (195) demonstrated that the removal of cholesterol from the un-saponifiable fraction of vitamin D-supplemented whole milk powder by methanolic precipitation and filtration was an adequate cleanup procedure, making semipreparative HPLC unnecessary. This simplified procedure was made possible by connecting two analytical columns in series. The tandem columns adequately separated vitamins D2 and D3 from one another and from vitamins A and E. The analysis of infant formulas (100) required cleanup by silica solid-phase extraction to remove the minor tocopherols and tocotrienols, which constituted potential sources of interference. 

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