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 DellaPenna, 2010). Tocochromanols result from the condensation of homogentisate and phytyl pyrophosphate derived from the shikimate pathway and the nonmevalonate 1-deoxy-d-xylulose-5-phosphate pathway, respectively (DellaPenna and Pogson, 2006). Vitamin E is an essential nutrient in the human diet, critical for membrane integrity and stability, and has a variety of health promoting properties (Hunter and Cahoon, 2007). Seeds, nuts, and oils are recognized as good sources of vitamin E and some orange and red vegetables and leafy greens have been noted to contain vitamin E. Murphy et al. (1990) found that vegetables were the second largest contributor, after fats and oils, to vitamin E intake in the adult U.S. diet, representing 15.1% of the total vitamin E contribution. Even though nuts and seeds are rich sources of vitamin E, they are consumed by fewer people and in smaller amounts than other vitamin E sources, and contribute ≈4-fold less to total vitamin E intake (Murphy et al., 1990).
Carrots (Daucus carota L. var. sativa), well known for high concentrations of provitamin A carotenoids, also contain vitamin E. Koch and Goldman (2005) and Luby et al. (2014) have reported several tocochromanols in carrot, including α-, β- and γ-tocopherol and α, β-, and γ-tocotrienol. Burns et al. (2003) and Koch and Goldman (2005) used reverse-phase HPLC equipped with an ultraviolet detector to quantify vitamin E levels in carrot roots. These studies reported values of 0.03–0.11 µg·g−1 of total α- and β- tocopherol on a fresh weight basis. Luby et al. (2014) used more sensitive and specific fluorescence detection during HPLC analysis, which was capable of measuring additional tocotrienols and tocopherols. Luby et al. (2014) measured an average of 0.12 µg·g−1 converted to a fresh weight basis of total tocochromanols in hybrid carrot roots. Ombodi et al. (2014), Metzger and Barnes (2009), and Nicolle et al. (2004) measured tocochromanols in carrot using various techniques. These three studies revealed levels of tocochromanols in carrot that were significantly higher than those reported by Burns et al. (2003), Koch and Goldman (2005), and Luby et al. (2014). The NNB contains values for vitamin E levels in fresh carrot and for some commercial food products that contain carrot. In this study, we evaluated tocochromanol levels in commercially available carrots and food products containing carrot to obtain a fuller picture of vitamin E levels in this vegetable, and compared our findings to published levels for vitamin E in carrot and to those in the NNB.
Anonymous2014Vitamin E National Institutes of Health. 18 Feb. 2014. <http://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/>
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USDA2014United States Department of Agriculture. USDA National Nutrient Database for Standard Reference Release 26. 18 Feb. 2014. <http://www.ars.usda.gov/ba/bhnrc/ndl>