Carrots have favorable nutritional characteristics, containing antioxidant vitamins, carotenoids, and other bioactive micronutrients (Metzger and Barnes, 2009; Nicolle et al., 2004). Carrots are suitable basic material for the production of functional food products (Arscott and Tanumihardjo, 2010), mainly as a result of the high level of biologically active carotenoids. In orange carrots, β-carotene and α-carotene have been found dominant in different organic solvent extracts of such a crop (Baranski et al., 2012; Nicolle et al., 2004; Surles et al., 2004). In European countries, carrots contribute to 40% to 60% of β-carotene and from 80% to 90% of α-carotene intake from vegetables (O’Neill et al., 2001).
Beside the genetic factors, environment can substantially affect the carotenoid content in carrots. Warmer conditions usually result in a higher content of carotenes (Kaack et al., 2001; Tsukakoshi et al., 2009). Fikselová et al. (2010) found that irrigation and a larger amount of rainfall decreased β-carotene content of carrot.
Vegetables are not the main dietary sources of tocopherols; the richest sources are cereals and plant originated fats and oils (DellaPenna and Méne-Safranné, 2011). However, carotenoids and tocopherols share a common precursor [geranylgeranyl pyrophosphate (GGPP)] and because ofs being antioxidants, both have important roles within the human diet (DellaPenna and Méne-Safranné, 2011). Thus, from a nutritional point of view, the concentration and the composition of these two groups of phytonutrients are of specific importance. Genotypic effect on tocopherol content in carrot and on the relationship between carotenes and tocopherols has been investigated (Koch and Goldman, 2005; Nicolle et al., 2004) and parallel accumulation of these phytonutrients was found. We have hypothesized that water shortage, as a stress factor, may alter these correlations and the composition of carotenoids and tocopherols.
The objective of the present study was to investigate the effects of irrigation, compared with a rain-fed control, on the content and composition of carotenoids and tocopherols and on the relationship between them in an orange-colored carrot cultivar in 2 years with considerably different precipitation conditions.
Arscott, S.A. & Tanumihardjo, S.A. 2010 Carrots of many colors provide basic nutrition and bioavailable phytochemicals acting as a functional food Comprehensive Rev. Food Sci. Food Safety 9 223 239
Baranski, R., Allender, C. & Klimek-Chodacka, M. 2012 Towards better tasting and more nutritious carrots: Carotenoid and sugar content variation in carrot genetic resources Food Res. Intl. 47 182 187
Daood, H.G., Bencser, G., Palotás, G., Pék, Z., Sidikov, A. & Helyes, L. (in press) HPLC analysis of carotenoids from tomatoes using cross-linked C18 column and MS detection J. Chromatogr. Sci. doi: 10.1093/chromsci/bmt139
Dutta, D., Chaudhuri, U.R. & Chakraborty, R. 2005 Structure, health benefits, antioxidant property and processing and storage of carotenoids Afr. J. Biotechnol. 4 1510 1520
Fikselová, M., Mareĉek, J. & Mellen, M. 2010 Carotenes content in carrot roots (Daucus carota L.) as affected by cultivation and storage Veg. Crops Res. Bul. 73 47 54
Kaack, K.V., Nielsen, M., Christensen, L.P. & Thorup-Kristensen, K. 2001 Nutritionally important chemical constituents and yield of carrot roots (Daucus carota L.) grown organically using ten levels of green manure Acta Agriculturae Scandinavica, Section B-Soil and Plant Sci. 51 125 136
Koch, T.C. & Goldman, I.L. 2005 Relationship of carotenoids and tocopherols in a sample of carrot root-color accessions and carrot germplasm carrying Rp and rp alleles J. Agr. Food Chem. 53 325 331
Leskovar, D.I., Crosby, K. & Jifon, J.L. 2009 Impact of agronomic practices on phytochemicals and quality of vegetable crops Acta Hort. 841 317 322
Metzger, B.T. & Barnes, D.M. 2009 Polyacetylene diversity and bioactivity in orange market and locally grown colored carrots (Daucus carota L.) J. Agr. Food Chem. 57 11134 11139
Nicolle, C., Simon, G., Rock, E., Amouroux, P. & Rémésy, C. 2004 Genetic variability influences carotenoid, vitamin, phenolic, and mineral content of white, yellow, purple, orange and dark-orange carrot cultivars J. Amer. Soc. Hort. Sci. 129 523 529
O'Neill, M.E., Carroll, Y., Corridan, B., Olmedilla, B., Granado, F., Blanco, I., Van den Berg, H., Hininger, I., Rousell, A.M., Chopra, M., Southon, S. & Thurnham, D.I. 2001 A European carotenoid database to assess carotenoid intakes and its use in a five-country comparative study Brit. J. Nutr. 85 499 507
Surles, R.L., Weng, N., Simon, P.W. & Tanumihardjo, S.A. 2004 Carotenoid profiles and consumer sensory evaluation of specialty carrots (Daucus carota L.) of various colors J. Agr. Food Chem. 52 3417 3421
Tsukakoshi, Y., Naito, S., Ishida, N. & Yasui, A. 2009 Variation in moisture, total sugar, and carotene content of Japanese carrots: Use in sample size determination J. Food Compost. Anal. 22 373 380
U.S. Dept. Agr., Agr. Res. Serv 2011 National nutrient database for standard reference. Release 26. 7 Dec. 2011. <ndb.nal.usda.gov> <ndb.nal.usda.gov/ndb/foods/show/2949?fg=&man=&lfacet=&count=&max=&sort=&qlookup=&offset=&format=Full&new=&measureby=>