Fresh leaves of 6 sweetpotato (Ipomoea batatas [L.] Lam.) genotypes, `Beauregard', `Bienville', L99–35, L00–8, L01–145, and L01–29, were characterized for lutein. Lutein is a carotenoid capable of delaying blindness-related macular degeneration. The content of lutein in sweetpotato ranged from 0.38 to 0.58 mg·g–1 fresh weight. Beta-carotene separated from lutein on high-pressure liquid chromatograms and when spiked in pure lutein extract did not interfere with lutein separation. High-resolution electro-spray ionization mass spectrometric analysis was used to confirm the presence of lutein in sweetpotato leaves. Stems were also characterized and found not to contain lutein. Our results showed that sweetpotato leaves are an excellent source of dietary lutein and surpass levels found in leafy crucifers. Leaves of sweetpotato and a related species are human food in some countries and may be a major source of lutein for commercial purposes.
Evdokia Menelaou, Armen Kachatryan, Jack N. Losso, Michael Cavalier, and Don La Bonte
Michael Cavalier, Armen Kachatryan, Evodokia Menelaou, Jack Losso, and Don LaBonte
Fresh leaves of six sweetpotato [Ipomoea batatas (L.) Lam.] genotypes, `Beauregard', `Bienville', L 99-35, L 00-8, L 01-145, and L 01-29 were characterized for lutein. Lutein is a carotenoid capable of delaying blindness-related macular degeneration. The content of lutein in sweetpotato ranged from 0.38 to 0.58 mg·g-1 fresh weight. Beta-carotene separated from lutein on HPLC chromatograms, and, when spiked in pure lutein extract, did not interfere with lutein separation. Stems were also characterized and found not to contain lutein. Our results showed that sweetpotato leaves are an excellent source of dietary lutein and surpass levels found in leafy crucifers. Leaves of sweetpotato and a related species are used as human food in some countries and could be a source of extracted lutein for commercial purposes.
Mark G. Lefsrud and Dean A. Kopsell
Chlorophyll and carotenoid pigments were measured with high-performance liquid chromatography (HPLC) during leaf development in kale (Brassicaoleracea L. var. acephala D.C). Lutein and β-carotene are two plant-derived carotenoids that possess important human health properties. Diets high in these carotenoids are associated with a reduced risk of cancer, cataracts, and age-related macular degeneration. Kale plants were growth-chamber grown in nutrient solution culture at 20 °C under 500 μmol·m-2·s-1 of irradiance. Pigments were measured in young (<1 week), immature (1-2 weeks), mature (2-3 weeks), fully developed (3-4 weeks) and senescing (>4 weeks) leaves. Significant differences were measured for all four pigments during leaf development. Accumulation of the pigments followed a quadratic trend, with maximum accumulation occurring between the first and third week of leaf age. The highest concentrations of lutein were recorded in 1- to 2-week-old leaves at 15.1 mg per 100 g fresh weight. The remaining pigments reached maximum levels at 2-3 weeks, with β-carotene at 11.6 mg per 100 g, chlorophyll a at 251.4 mg per 100 g, and chlorophyll b at 56.9 mg per 100 g fresh weight. Identifying changes in carotenoid and chlorophyll accumulation over developmental stages in leaf tissues is applicable to “baby” leafy greens and traditional production practices for fresh markets.
T.E. Morelock, J.A. Kirkpatrick, D.R. Motes, J.C. Correll, and F.J. Daniello
The current national trends in nutrition have resulted in a very high interest in the benefits of proper diet. It is very apparent that adding foods high in antioxidants to the human diet can have drastic affects on human health by reducing the risk of cancer, cardiovascular and pulmonary disease, as well as age-related degenerative diseases. It is well-known and well-documented that spinach is one of the very best vegetables in antioxidant potential. It is high in beta-carotene (provitamin A) and is also very high in lutein (a carotenoid that is a strong antioxidant but with no vitamin A activity). Lutein has also been documented to have the potential to significantly reduce macular degeneration in humans when added to the diet on a regular basis. With these health benefits in mind the Univ. of Arkansas is releasing the spinach breeding line that has been tested as 88-310. It is a slow-growing semi-savoy that exhibits excellent color and has a moderate level of white rust resistance. It has excellent plant type, producing a very attractive compact rosette plant that is very desirable for root cut whole plants or for various types of clipped spinach. It is best-suited to both fall and overwinter production in Arkansas and for winter production in the Texas wintergarden. Seed for tests can be obtained by contacting T.E. Morelock, Dept. of Horticulture, Univ. of Arkansas, Fayetteville, AR 72701.
J.A. Kirkpatrick, T.E. Morelock, L.R. Howard, and F.J. Dainello
Fresh-market spinach production has risen in the United States in the past few years as well as total value of the crop. Increased crop value may be attributed to more “value added” spinach products being produced and marketed. Public awareness of nutrition is rising due to more information being distributed concerning cancer prevention, antioxidants, and neutraceuticals. Spinach is high in the carotenoids beta-carotene and lutein, a known antioxidant for the prevention of age-related macular degeneration (AMD). It is also high in vitamins A, C, E, and folate, fiber, and the mineral iron. In this respect, spinach producers have an advantage over growers of salad vegetables such as lettuce. While this is an advantage, more innovative “value added” methods of marketing this product to the consumer are needed. A dark-green, semi-savoy spinach type developed at the Univ. of Arkansas was studied to determine shelf-life and storage capabilities of root cut plants in transparent clamshell containers. Plants were held at temperatures ranging from 1 to 6 °C. Leaf turgidity and visual characteristics were rated on a 1 to 5 scale. Acceptable characteristics and shelf-life of spinach stored in clamshell containers were seen up to 14 to 21 days when plants were stored at or near 1 °C. These results indicate that spinach packaged in transparent clamshell containers will maintain an acceptable shelf-life and could be beneficial to fresh market spinach producers.
Kevin M. Crosby, Daniel I. Leskovar, and Kil Sun Yoo
At the Vegetable and Fruit Improvement Center, plant breeding has produced pepper lines with enhanced beneficial phytochemical levels. TAM `Dulcito' is a new jalapeño cultivar with no detectable levels of capsaicin, but increased levels of lutein. In greenhouse cultivation, it contained 122 ppm of this important human health-related compound, which aids in prevention of macular degeneration. This is a significant improvement over popular cultivars, such as `Grande', which contained 25 ppm or less. In addition to improved lutein levels, `Dulcito' also possesses resistance to three important potyviruses: TEV, PepMoV, and PVY. In field trials at Weslaco, Texas, `Dulcito' outyielded both TAM `Mild Jalapeño 2', and `Mitla'. This new cultivar produces a concentrated set of large, thick-fleshed fruit with few cuticular cracks. Because of its lack of pungency, it should be useful for the processing industry. TAM `Tropic Bell' is a medium-sized, blocky bell with enhanced levels of both ascorbic acid and lutein compared to other cultivars. Grown under greenhouse conditions, it contained 100 ppm lutein compared to 6 ppm in `Jupiter'. It also contained 660 ppm ascorbic acid at the green stage, compared to less than 100 ppm for three commercial bell cultivars tested. `Tropic Bell' produced yields equal to both `Valiant' and `Summer Sweet' commercial hybrids at Weslaco. Fruit of `Tropic Bell' were slightly smaller than the hybrid cultivars. TAM `Tropic Bell' possesses resistance to the same three potyviruses as `Dulcito' and demonstrated excellent tolerance to Phytophthora capsici in a controlled inoculation. These two new cultivars will be useful for production in locations with high potyvirus pressure or as specialty market items for health-conscious consumers.
Khalid Ibrahim and John Juvik
Vegetables are a rich source of dietary carotenoids and tocopherols, powerful antioxidants that have the capacity to protect cells against oxidative damage caused by free radical reactions. There is evidence for a negative correlation between the incidence of certain types of cancer, age-related macular degeneration, cataract development, and cardiovascular disease with increased carotenoid and tocopherol intake. Development of elite vegetable germplasm with enhanced levels of these phytochemicals will potentially promote health among the consuming public. To assess the feasibility for genetic improvement in phytochemical content, it is necessary to partition the phenotypic variability into its component sources (genotype, environment, and genotype by environment interaction). To provide data for comparison and partition of phenotypic variation, 41 sweet corn and 13 broccoli genotypes were grown and harvested in one location for 3 years and analyzed for phytochemical content by HPLC. The most abundant form of carotenoids and tocopherols were lutein and gamma-tocopherol in sweet corn and beta-carotene and alpha-tocopherol in broccoli. Analysis of variance showed that, in sweet corn, the differences among genotypes described most of the phenotypic variation (76% for lutein, and 78% for gamma-tocopherol). Genotype by year interaction was a second significant factor, while variation affiliated with the year was found to be a minor component. In contrast, in broccoli, the three sources of variability contributed equally to describe the total phenotypic variation for beta-carotene and alpha-tocopherol. These results suggest that elite sweet corn and broccoli germplasm with improved carotenoid and tocopherol levels can be developed using conventional breeding protocols.
Wenhe Lu, Kathleen Haynes, Eugene Wiley, and Beverly Clevidence
The yellow pigment in potato (Solanum L. sp.) tuber flesh is caused by various carotenoids that may protect against cancer, cardiovascular disease, and macular eye degeneration. The objectives of this research were to 1) identify and quantify the carotenoids present in 11 diploid clones from a hybrid population of Solanum phureja ssp. phureja Juz. & Bukasov-S. stenotomum ssp. stenotomum Juz. & Bukasov and two tetraploid potato cultivars (the yellow-fleshed `Yukon Gold' and the white-fleshed `Superior'), and 2) determine the relationship between tuber yellow intensity and carotenoid content. Yellow intensity was measured by a colorimeter programmed to calculate a yellowness index, YI E-313. Carotenoid analyses were performed on an automated high-performance liquid chromatography system with software for integration and quantitation with detection at 450 nm using a diode array detector. Six major carotenoids were detected: neoxanthin, violaxanthin, lutein-5,6-epoxide, lutein, zeaxanthin, and an unknown carotenoid. Total carotenoid content in the yellow-fleshed diploid clones was 3 to 13 times higher than `Yukon Gold' and 4 to 22 times higher than `Superior'. Both total and individual carotenoid contents were positively correlated with tuber yellow intensity. There was an exponential relationship between total carotenoid content and tuber yellow intensity. This suggests that selecting for more intense yellow flesh will result in higher levels of carotenoids. These specific diploid clones were selected for this study because they produced at least five percent 2n pollen; they have the potential to make significant contributions to improving the nutritional status of tetraploid potatoes through 4x-2x hybridizations.
Ivette Guzman, Danise Coon, Krystal Vargas, and Paul W. Bosland
). For adults older than 65 years living in industrialized countries, age-related macular degeneration is the leading cause of blindness. Lutein is known to improve or even prevent age-related macular disease, which is the leading cause of blindness and
Mark G. Lefsrud, Dean A. Kopsell, and Carl E. Sams
energetic triplet state of the Chl molecule to prevent damage to the photosynthetic system ( Tracewell et al., 2001 ). In humans, dietary intake of foods rich in carotenoids is associated with reduced risk of lung cancer, cataracts, and age-related macular