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Mark G. Lefsrud, Dean A. Kopsell, Robert M. Augé and A.J. Both

Consumption of fruit and vegetable crops rich in lutein and β-carotene carotenoids is associated with reduced risk of cancers and aging eye diseases. Kale (Brassica oleracea L. var. acephala D.C.) ranks highest for lutein concentrations and is an excellent source of dietary carotenoids. Kale plants were grown under varied photoperiods to determine changes in the accumulation of fresh and dry biomass, chlorophyll a and b, and lutein and β-carotene carotenoids. The plants were cultured in a controlled environment using nutrient solutions under photoperiod treatments of 6, 12, 16, or 24 hours (continuous). Fresh and dry mass production increased linearly as photoperiod increased, reaching a maximum under the 24-hour photoperiod. Maximum accumulation of lutein, β-carotene, and chlorophyll b occurred under the 24-h photoperiod at 13.5, 10.4, and 58.6 mg/100 g fresh mass, respectively. However, maximum chlorophyll a (235.1 mg/100 g fresh mass) occurred under the 12-hour photoperiod. When β-carotene and lutein were measured on a dry mass basis, the maximum accumulation was shifted to the 16-hour photoperiod. An increase in photoperiod resulted in increased pigment accumulation, but maximum concentrations of pigments were not correlated with maximum biomass production.

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Vincent Martineau, Mark Lefsrud, Most Tahera Naznin and Dean A. Kopsell

; Koski et al., 1951 ; Ogawa et al., 1973 ; Virgin, 1993 ), β-carotene biosynthesis ( Ogawa et al., 1973 ), and decreases in chlorophyll b under ultraviolet B light ( Taiz and Zeiger, 1998 ). Research has been performed to test the impact of light from

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Mark G. Lefsrud, Dean A. Kopsell, David E. Kopsell and Joanne Curran-Celentano

Crop plants are adversely affected by a variety of environmental factors, with air temperature being one of the most influential. Plants have developed a number of methods in the adaptation to air temperature variations. However, there is limited research to determine what impact air temperature has on the production of secondary plant compounds, such as carotenoid pigments. Kale (Brassica oleracea L.) and spinach (Spinacia oleracea L.) have high concentrations of lutein and β-carotene carotenoids. The objectives of this study were to determine the effects of different growing air temperatures on plant biomass production and the accumulation of elemental nutrients, lutein, β-carotene, and chlorophyll pigments in the leaves of kale and spinach. Plants were grown in nutrient solutions in growth chambers at air temperatures of 15, 20, 25, and 30 °C for `Winterbor' kale and 10, 15, 20, and 25 °C for `Melody' spinach. Maximum tissue lutein and β-carotene concentration occurred at 30 °C for kale and 10 °C for spinach. Highest carotenoid accumulations were 16.1 and 11.2 mg/100 g fresh mass for lutein and 13.0 and 10.9 mg/100 g fresh mass for β-carotene for the kale and spinach, respectively. Lutein and β-carotene concentration increased linearly with increasing air temperatures for kale, but the same pigments showed a linear decrease in concentration for increasing air temperatures for spinach. Quantifying the effects of air temperature on carotenoid accumulation in kale and spinach, expressed on a fresh mass basis, is important for growers producing these crops for fresh markets.

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Simone Fanasca, Giuseppe Colla, Youssef Rouphael, Francesco Saccardo, Giuseppe Maiani, Eugenia Venneria and Elena Azzini

A greenhouse experiment was carried out to determine the effect of cationic proportions (K, Ca, Mg) in the nutrient solution on carotenoids and α-tocopherol content at green–orange, orange, red, and intense-red ripening stages using a high-pigment tomato (Lycopersicon esculentum Mill.) cultivar hp (`Lunarossa') and a standard cultivar (`Corfù') grown in a soilless culture. The highest lycopene concentration was observed in the `hp' cultivar at the red and intense-red ripening stages (3.0 mg/100 g fresh weight and 3.2 mg/100 g fresh weight respectively). In both cultivars, the concentration of β-carotene increased during the ripening stages, reaching the highest value (0.6 mg/100 g fresh weight) at the intense-red stage. The hp cultivar has guaranteed higher lycopene (average, 2.0 mg/100 g fresh weight vs. 1.7 mg/100 g fresh weight) and α-tocopherol contents (average, 1.2 mg/100 g fresh weight vs. 0.9 mg/100 g fresh weight) than those of the standard. In both cultivars, a high proportion of K in the nutrient solution increased antioxidant concentration β-carotene and especially lycopene) during the red and intense-red ripening stages, followed by Mg. The lowest values were recorded for the Ca treatment. Lastly, a positive correlation was recorded between fruit tissue K and lycopene content, whereas a negative correlation was observed between fruit tissue Ca and lycopene content.

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Gene E. Lester, John L. Jifon and D. J. Makus

Netted muskmelon [Cucumis melo L. (Reticulatus Group)] fruit quality (ascorbic acid, β-carotene, total free sugars, and soluble solids concentration (SSC)) is directly related to plant potassium (K) concentration during fruit growth and maturation. During reproductive development, soil K fertilization alone is often inadequate due to poor root uptake and competitive uptake inhibition from calcium and magnesium. Foliar applications of glycine-complexed K during muskmelon fruit development has been shown to improve fruit quality, however, the influence of organic-complexed K vs. an inorganic salt form has not been determined. This glasshouse study investigated the effects of two K sources: a glycine-complexed K (potassium metalosate, KM) and potassium chloride (KCl) (both containing 800 mg K/L) with or without a non-ionic surfactant (Silwet L-77) on melon quality. Orange-flesh muskmelon `Cruiser' was grown in a glasshouse and fertilized throughout the study with soil-applied N–P–K fertilizer. Starting at 3 to 5 d after fruit set, and up to 3 to 5 d before fruit maturity at full slip, entire plants were sprayed weekly, including the fruit, with KM or KCl with or without a surfactant. Fruit from plants receiving supplemental foliar K had significantly higher K concentrations in the edible middle mesocarp fruit tissue compared to control untreated fruit. Fruit from treated plants were also firmer, both externally and internally, than those from non-treated control plants. Increased fruit tissue firmness was accompanied by higher tissue pressure potentials of K treated plants vs. control. In general, K treated fruit had significantly higher SSC, total sugars, total ascorbic acid, and β-carotene than control fruit. Fall-grown fruit generally had higher SSC, total sugars, total ascorbic acid and β-carotene concentrations than spring-grown fruit regardless of K treatment. The effects of surfactant were not consistent but in general, addition of a surfactant tended to affect higher SSC and β-carotene concentrations.

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Joshua R. Hyman, Jessica Gaus and Majid R. Foolad

Lycopene is the red pigment and a major carotenoid in tomato (Lycopersicon esculentum Mill.) fruit. It is a potent natural antioxidant, and the focus of many tomato genetics and breeding programs. Crop improvement for increased fruit lycopene content requires a rapid and accurate method of lycopene quantification. Among the various available techniques, high-performance liquid chromatography (HPLC) can be accurate, however, it is laborious and requires skilled labor and the use of highly toxic solvents. Similarly, spectrophotometric methods, although easier than HPLC, also require time-consuming extractions and may not be as accurate as HPLC, as they often overestimate fruit lycopene content. Colorimetric estimation of fruit lycopene using chromaticity values has been proposed as an alternative rapid method. Previous studies that examined the utility of this technique, however, were confined to the evaluation of only one or few cultivars and, therefore, lacked broad applicability. The purpose of the present study was to examine the utility of chromaticity values for estimating lycopene and β-carotene contents in tomato across diverse genetic backgrounds. Measurements of the chromaticity values (L*, a*, b*, C*, h*) were taken on whole fruit and purée of 24 tomato genotypes and were compared with HPLC measurements of fruit lycopene and β-carotene. Examination of different regression models indicated that a model based on the transformed value a*4 from purée measurements explained up to 94.5% of the total variation in fruit lycopene content as measured by HPLC. When this model was applied to a second set of fruit harvested at a later date from the same 24 genotypes, it explained more than 90% of the total variation in lycopene, suggesting its reliability. The best estimation for β-carotene content was obtained by using the b* chromaticity value from whole fruit measurements or the transformed a*2 value from purée measurements. Neither model, however, could explain more than 55% of the variation in β-carotene content, suggesting that chromaticity values may not be appropriate for estimating tomato β-carotene content. The overall results indicated that fruit lycopene content could be measured simply and rather accurately across a wide range of tomato genotypes using chromaticity values taken on fruit purée.

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Attila Ombódi, Hussein Gehad Daood and Lajos Helyes

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

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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.

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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.

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Dean A. Kopsell, David E. Kopsell and Joanne Curran-Celentano

Sweet basil (Ocimum basilicum L.) is a popular culinary herbal crop grown for fresh or dry leaf, essential oil, and seed markets. Recently, basil was shown to rank highest among spices and herbal crops for xanthophyll carotenoids, which are associated with decreased risks of cancer and age-related eye diseases. The research goal for the current study was to characterize the concentrations of nutritionally important carotenoid pigments in popular varieties of basil. Eight cultivars of sweet basil (`Genovese', `Italian Large Leaf', `Nufar', `Red Rubin', `Osmin Purple', `Spicy Bush', `Cinnamon', and `Sweet Thai') were grown in both field and greenhouse environments and evaluated for plant pigments using HPLC methodology. Environmental and cultivar differences were observed for all of the pigments analyzed. `Sweet Thai' accumulated the highest concentrations of lutein, zeaxanthin, and β-carotene carotenoids in the field, while `Osmin Purple' accumulated the highest carotenoid concentrations in the greenhouse. Comparing the two environments, cultivar levels for carotenoid and chlorophyll pigments were higher in the field environment when expressed on both a fresh and dry weight basis. Exceptions were found only for the purple leaf basils (`Osmin Purple' and `Red Rubin'). Positive correlations existed between carotenoid and chlorophyll pigments in both environments. This study demonstrates sweet basil accumulates high levels of nutritionally important carotenoids in both field and greenhouse environments.