Vitamin E is a group of eight lipid-soluble antioxidants (α-, β-, γ-, and δ- tocopherols and tocotrienols, collectively known as tocochromanols) that are synthesized in the plastids of plants, algae, and some cyanobacteria ( Mène-Saffrané and
Claire H. Luby, Rachael Vernon, Hiroshi A. Maeda and Irwin L. Goldman
Sofia Caretto, Angelo Parente, Francesco Serio and Pietro Santamaria
tocopherols, known as vitamin E, have been shown to carry out essential functions in slowing or preventing degenerative disease processes in humans ( Kaur and Kapoor, 2001 ; Traber and Sies, 1996 ). Of the four known tocopherol forms—α, β, γ, and δ
Kais S. Ebrahem, Daryl G. Richardson and Richard M. Tetley
Kernels in the shell were compared to bare kernels with pellicles, half nuts, blanched nuts, finely chopped nuts, and roasted nuts. Whole nuts and whole kernels were stable for up to two years of storage provided they had not been exposed to high temperatures. Nuts stored at low temperatures (0 and 5°C) did not lose significant amounts of vitamin E. Increasing surface area by dividing nuts or finely chopping them, increased the loss of vitamin E. Samples that had lower surface areas did not lose much vitamin E and peroxide value was low. Higher roasting temperatures caused losses in vitamin E and increased peroxide values at the beginning and during storage, even when stored at 0°C. Intact nuts and low storage temperatures did not show changes in fatty acid composition. High temperature treatments changed fatty acid composition, mainly decreasing linoleic initially and finally oleic acids.
Catherine Nicolle, Gérard Simon, Edmond Rock, Pierre Amouroux and Christian Rémésy
Carrot (Daucus carota L.) is ranked among vegetables as the most consumed and the best provitamin A provider. Moreover, carrot also contains vitamins, phenolic compounds, and other antioxidant micronutrients. The influence of carrot genetic background on the content of several micronutrients was investigated. Carotenoids and vitamins (C and E) were analyzed by HPLC in 20 varieties of carrot, and antioxidant activity of carrots was investigated with colorimetric methods (ORAC and Folin-Ciocalteu). There were large differences among cultivars in carotenoid content (0.32 to 17 mg/100 g of fresh weight). In yellow and purple carrots, lutein represents nearly half of the total carotenoids. By contrast, in orange carrots, β-carotene represents the major carotenoid (65%). The concentration of vitamin E ranged from 191 to 703 μg/100 g of fresh weight, whereas the concentration in ascorbic acid ranged from 1.4 to 5.8 mg/100 g. For all these components, dark-orange carrots exhibited the highest values. Significant differences among these 20 varieties were also recorded for mineral and total phenolic compound concentrations. Purple and dark-orange carrots could be preferred to usual carrot varieties to benefit from their specific micronutrients (anthocyanins, carotenoids, or vitamin E). ORAC is a complex reflection of phytomicronutrients but is not tightly linked to vitamin C levels, as shown for white carrots, which are rich in this vitamin.
Shiva Ram Bhandari, Bo-Deul Jung, Hum-Young Baek and Young-Sang Lee
., 2006 ). A number of phytochemicals that are present in peppers such as phenolics, vitamin C, vitamin E, and carotenoids may contribute to antioxidant activity and consequently show various pharmacological and nutritional activities ( Balasundram et al
Thomas C. Koch and Irwin L. Goldman
Carotenoids and tocopherols are health-functional phytochemicals that occur in a wide range of fruit and vegetable crops. These two classes of compounds are synthesized from a common precursor, geranyl-geranyl pyrophosphate, and are typically analyzed separately via high-performance liquid chromatography (HPLC) techniques. Because carotenoids and tocopherols are present in many edible horticultural crops, it would be advantageous to measure them simultaneously in plant tissues. Herein we report a one-pass reverse-phase HPLC method for extraction and analysis of carotenoids and tocopherols in carrot that can be extended to other high-moisture plant organs. Elution times ranged from 5 minutes for α-tocopherol to 24 minutes for β-carotene. This method improves the efficiency of analyzing these compounds by up to 50%, and should increase the efficiency of assessing carotenoid and tocopherol profiles in horticultural crops.
Carlos Calderón-Vázquez, Mary L. Durbin, Vanessa E.T.M. Ashworth, Livia Tommasini, Kapua K.T. Meyer and Michael T. Clegg
compounds that are known to confer a health benefit (carotenoids, β-sitosterol, and vitamin E). Avocados are a significant source of dietary phytosterols, in particular β-sitosterol, that has been shown to decrease cholesterol absorption in the intestine
Myung-Min Oh, Edward E. Carey and C.B. Rajashekar
-tocopherol methyltransferase (γ-TMT), and phenylalanine ammonia lyase (PAL) involved in the biosynthesis of vitamin C, vitamin E, and phenolic compounds, respectively ( Bergmüller et al., 2003 ; Diallinas and Kanellis, 1994 ; Gatzek et al., 2002 ), was determined. The
Amy Simonne, Eric Simonne, Ronald Eitenmiller and Christine Harris Coker
Lettuce (Lactuca sativa) production historically has been limited in the southeastern United States because of the risk of early bolting and unacceptable bitterness. Small-scale vegetable growers may be able to include lettuce in their production through selection of bolt tolerant and nonbitter varieties. The objectives of this research were to evaluate earliness, bitterness, vitamin E, ascorbic acid, folate, β-carotene, and lutein content in 17 lettuce varieties. Significant difference were found among varieties for days to harvest (DTH) (47 DTH for `Epic' to 37 DTH for `Big Curly'). Observed DTH in this study was consistently 7 to 10 days less than commercial descriptions of the lettuce varieties, due to the use of transplants. Only `Slobolt' and `Greengo' bolted before reaching marketable size. Panelists found that the bitterness was acceptable for most varieties, but not for `Nancy,' `Big Curly,' and `Slobolt'. Significant differences among varieties were also found in vitamin E, ascorbic acid, folate, β-carotene, and lutein. `Redprize' and `Nevada' were the best varieties overall, while `Salinas 88 Supreme,' `Epic,' `Legacy,' `Big Curly,' `Slobolt,' and `Greengo' were unacceptable.
Carrots contribute ≈14% of the total Vitamin A to the human diet in the United States due to the presence of the provitamin A carotenoids α- and β-carotene. We have described a recessive gene (rp) that inhibits carotenoid biosynthesis in carrot by 93%, resulting in whitish-yellow roots. The rp mutation is also associated with relatively high levels of a tocopherol (Vitamin E, 0.61±0.15 mg α-tocopherol/100 g FW). Vitamin E is a powerful antioxidant that must be obtained from the diet. The biosynthesis of a tocopherol in carrot has not been studied in any detail; however, the rp gene may provide clues as to its mechanism. The production of carotenoids and tocopherols is biosynthetically linked by their common precursor, geranylgeranyl diphosphate (GGDP). GGDP is converted into phytoene by phytoene desaturase to produce carotenoids and combined with homogentisic acid to produce tocopherols. Carotenoid and tocopherol profiles for various carrot genotypes are presented alongside a model describing the potential relationship between root carotenoids and tocopherols in carrot. The presence of significant amounts of tocopherols in carrot could significantly raise the nutritional profile of this vegetable.