Tocopherol requirement, fatty acid

Vitamin E may be indicated in some rare forms of anemia such as macrocytic, megaloblastic anemia observed in children with severe malnutrition and the hemolytic anemia seen in premature infants on a diet rich in polyunsaturated fatty acids. Also anemia s in malabsorption syndromes have shown to be responsive to vitamin E treatment. Finally, hemolysis in patients with the acanthocytosis syndrome, a rare genetic disorder where there is a lack of plasma jS-lipoprotein and consequently no circulating alpha tocopherol, responds to vitamin E treatment. In neonates requiring oxygen therapy vitamin E has been used for its antioxidant properties to prevent the development retrolental fibroplasia. It should be noted that high dose vitamin E supplements are associated with an increased risk in allcause mortality. 

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. 

The tocopherol requirement of humans is not known with certainty, but about 5 mg (7.5 IU) / day plus an additional 0.6 mg for each gram of polyunsaturated fatty acid consumed may be adequate. 

Figures 8-10 show the curves of tocopherol concentration in the residue (% w/w) vs the percentage of the distance on the evaporator (from the feed point) for feed flow rate ranging from 0.5 to 1.0 kg/h for the falling film molecular distillation unit. The initial tocopherol concentration was 8.50% (w/w). For a feed flow rate of 0.5 kg/h (Fig. 8), it can be observed that at the end of the distillation, the tocopherol concentration in the residue will be higher, at 150°C (about 15% [w/w]). At 160°C, at 80% of the distillation, the tocopherol concentration reaches a maximum and then decreases, because the tocopherols are already recovered in the vapor phase. Figures 8-10 show that by increasing the feed flow rate at the same temperature (160°C), the tocopherol concentration can increase until it doubles the initial concentration (for a feed flow rate of 0.6 kg/h). From this point, it decreases, requiring an increase in the temperature to concentrate more (for a feed flow rate of 1.0 kg/h at 170°C). For all feed flow rates (Figs. 8-10), at 180°C, practically all the tocopherols are found in the vapor phase. With this study, it is possible to observe which temperature is the best in order to recover the fatty acids (first step = 125°C) and, then, recover the tocopherols in the vapor phase (distillate) and the phytosterols in the liquid phase (residue) (second step = 170°C). At the lowest temperature (120°C) the tocopherol recovery was minimum (about 5%). By increasing the feed flow rate from 0.5 to 1.0 kg/h (100%), the quantity of tocopherol in the residue at 170°C, e.g., increases, which means that the process performance has decreased.

Whilst growth factors in the serum provide specific proliferative stimuli, studies with cultured cells have indicated other important components for cell proliferation [18]. For example, insulin is required to facilitate glucose and amino-acid uptake, and transferrin, which binds iron, makes it available to the cell. Serum is also believed to supply trace elements such as selenium, copper and zinc as well as fatty acids important for cell growth. Some serum components such as ascorbate, a-tocopherol, caeruloplasmin and albumin may serve important antioxidant functions [19]. 

Refined oil usually retains little phospholipid, but damaged beans can have a significant content of phosphatidic acid, and the amount of iron in the oil is related to the amount of phosphorus (24). During deodorization, considerable amounts of sterol and tocopherol may be removed from the oil. The proportion removed depends on deodorization conditions, but a 30% to 40% decrease is not unusual (25). Much of the hydrocarbons and squalene are lost to the deodorizer distillate as well. Free fatty acids in fully refined oil are required to be <0.05% and unsaponifiable matter < 1.5% (26). 

The deodorization of cocoa butter is necessary to reduce free fatty acid content and to give a product that satisfies the present day requirement of a neutral bland flavor. Deodorization is a suitable method for partially eliminating chlorinated insecticides from cocoa butter. The normal deodorization temperatures are in the range 160-180°C. The oxidative stability of various cocoa butters listed in Table 4 shows extremely high values, and these are unaffected during the deodorization process. Stability against oxidation depends on natural antioxidants present in cocoa butters. The tocopherol composition in Table 5 shows a predominance of... 

RDA for vitamin E was increased in the year 2000 by 50% from 10 to 15 mg/day for adults by the U.S. Food and Nutrition Board.Most European reference intakes are related to the polyunsaturated fatty acid intake. The changes in the United States were accompanied by some debate, critics arguing that this amount could not be met by the usual North American diet. For infants up to 6 months, an AI of 4mg/day was proposed, for infants 7 to 12 months an AI of 5mg/day and the RDA for children 1 to 18 years was set at 6 to 15 mg/day, dependent upon age. Another departure in the newer recommendations was that the daily requirement he met by RRR-a-tocopherol alone as the other forms of vitamin E are not converted to a-tocopherol and are poorly recognized by the a-tocopherol transfer protein in the liver. 

The in vitro oxidation products from tocopherol have been studied in detail although less is known about its in vivo metabolism. The oxidation of a-tocopherol is light-catalysed and accelerated by unsaturated fatty acids, metal salts and alkali. The structure of many of the products from chemical oxidation has been established (ref. 98). It is used in the form of the unnatural acetate in which form it may well be more chemically stable although the manifestation of antioxidancy requires the presence of the free phenol since its radical is stabilised by resonance and by steric effects with the participation of several contributory structures. It has been suggested, as mentioned earlier, that the activity of vitamins E and C are related synergistically and evidence from pulse radiolysis has supported this augmenting interaction on the effect of vitamin E (ref.130), depicted in the equation. 

Outlined below is a brief discussion on how SCFs can be used to achieve fractionations involving palmitic acid where the required separation is not (only) between fatty acids of differing chain length, but rather obtaining palmitic acid from a mixture of a wide range of compounds. In particular, this part of the chapter will focus on the reduction of FFA content of oils and the separation of palmitic acid from tocopherols, sterols and other components. 

The temperature for deodorization and deacidification is dependent on the vapour pressure of the compounds to be removed. Thus for low-molecular-weight fatty acids as found in palmkernel oil a temperature of 185 °C in batch equipment and 200 °C in continuous or semi-continuous plant will suffice for deodorization. Although, as stated earlier, carotene is substantially destroyed and removed at 240 °C, in practice temperatures of up to 270 °C are required to break down compounds formed by oxidation during storage. Temperatures should, however, be kept as low as possible, firstly to reduce losses and secondly to reduce the possibility of isomerization and other thermochemical reactions (Rossell et al. 1981 Eder, 1982). It should also be remembered that it is in the interests of the refiner to minimize the loss from the oil of natural antioxidants, tocopherols and tocotrienols. There is a point at which the advantage to shelf-life of removal of aldehydes and ketones is cancelled out by the loss of these antioxidants. 

Vitamin E is the name given to a number of structurally related compounds the most important of which is a-tocopherol. The vitamin is needed for mitochondrial electron-transport function and prevents oxidation of various compounds including polyunsaturated fatty acids and vitamin A. The dependence of vitamin E requirement on the amount of dietary polyunsaturated fatty acids has been fully discussed by Jager (1975). Traditionally, vitamin E has been known as the fertility vitamin. However, deficiency leads to serious changes in skeletal muscle, the blood system and other tissues before reproduction is impaired. The effects on different animals are described by Jager (1975). The topic of vitamin E is also covered by Scott (1978). 

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