Refine
Year of publication
Document Type
- Article (10)
- Postprint (3)
- Doctoral Thesis (2)
Language
- English (15)
Is part of the Bibliography
- yes (15) (remove)
Keywords
- carotenoids (15) (remove)
It is proposed that xanthophylls, and carotenoids in general, may assist in energy transfer from the chlorophyll Soret band to the Q band. Ground-state (1A(g)) and excited-state (1B(u)) optimizations of violaxanthin (Vx) and zeaxanthin (Zx) are performed in an environment mimicking the light-harvesting complex II (LHCII), including the closest chlorophyll b molecule (Chl). Time-dependent density functional theory (TD-DFT, CAM-B3LYP functional) is used in combination with a semi-empirical description to obtain the excited-state geometries, supported by additional DFT/multireference configuration interaction calculations, with and without point charges representing LHCII. In the ground state, Vx and Zx show similar properties. At the 1B(u) minimum, the energy of the Zx 1Bu state is below the Chl Q band, in contrast to Vx. Both Vx and Zx may act as acceptors of Soret-state energy; transfer to the Q band seems to be favored for Vx. These findings suggest that carotenoids may generally mediate Soret-to-Q energy flow in LHCII.
With the many challenges facing the agricultural system, such as water scarcity, loss of arable land due to climate change, population growth, urbanization or trade disruptions, new agri-food systems are needed to ensure food security in the future. In addition, healthy diets are needed to combat non-communicable diseases. Therefore, plant-based diets rich in health-promoting plant secondary metabolites are desirable. A saline indoor farming system is representing a sustainable and resilient new agrifood system and can preserve valuable fresh water. Since indoor farming relies on artificial lighting, assessment of lighting conditions is essential. In this thesis, the cultivation of halophytes in a saline indoor farming system was evaluated and the influence of cultivation conditions were assessed in favor of improving the nutritional quality of halophytes for human consumption. Therefore, five selected edible halophyte species (Brassica oleracea var. palmifolia, Cochlearia officinalis, Atriplex hortensis, Chenopodium quinoa, and Salicornia europaea) were cultivated in saline indoor farming. The halophyte species were selected for to their salt tolerance levels and mechanisms. First, the suitability of halophytes for saline indoor farming and the influence of salinity on their nutritional properties, e.g. plant secondary metabolites and minerals, were investigated. Changes in plant performance and nutritional properties were observed as a function of salinity. The response to salinity was found to be species-specific and related to the salt tolerance mechanism of the halophytes. At their optimal salinity levels, the halophytes showed improved carotenoid content. In addition, a negative correlation was found between the nitrate and chloride content of halophytes as a function of salinity. Since chloride and nitrate can be antinutrient compounds, depending on their content, monitoring is essential, especially in halophytes. Second, regional brine water was introduced as an alternative saline water resource in the saline indoor farming system. Brine water was shown to be feasible for saline indoor farming
of halophytes, as there was no adverse effect on growth or nutritional properties, e.g. carotenoids. Carotenoids were shown to be less affected by salt composition than by salt concentration. In addition, the interaction between the salinity and the light regime in indoor farming and greenhouse cultivation has been studied. There it was shown that interacting light regime and salinity alters the content of carotenoids and chlorophylls. Further, glucosinolate and nitrate content were also shown to be influenced by light regime. Finally, the influence of UVB light on halophytes was investigated using supplemental narrow-band UVB LEDs. It was shown that UVB light affects the growth, phenotype and metabolite profile of halophytes and that the UVB response is species specific. Furthermore, a modulation of carotenoid content in S. europaea could be achieved to enhance health-promoting properties and thus improve nutritional quality. This was shown to be dose-dependent and the underlying mechanisms of carotenoid accumulation were also investigated. Here it was revealed that carotenoid accumulation is related to oxidative stress.
In conclusion, this work demonstrated the potential of halophytes as alternative vegetables produced in a saline indoor farming system for future diets that could contribute to ensuring food security in the future. To improve the sustainability of the saline indoor farming system, LED lamps and regional brine water could be integrated into the system. Since the nutritional properties have been shown to be influenced by salt, light regime and UVB light, these abiotic stressors must be taken into account when considering halophytes as alternative vegetables for human nutrition.
Lutein and its isomer zeaxanthin have gained considerable interest as possible nutritional ingredient in the prevention of age-related macular degeneration (AMD) in humans. Egg yolk is a rich source of these carotenoids. As an oxidative sensitive component, antioxidants such as -tocopherol (T) might contribute to an improved accumulation in egg yolk. To test this, chickens were fed lutein esters (LE) with and without -tocopherol as an antioxidant. After depletion on a wheat-soya bean-based lutein-poor diet for 21days, laying hens (n=42) were equally divided into three groups and fed the following diets for 21days: control (basal diet), a LE group (40mg LE/kg feed) and LE+T group (40mg LE plus 100mg T/kg feed). Eggs and blood were collected periodically. Carotenoids and -tocopherol in yolk and blood plasma were determined by HPLC. Egg yolk was also analysed for total carotenoids using a one-step spectrophotometric method (iCheck(())). Lutein, zeaxanthin, -tocopherol and total carotenoids in egg yolk were highest after 14days of feeding and decreased slightly afterwards. At the end of the trial, eggs of LE+T group contained higher amount of lutein (13.72), zeaxanthin (0.65), -tocopherol (297.40) and total carotenoids (21.6) compared to the LE group (10.96, 0.55, 205.20 and 18.0mg/kg, respectively, p<0.05). Blood plasma values of LE+T group contain higher lutein (1.3), zeaxanthin (0.06) and tocopherol (20.1) compared to LE group (1.02, 0.04 and 14.90mg/l, respectively, p<0.05). In conclusion, dietary -tocopherol enhances bioavailability of lutein reflecting higher content in egg yolk and blood plasma. Improved bioavailability might be due to increased absorption of lutein in the presence of tocopherol and/or a greater stability of lutein/zeaxanthin due to the presence of -tocopherol as an antioxidant.
Effect of Solid Biological Waste Compost on the Metabolite Profile of Brassica rapa ssp chinensis
(2018)
Large quantities of biological waste are generated at various steps within the food production chain and a great utilization potential for this solid biological waste exists apart from the current main usage for the feedstuff sector. It remains unclear how the usage of biological waste as compost modulates plant metabolites. We investigated the effect of biological waste of the processing of coffee, aronia, and hop added to soil on the plant metabolite profile by means of liquid chromatography in pak choi sprouts. Here we demonstrate that the solid biological waste composts induced specific changes in the metabolite profiles and the changes are depending on the type of the organic residues and its concentration in soil. The targeted analysis of selected plant metabolites, associated with health beneficial properties of the Brassicaceae family, revealed increased concentrations of carotenoids (up to 3.2-fold) and decreased amounts of glucosinolates (up to 4.7-fold) as well as phenolic compounds (up to 1.5-fold).
Pak choi (Brassica rapa subsp. chinensis) is rich in secondary metabolites and contains numerous antioxidants, including flavonoids; hydroxycinnamic acids; carotenoids; chlorophylls; and glucosinolates, which can be hydrolyzed to epithionitriles, nitriles, or isothiocyanates. Here, we investigate the effect of reduced exposure to ultraviolet B (UVB) and UV (UVA and UVB) light at four different developmental stages of pak choi. We found that both the plant morphology and secondary metabolite profiles were affected by reduced exposure to UVB and UV, depending on the plant’s developmental stage. In detail, mature 15- and 30-leaf plants had higher concentrations of flavonoids, hydroxycinnamic acids, carotenoids, and chlorophylls, whereas sprouts contained high concentrations of glucosinolates and their hydrolysis products. Dry weights and leaf areas increased as a result of reduced UVB and low UV. For the flavonoids and hydroxycinnamic acids in 30-leaf plants, less complex compounds were favored, for example, sinapic acid acylated kaempferol triglycoside instead of the corresponding tetraglycoside. Moreover, also in 30-leaf plants, zeaxanthin, a carotenoid linked to protection during photosynthesis, was increased under low UV conditions. Interestingly, most glucosinolates were not affected by reduced UVB and low UV conditions. However, this study underlines the importance of 4-(methylsulfinyl)butyl glucosinolate in response to UVA and UVB exposure. Further, reduced UVB and low UV conditions resulted in higher concentrations of glucosinolate-derived nitriles. In conclusion, exposure to low doses of UVB and UV from the early to late developmental stages did not result in overall lower concentrations of plant secondary metabolites.
The spider mite Tetranychus urticae Koch and the aphid Myzus persicae (Sulzer) both infest a number of economically significant crops, including tomato (Solanurn lycopersicum). Although used for decades to control pests, the impact of green lacewing larvae Chrysoperla carnea (Stephens) on plant biochemistry was not investigated. Here, we used profiling methods and targeted analyses to explore the impact of the predator and herbivore(s)-predator interactions on tomato biochemistry. Each pest and pest -predator combination induced a characteristic metabolite signature in the leaf and the fruit thus, the plant exhibited a systemic response. The treatments had a stronger impact on non-volatile metabolites including abscisic acid and amino acids in the leaves in comparison with the fruits. In contrast, the various biotic factors had a greater impact on the carotenoids in the fruits. We identified volatiles such as myrcene and alpha-terpinene which were induced by pest -predator interactions but not by single species, and we demonstrated the involvement of the phytohormone abscisic acid in tritrophic interactions for the first time. More importantly, C. carnea larvae alone impacted the plant metabolome, but the predator did not appear to elicit particular defense pathways on its own. Since the presence of both C. carnea larvae and pest individuals elicited volatiles which were shown to contribute to plant defense, C. carnea larvae could therefore contribute to the reduction of pest infestation, not only by its preying activity, but also by priming responses to generalist herbivores such as T urticae and M. persicae. On the other hand, the use of C. carnea larvae alone did not impact carotenoids thus, was not prejudicial to the fruit quality. The present piece of research highlights the specific impact of predator and tritrophic interactions with green lacewing larvae, spider mites, and aphids on different components of the tomato primary and secondary metabolism for the first time, and provides cues for further in-depth studies aiming to integrate entomological approaches and plant biochemistry.
The spider mite Tetranychus urticae Koch and the aphid Myzus persicae (Sulzer) both infest a number of economically significant crops, including tomato (Solanurn lycopersicum). Although used for decades to control pests, the impact of green lacewing larvae Chrysoperla carnea (Stephens) on plant biochemistry was not investigated. Here, we used profiling methods and targeted analyses to explore the impact of the predator and herbivore(s)-predator interactions on tomato biochemistry. Each pest and pest -predator combination induced a characteristic metabolite signature in the leaf and the fruit thus, the plant exhibited a systemic response. The treatments had a stronger impact on non-volatile metabolites including abscisic acid and amino acids in the leaves in comparison with the fruits. In contrast, the various biotic factors had a greater impact on the carotenoids in the fruits. We identified volatiles such as myrcene and alpha-terpinene which were induced by pest -predator interactions but not by single species, and we demonstrated the involvement of the phytohormone abscisic acid in tritrophic interactions for the first time. More importantly, C. carnea larvae alone impacted the plant metabolome, but the predator did not appear to elicit particular defense pathways on its own. Since the presence of both C. carnea larvae and pest individuals elicited volatiles which were shown to contribute to plant defense, C. carnea larvae could therefore contribute to the reduction of pest infestation, not only by its preying activity, but also by priming responses to generalist herbivores such as T urticae and M. persicae. On the other hand, the use of C. carnea larvae alone did not impact carotenoids thus, was not prejudicial to the fruit quality. The present piece of research highlights the specific impact of predator and tritrophic interactions with green lacewing larvae, spider mites, and aphids on different components of the tomato primary and secondary metabolism for the first time, and provides cues for further in-depth studies aiming to integrate entomological approaches and plant biochemistry.
Young kale and pea leaves are rich in secondary plant metabolites (SPMs) whose profile can be affected by ultraviolet B (UVB) radiation. Carotenoids and flavonoids in kale and pea exposed to narrow-banded UVB, produced by innovative light-emitting diodes (LEDs), and subsequently used for breadmaking were investigated for the first time, thus combining two important strategies to increase the SPMs intake. Breads were also fortified with protein-rich lentil flour. Antioxidant activity in the ‘vegetable breads’ indicated health-promoting effects. Lentil flour increased the antioxidant activity in all of the ‘vegetable breads’. While carotenoids and chlorophylls showed a minor response to UVB treatment, kaempferol glycosides decreased in favor of increasing quercetin glycosides, especially in kale. Additionally, breadmaking caused major decreases in carotenoids and a conversion of chlorophyll to bioactive degradation products. In ‘kale breads’ and ‘pea breads’, 20% and 84% of flavonoid glycosides were recovered. Thus, kale and pea leaves seem to be suitable natural ingredients for producing innovative Functional Foods.
Carotenoids are lipid-soluble pigments and important for a variety of physiological functions. They are major dietary vitamin A precursors and act as lipophilic antioxidants in a variety of tissues and are associated with important health benefits in humans and animals. All animals must acquire carotenoids from their diet, but to our knowledge, there are no studies investigating the intestinal carotenoid absorption and their blood concentrations in New World camelids. The present study aimed to assess the serum concentrations of selected carotenoids in llamas (n=13) and alpacas (n=27). Serum carotenoids as well as retinol (vitamin A) and -tocopherol (vitamin E) were determined by high-performance liquid chromatography coupled with mass spectrometry and these were unable to detect any carotenoids (- and -carotene, - and -cryptoxanthin, lutein, zeaxanthin, lycopene) in the samples. The concentrations of retinol in alpacas (2.89 +/- 1.13mol/l; mean +/- SD) were higher (p=0.024) than those found in llamas (2.05 +/- 0.87mol/l); however, the concentrations of -tocopherol were not significantly (p=0.166) different (llamas: 3.98 +/- 1.83mol/l; alpacas: 4.95 +/- 2.14mol/l). The results show that both llamas and alpacas are not able to absorb intact carotenoids, but efficiently convert provitamin A carotenoids to retinol.
Regular consumption of fruits and vegetables, which is related to high plasma levels of lipid-soluble micro-nutrients such as carotenoids and tocopherols, is linked to lower incidences of various age-related diseases. Differences in lipid-soluble micronutrient blood concentrations seem to be associated with age. Our retrospective analysis included men and women aged 22-37 and 60-85 years from the Berlin Aging Study II. Participants with simultaneously available plasma samples and dietary data were included (n = 1973). Differences between young and old groups were found for plasma lycopene, alpha-carotene, alpha-tocopherol, beta-cryptoxanthin (only in women), and gamma-tocopherol (only in men). beta-Carotene, retinol and lutein/zeaxanthin did not differ between young and old participants regardless of the sex. We found significant associations for lycopene, alpha-carotene (both inverse), alpha-tocopherol, gamma-tocopherol, and beta-carotene (all positive) with age. Adjusting for BMI, smoking status, season, cholesterol and dietary intake confirmed these associations, except for beta-carotene. These micronutrients are important antioxidants and associated with lower incidence of age-related diseases, therefore it is important to understand the underlying mechanisms in order to implement dietary strategies for the prevention of age-related diseases. To explain the lower lycopene and alpha-carotene concentration in older subjects, bioavailability studies in older participants are necessary.