Wheat tocopherols

Wheat Tocopherol and Phenomenex Luna Fluorescence NR NR NR Hussain et al. 

In inner layers, changes are much the same as during boiling. Tocopherols and tocotrienols present in wheat and rye are partially destroyed during baking. In ordinary wheat bread, losses of a-tocopherol amount to about 25%, but in the case of rye bread, prepared by traditional technology, a loss of about 50% was reported (Piironen et al, 1987). Losses of natural antioxidants in coffee brews and tomato puree were also observed (Nicoli et al, 1997). 

Another fat-soluble vitamin, E, was found by Evans and Bishop in 1923. Pregnant rats on a defined diet (alcohol-extracted casein, cornstarch, and lard) supplemented with butter (vitamins A and D) and yeast extract (vitamin B group) produced few young because of fetal resorption. Male rats on the same diet were sterile. The disorders, which have not been identified in man, were corrected by wheat-germ oil, from which tocopherol, the active ingredient, was isolated in 1936. In spite of intensive investigations and a recognition that the vitamin is an antioxidant and destroyer of free radicals, the function of vitamin E remains obscure. 

Vitamin E (tocopherol) and related compounds only occur in plants (e.g., wheat germ). They contain what is known as a chro-man ring. In the lipid phase, vitamin E is mainly located in biological membranes, where as an antioxidant it protects unsaturated lipids against ROS (see p. 284) and other radicals. 

Standards. Pure standard-grade tocopherols (a-, y-, 5-tocopherol) are available commercially, but tocotrienol standards are not. Shin and Godber (1994) described a method to prepare tocotrienol standards with purity potentially >99% from wheat bran oils. 

Coenzyme Q10 and vitamin E are found in wheat germ. Furthermore, studies in mice have shown that administration of coenzyme Q10 elevate the level of mitochondrial a-tocopherol (Lass et al., 1999). Beal and his colleagues (2002) investigated the potential usefulness of coenzyme Q10 in animal models of PD, amyotrophic lateral sclerosis (ALS), and HD. It has been demonstrated that coenzyme Q10 can protect against striatal lesions produced by the mitochondrial toxins malonate and 3-nitropropionic acid. These toxins have been utilized to model the striatal pathology, which... 

Vitamin E (a-tocopherol) is most abundantly available in wheat germ oil and in small quantities in cereals, nuts, spinach, and egg yolk. Deficiency of vitamin E normally does not occur. Large doses of vitamin E are used to reduce the toxicity of vitamin A. Prolonged use causes delay in wound healing but significant... 

Wade et al. (1986) reported that BHA and BHT were effective in retarding oxidation of anhydrous milk fat but DL-a-tocopherol acted as a pro-oxidant. Natural antioxidants in betel and curry leaves have also been reported to retard oxidation of anhydrous milk fat (Sharma, 1981 Parmer and Sharma, 1986). Amr (1991) reported that turmeric and wheat grits were as effective as BHA and BHT in controlling oxidative rancidity in sheep s anhydrous milk fat for up to 4 months. However, rosemary, sage, rue and fennel exerted pro-oxidant effects. Quercetin and rutin are reported to be efficient antioxidants in butter (Eriksson, 1987). 

Table 9-10 Tocopherol Content of Wheat and Its Milling Products...

Zhou, K. Yin, J. Yu, L. 2005. Phenolic acid, tocopherol and carotenoid compositions, and antioxidant functions of hard red winter wheat bran. J. Agric. Food Chem. 53 3916-3922. 

Gelmez N. Kincal N.S. Yener M.E. 2009. Optimization of supercritical carbon dioxide extraction of antioxidants from roasted wheat germ based on yield, total phenolic and tocopherol eontents, and antioxidant aetivities of the extraets. J. Supererit. Fluid 48 217-224. 

Unsaponifiable Components Wheat germ oil is quite rich in unsaponi-fiable compounds, in particular phytosterols and tocopherols (Table 7). Small quantities of triterpenols, n-alkanols, carotenoids, and hydrocarbons are also present in the unsaponifiable fraction of the oil. Tocopherols and n-alkanols are commercially the most important unsaponifiable components in WGO. 

Tocols Tocopherols constitute about 18% of the unsaponifiable fraction of WGO (Table 7). Wheat germ oil is one of the richest natural sources of... 

The fatty acid composition of the extracts was not affected by temperature, pressure, and the extraction method (Table 4). Supercritical carbon-dioxide-extracted oil samples had similar fatty acid composition to that of the Soxhlet-extracted oil (Table 4). All of the wheat germ extracts consisted of about 56% linoleic acid (18 2 n-6), which is an essential fatty acid (Table 4). The total unsaturated and polyunsaturated fatty acid (PUFA) content of the wheat germ oil was about 81 % and 64%, respectively. The SC-CO2 extraction of wheat germ resulted in extracts with similar tocopherol and tocotrienol compositions to those of the Soxhlet extracts (Table 8) (50). These results indicate that SC-CO2 technology can be used for extraction and fractionation of WGO components to obtain products with high quality. 

Good sources of vitamin E are vegetable oils, such as com, soy, and peanut oii. Animal fats, such as butter and lard, contain lowrer amounts of the vitamin. The content of the most important form of vitamin E, a-tocopherol, in various foods is as follows. Com oil contains about 16 mg of a-tocopherol per 100 g sunflower oil 50 mg/100 g, wheat germ oil 120 mg/100 g and fish, eggs, and beef 0.5 to 2,0 rng/100 g. In plants, a-tocopherol resides in chloroplasts, while other forms of tocopherol ( i-, y-, and 5-tocopherol) occur elsewhere in the plant cell. Tocotrienols, which also have vitamin E activity, are not found in the green parts of plants, but in the bran and germ of seeds... 

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