Decrease In Carotenoid Content Research Articles

Characterization of Two Lycopene Beta-cyclases Reveal Their Essential Roles in Photoprotection in Nicotiana Tabacum

Carotenoids are essential isoprenoids with vital roles in photoprotection and antioxidative processes in photosynthetic organisms. Lycopene Beta-cyclase (β-LCY) is a key enzyme in carotenoid biosynthesis; however, the role of β-LCY in photoprotection is still unclear. In this study, we characterized two β-LCY genes in an allotetraploid tobacco cultivar K326, that are primarily expressed in leaves. Reduction of β-LCY expression by RNA interfercnce (RNAi) resulted in decreased carotenoid content, leaf variegation, impaired photosynthetic efficiency, and abnormal chloroplast morphology. β-LCY RNAi plants exhibited hypersensitivity to high light and lower non-photochemical quenching (NPQ) values under both normal and high light conditions. The stability of D1, a core subunit of photosystem II reaction center, was dramatically impaired β-LCY RNAi plants upon exposure to high light, suggesting severe photodamage of photosystem. Furthermore, reactive oxygen species (ROS) content was increased in β-LCY RNAi plants compared to WT plants under both normal and high light conditions. These results indicate that β-LCY is crucial for NPQ, D1 stability and ROS homeostasis, thus protecting photosystem from photooxidative damage. These findings contribute to our understanding on the function of plant β-LCY and its potential implications for plant growth, development, and photoprotection.

Improving the physiological properties and yield of safflower by combining organic and chemical nitrogen in different irrigation cut-off conditions

The purpose of this work was to investigate how different nutrition systems (N0: 0:0, N1: 100:0, N2: 75:25, N3: 50:50, N4: 25:75, and N5: 0:100 kg ha−1 nitrogen from urea and organic fertilizer sources respectively) affect the physiological characteristics and yield of safflower (Carthamus tinctorius L.) under different irrigation regimes. These irrigation regimes include complete irrigation (S0), irrigation cut-off at stem elongation (S1), flowering and pollination (S2), and grain filling (S3) stages. The S1 irrigation level led to a decrease in Fv/Fm (5 %), relative water content (RWC) of the leaf (17 %), leaf total chlorophyll (22 %), and soluble proteins of the leaf (21 %) an increase in electrolyte leakage (33 %), carotenoids (43 %), proline content (42 %) and soluble sugars of the leaf (39 %) compared with S0 irrigation level. The safflower leaf showed increased Fv/Fm, RWC, total chlorophyll, and soluble proteins when organic fertilizer was used alone or in combination with chemical fertilizers under irrigation cut-off conditions. Additionally, the use of organic fertilizer resulted in a decrease in carotenoid content, proline content, and soluble sugars of the safflower leaf. The highest biological yield was obtained with S0 irrigation level (21.62 t ha−1) and N3 integrated nutrition system (21.93 t ha−1), respectively. The N3 and N2 nutrition systems increased the grain yield by 3.34 t ha−1 and 3.56 t ha−1 in 2015 and 2016, respectively. The greatest negative effect on biological yield was observed when irrigation was cut-off during the vegetative stage, while the most detrimental impact on grain yield occurred when irrigation was ceased during the flowering and pollination stages. Overall, the results indicated that N2 and N3 nutrition systems while implementing irrigation cut-off at various growth stages reduced the negative impact of water deficiency on plants. This leads to decreased production costs for stress-resistant osmolytes and, consequently, improved grain yield and biological yield.

Effects of different light intensity on leaf color changes in a Chinese cabbage yellow cotyledon mutant.

Leaf color is one of the most important phenotypic features in horticultural crops and directly related to the contents of photosynthetic pigments. Most leaf color mutants are determined by the altered chlorophyll or carotenoid, which can be affected by light quality and intensity. Our previous study obtained a Chinese cabbage yellow cotyledon mutant that exhibited obvious yellow phenotypes in the cotyledons and the new leaves. However, the underlying mechanisms in the formation of yellow cotyledons and leaves remain unclear. In this study, the Chinese cabbage yellow cotyledon mutant 19YC-2 exhibited obvious difference in leaf color and abnormal chloroplast ultrastructure compared to the normal green cotyledon line 19GC-2. Remarkably, low-intensity light treatment caused turn-green leaves and a significant decrease in carotenoid content in 19YC-2. RNA-seq analysis revealed that the pathways of photosynthesis antenna proteins and carotenoid biosynthesis were significantly enriched during the process of leaf color changes, and many differentially expressed genes related to the two pathways were identified to respond to different light intensities. Remarkably, BrPDS and BrLCYE genes related to carotenoid biosynthesis showed significantly higher expression in 19YC-2 than that in 19GC-2, which was positively related to the higher carotenoid content in 19YC-2. In addition, several differentially expressed transcription factors were also identified and highly correlated to the changes in carotenoid content, suggesting that they may participate in the regulatory pathway of carotenoid biosynthesis. These findings provide insights into the molecular mechanisms of leaf color changes in yellow cotyledon mutant 19YC-2 of Chinese cabbage.

Molecular insights into a non-lethal yellow bud mutant in Ilex × ‘Nellie R. Stevens’

While the mechanisms behind the yellow phenotype have been widely investigated in model plant seedlings, research on leaf mutations in woody species has been restricted. The purpose of this research is to characterize a holly bud mutant of Ilex × ‘Nellie R. Stevens’ with a non-lethal yellow phenotype. Through cytological, physiological, metabolomic, and transcriptomic analyses, we identified remarkable differences between the mutant and its wild-type. The mutant exhibited abnormal chloroplasts, reduced chlorophyll levels, and elevated carotenoid/chlorophyll ratios. Metabolomic and transcriptomic analyses identified differentially expressed genes (DEGs) associated with chlorophyll and heme biosynthesis disruption, contributing to the chlorophyll-deficient phenotype. Moreover, genes associated with carotenoid metabolism were significantly down-regulated, linking to decreased carotenoid content and impacting photoprotection. Down-regulated DEGs in photosynthesis-related underscored the mutant's diminished photosynthetic activity. Additionally, the study identified 382 DEGs encoding putative transcription factors such as bHLHs, NACs, and GLKs. The study suggests an intricate interplay between chlorophyll, heme and carotenoid metabolism as major regulators of leaf mutation in I. × ‘Nellie R. Stevens.’ These insights contribute to the understanding of leaf color variation, enabling targeted strategies for developing desirable ornamental cultivars.

Characterization of Fusarium verticillioides Med1 LxxLL Motif Involved in Fumonisin Biosynthesis.

The Med1 transcriptional coactivator is a crucial component of the Mediator middle complex, which regulates the expression of specific genes involved in cell development, differentiation, reproduction, and homeostasis. The Med1 LxxLL motif, a five-amino-acid peptide sequence, is essential for Med1-mediated gene expression. Our previous study revealed that the disruption of the Med1 subunit leads to a significant increase in fumonisin B1 (FB1) production in the maize pathogen Fusarium verticillioides. However, our understanding of how Med1 regulates FB1 biosynthesis in F. verticillioides, particularly through the Med1 LxxLL motifs, remains limited. To characterize the role of LxxLL motifs, we generated a series of Med1 LxxLL deletion and amino acid substitution mutants. These mutants exhibited impaired mycelial growth and conidia germination while demonstrating enhanced conidia production and virulence. Similar to the Med1 deletion mutant, Med1 LxxLL motif mutants also exhibited increased FB1 biosynthesis in F. verticillioides. Proteomic profiling revealed that the Med1 LxxLL motif regulated the biosynthesis of several key substances that affected FB1 production, including starch and carotenoid. Subsequent studies demonstrated that the production of amylopectin, which is strongly linked to FB1 biosynthesis, was significantly increased in Med1 LxxLL motif mutants. In addition, the disruption of carotenoid metabolic genes decreased carotenoid content, thus stimulating FB1 biosynthesis in F. verticillioides. Taken together, our results provide valuable insights into how the Med1 LxxLL motif regulates FB1 biosynthesis in the mycotoxigenic fungus F. verticillioides.

Transcriptome analysis reveals the potential mechanism of carotenoids change in hepatopancreas under low-temperature storage from swimming crab (Portunus trituberculatus)

The hepatopancreas of swimming crab (Portunus trituberculatus) rich in carotenoids would undergo serious color deterioration during cold storage, and then made portunid lose its commodity value. In this study, we firstly elucidated the change mechanism of its carotenoids during storage at the molecular level using transcriptome technology. We concluded that low-temperature would inhibit aerobic respiration of portunid, leading to a lower pH and inducing the degradation of carotenoids. After that, longer cold storage time would increase the oxidative stress in portunid, resulting in a further decrease in carotenoids content. Finally, the strong autolysis of portunid could release carotenoids stored in other parts such as ovary to the external environment, resulting in the increase of carotenoids detection content. This research could provide a basis for further developing the fresh-keeping technology of portunid during low-temperature storage.

Effects of ultraviolet-light emitting diodes (UV-LEDs) on microbial inactivation and quality attributes of mixed beverage made from blend of carrot, carob, ginger, grape and lemon juice

Efficacy of ultraviolet light-emitting diodes (UV-LEDs) with peak and coupled emissions at 280, 365 and 280/365 nm on inactivation of E. coli K12 in mixed beverage (MB) was investigated. MB comprised of 31.6% carrot, 44.3% carob, 8.7% grape, 10.2% ginger, and 5.2% lemon juice. The impact of UV-LEDs on some physicochemical and phytochemical properties of MB was compared to that of heat treatment (70 °C, 120 s). While, UV-LED irradiation using coupled 280/365 nm for 40 min resulted in the highest inactivation of E. coli K12 (>4 log) out of tested wavelengths, the number of mesophilic bacteria (TAC), and yeast and molds (YM) in mixed beverage were reduced by 2.59 log CFU/mL (from 5.69 log CFU/mL of initial load), and 0.17 log CFU/mL (from 3.28 log CFU/mL of the initial load), respectively. Although, the color parameters slightly changed after irradiation, the color of MB did not show visual difference (ΔE = 0.94) compared to untreated samples. UV-LED treatment caused a significant increase in total phenolic compound (1.75-fold) and antioxidant capacity (4.60 fold) compared to heat-treated samples (p < 0.05). UV-LED treatment caused a decrease in carotenoid content (71.3%) lower than that of heat-treated samples (88.9%), indicating that UV-LED irradiation preserved the total carotenoid content better than the heat treatment. Industrial relevanceLight-emitting diodes (LEDs) are new sources of ultraviolet light utilized for non-thermal processing of foods. In this study, a static bench top unit was designed to investigate the efficacy of UV-LEDs with different treatment times and peak emissions by considering the inactivation of E. coli K12 in newly formulated mixed drink (MB). UV-LED irradiation of MB using coupled 280/365 nm for 40 min provided the highest microbial inactivation and preserved bioactive compounds better than the heat treatment. It can be proposed as an effective method for the processing of fruit juices which is rich in bioactive constituents.

Rapid metabolite response in leaf blade and petiole as a marker for shade avoidance syndrome

BackgroundShade avoidance syndrome (SAS) commonly occurs in plants experiencing vegetative shade, causing morphological and physiological changes that are detrimental to plant health and consequently crop yield. As the effects of SAS on plants are irreversible, early detection of SAS in plants is critical for sustainable agriculture. However, conventional methods to assess SAS are restricted to observing for morphological changes and checking the expression of shade-induced genes after homogenization of plant tissues, which makes it difficult to detect SAS early.ResultsUsing the model plant Arabidopsis thaliana, we introduced the use of Raman spectroscopy to measure shade-induced changes of metabolites in vivo. Raman spectroscopy detected a decrease in carotenoid contents in leaf blades and petioles of plants with SAS, which were induced by low Red:Far-red light ratio or high density conditions. Moreover, by measuring the carotenoid Raman peaks, we were able to show that the reduction in carotenoid content under shade was mediated by phytochrome signaling. Carotenoid Raman peaks showed more remarkable response to SAS in petioles than leaf blades of plants, which greatly corresponded to their morphological response under shade or high plant density. Most importantly, carotenoid content decreased shortly after shade induction but before the occurrence of visible morphological changes. We demonstrated this finding to be similar in other plant species. Comprehensive testing of Brassica vegetables showed that carotenoid content decreased during SAS, in both shade and high density conditions. Likewise, carotenoid content responded quickly to shade, in a manner similar to Arabidopsis plants.ConclusionsIn various plant species tested in this study, quantification of carotenoid Raman peaks correlate to the severity of SAS. Moreover, short-term exposure to shade can induce the carotenoid Raman peaks to decrease. These findings highlight the carotenoid Raman peaks as a biomarker for early diagnosis of SAS in plants.

Oxidative stress and antioxidant metabolites in wheat (Triticum aestivum L.) varieties during grain development under water deficit conditions

Two wheat (Triticum aestivum L.) varieties viz. WH 1105 and WH 1025 are subjected to drought stress. The non enzymatic antioxidant defense system which contains antioxidant metabolites such as ascorbic acid, glutathione and carotenoids contents were studied in drought sensitive and drought resistant varieties days after anthesis (DAA) in leaf and grain samples. As part of protective mechanism against drought, wheat plants produced more of ascorbic acid and glutathione with a concomitant decrease in carotenoid content. The increase in ascorbic acid and glutathione were more in WH 1025 than WH 1105. Carotenoids protect plants by minimizing ROS formation by quenching oxygen. The reduction in carotenoid content was observed in both wheat varieties days after anthesis (DAA) in leaf and grain samples but more reduction was observed in WH 1105 which is a drought sensitive variety of wheat. These antioxidant metabolites played a key role in protecting wheat plants against reactive oxygen species (ROS) mediated oxidative damage and their redox buffering capacity generates stress tolerance in drought tolerant wheat variety WH 1025.

Cmfhp Gene Mediates Fruiting Body Development and Carotenoid Production in Cordyceps militaris.

Cordyceps militaris fruiting bodies contain a variety of bioactive components that are beneficial to the human body. However, the low yield of fruiting bodies and the low carotenoid content in C. militaris have seriously hindered the development of the C. militaris industry. To elucidate the developmental mechanism of the fruiting bodies of C. militaris and the biosynthesis mechanism of carotenoids, the function of the flavohemoprotein-like Cmfhp gene of C. militaris was identified for the first time. The Cmfhp gene was knocked out by the split-marker method, and the targeted gene deletion mutant ΔCmfhp was obtained. An increased nitric oxide (NO) content, no fruiting body production, decreased carotenoid content, and reduced conidial production were found in the mutant ΔCmfhp. These characteristics were restored when the Cmfhp gene expression cassette was complemented into the ΔCmfhp strain by the Agrobacterium tumefaciens-mediated transformation method. Nonetheless, the Cmfhp gene had no significant effect on the mycelial growth rate of C. militaris. These results indicated that the Cmfhp gene regulated the biosynthesis of NO and carotenoids, the development of fruiting bodies, and the formation of conidia. These findings potentially pave the way to reveal the developmental mechanism of fruiting bodies and the biosynthesis mechanism of carotenoids in C. militaris.

The influence of carrot pretreatment, type of carrier and disc speed on the physical and chemical properties of spray-dried carrot juice microcapsules

Nowadays microencapsulation of pigments is widely applied to create stable powders. The aim of this study was to investigate the effect of thermal blanching as a form of pretreatment before pressing and carrier type on stability of microencapsulated carrot juice powder. Raw material used in the study was the carrot variety Kazan. One part of carrots was blanched before pressing the juice. Mixtures of low-crystallized maltodextrin (MD) with Arabic gum (AG) in different proportions (1:1, 2:1) and whey protein isolate (WPI) were used as carriers. Drying was carried out in a spray-drier at inlet air temperature of 160 °C. Two speeds of the disc were used (28,000; 39,000 rpm). Viscosity, soluble solid content, density, and carotenoid content were measured in juice. Water content, water activity, apparent and bulk density, size of particles, morphology, and carotenoid content were tested in powders. Carrot blanching resulted in higher viscosity, without influencing its density or soluble solid content of the juices in comparison with those without pretreatment. In most cases, blanching treatment caused a decrease in carotenoid content and increases in densities and diameters of powder particles. The change of carrier material from MD:AG mixtures to WPI caused an increase in diameter d50 and carotenoid content and decrease in density values.

Salicylic acid priming before and after accelerated aging process increases seedling vigor in aged soybean seed

ABSTRACTSeed vigor in soybean (Glycine max (L.) Merr.) declines under environmental stresses, and seed shows signs of aging. The aging effects may be alleviated, however, by seed priming with certain chemicals, such as salicylic acid (SA). The objective of this study was to investigate the effects of SA priming on activities of certain enzymes and lipid peroxidation in soybean seedlings under accelerated aging (AA) process. A factorial, completely randomized design with three replicates was used. Different aging durations (48 h and 72 h), SA priming solutions (0, 300 and 600 μM) and priming times (before aging, after aging and both before and after aging, i.e., double priming) were the experimental factors. Increasing aging duration significantly increased mean emergence time (MET) but decreased carotenoid content. Nonetheless, SA solution mitigated the adverse effect of seed deterioration on germination-related traits by increasing enzyme activity and reducing malondialdehyde (MDA) content, especially under double priming. A strong negative correlation (r = – 0.99**) was found between MDA content and chlorophyll a and chlorophyll b content. By contrast, the correlation between MDA content and MET (r = 0.95**) was found to be positive. The results suggested that double SA priming was an appropriate practical technique to improve seedling establishment from aged soybean seed.

Meloidogyne javanica parasitism on the vegetative growth and nutritional quality of carrots

ABSTRACT: Meloidogyne javanica is a plant-parasitic nematode that infects a wide range of vegetables. Its negative effects on crop yield and value are well documented. However, few studies have investigated the impact of the parasite on the nutritional value of vegetables. This study aimed to assess the effect of M. javanica parasitism on the vegetative characteristics, nematological parameters, chemistry composition and antioxidant activity of carrots. Seedlings were inoculated with 0 (control), 1000, 2500, or 5000 eggs and eventual second-stage juveniles (J2) of M. javanica. At 60 days after inoculation, plants were harvested and evaluated. Plants inoculated with 2500 eggs and J2 of M. javanica had higher root and tuber fresh weight than the control. Gall number increased with increasing inoculum density. The number of nematodes in the roots increased until 3000 specimens, decreasing thereafter. Proximate analysis revealed that plants inoculated with 1000 eggs and J2 of M. javanica or more had higher protein content in roots. In contrast, inoculation with 1775 nematodes or more resulted in a decrease in carotenoid content. There was no effect of inoculation on total phenolic content or antioxidant activity. Although, M. javanica infection did not have a marked impact on the nutritional quality of carrots, gall formation resulted in deformed roots of low commercial value.

Alteration of Carotenoid Metabolic Machinery by β-Carotene Biofortification in Rice Grains

To increase nutritional values as dietary sources of provitamin A and health-promoting antioxidants in rice grains, carotenoids have been biofortified in a Golden Ricelike variety, the stPAC (stPsy-2A-stCrtI) rice. In both of non-transgenic (NT) and stPAC seeds, total chlorophylls and carotenoids were gradually decreased during seed development while de novo biosynthesized carotenoids being comprised mainly of β-carotene, lutein and zeaxanthin were accumulated from early stage of 10 DAF and peaked at 20 DAF in stPAC seeds. The de novo production of carotenoids coincided with the high levels of transgene expression driven by the rice globulin gene promoter. Interestingly, expression levels of endogenous carotenoid metabolic pathway genes were the highest at 30 DAF in NT seeds whereas they were generally down-regulated in stPAC seeds, suggesting a negative feedback control mechanism of carotenoid metabolism by enhanced carotenoid production. The transgenic protein levels in stPAC seeds were not changed much during seed storage for up to 5 years, while carotenoid contents in the seeds were decreasing after 1 year of storage. The decrease in carotenoid contents was restored when the transgenic plants re-grown, supporting the reliability of transgenic pathways for carotenoid biofortification in rice grains. Thus, our results showed that transgene-driven biofortification of carotenoids was made and maintained over several transgenic generations with a possible negative feed-back control of endogenous carotenoid metabolism during seed development.

Hypnea musciformis (Wulfen) J. V. Lamour. (Gigartinales, Rhodophyta) responses to gasoline short-term exposure: biochemical and cellular alterations

ABSTRACT Presence of toxic compounds in marine coastal waters has increased exponentially since Industrial Revolution. In this way, we aimed to evaluate biochemical and physiological changes occurring within Hypnea musciformis after short-term exposure to gasoline. Hypnea musciformis was cultivated without gasoline and then exposed to various concentrations of it (0.001 % - 1.0 %, v/v) for periods of 30 min, 1 h, 12 h and 24 h. A Pricncipal Compound Analysis of UV-vis spectral window (200-700 nm) was able to discriminate gasoline-exposed samples according to both exposure time and gasoline concentration. Changes in carotenoid profile composition were observed. Decreased carotenoid content was associated to gasoline exposure time, being lutein and trans-β-carotene the major compounds found. Higher gasoline concentrations negatively interfered with phenolic compounds accumulation. In addition, increased gasoline concentrations corresponded to decreased intracellular starch grains content as well as increased its deposition on cell wall external surface. Data obtained allow us to conclude that gasoline can damage Hypnea musciformis physiology and cell morphology. This is important, considering Hypnea musciformis carotenoids and phenolics are potential biomarkers of environmental stress investigated, as well as its increased cell wall thickness to avoid gasoline diffusion.

Long-Term Effect on Bioactive Components and Antioxidant Activity of Thermal and High-Pressure Pasteurization of Orange Juice.

The long-term effect of thermal pasteurization (TP) and high-pressure processing (HPP) of orange juices stored under refrigeration, on the bioactive components and antioxidant activity, was compared. Total phenolic content (TPC), flavonoid, anthocyanin, and carotenoid contents, the individual content of major phenolic components, and the antioxidant activity, were evaluated in TP- and HPP-treated juices over a 36-day period. At day 0, no significant differences in TPC, and a decrease in carotenoid content after both treatments, were observed. TP caused a decrease of flavonoid and anthocyanin contents, while HPP increased flavonoid content. Three major phenolic components were identified: apigenin-6,8-di-C-glucoside, naringenin-7-O-rutinoside, and hesperetin-7-O-rutinoside, the latter increasing ca. 45% immediately after HPP. During storage, a decrease in TPC, and in the anthocyanin and carotenoid contents of both treated juices was observed, with higher anthocyanin and phenolic contents in HPP juices. A significant increase of hesperetin-7-O-rutinoside content was observed in HPP juice. Both treatments caused a decrease (26% and 13%, respectively) of antioxidant activity. Most of the kinetic profiles followed zero-order patterns, with HPP juices showing a considerably higher half-life than TP ones. These results clearly demonstrate the advantages of HPP for orange juice preservation allowing, also, their nutritional benefits to be enhanced by increasing the content of some bioactive components.

Quality preservation of walnut kernels using edible coatings

The objective of this work was to evaluate the performance of various edible coatings for preserving the quality of walnut kernels (W) during storage. Three edible coatings based on carboxymethyl cellulose (CMC), methyl cellulose (MC) and whey protein isolates (WP) were prepared. Coated and uncoated walnuts (WC) were stored for 210 days at room temperature (23±2 °C). After 210 days, WC presented the highest peroxide value (PV = 3.06 meqO2/kg), conjugated dienes (CD = 3.01) and trienes (CT = 0.31), pentanal, nonanal, hexanal, and decane, 5,6-bis (2,2-dimethylpropylidene) contents. Meanwhile, WMC showed the lowest PV (1.20 meqO2/kg), CD (2.26) and CT (0.17) and the lowest decrease in carotenoid content (0.60 mg/kg). The L* value measured in walnut oil decreased in all samples. MC, CMC and WP coatings showed protection on walnuts against the deterioration process. MC coating displayed the best performance.

Valorizations of carotenoids from sea buckthorn extract by microencapsulation and formulation of value-added food products

The use of highly functional carotenoids from different sources in food industry is limited mostly because of their poor water-solubility and low thermal stability. To overcome these drawbacks, the sea buckhorn (Hippophae rhamnoides L) carotenoids extract was encapsulated with whey proteins isolate and gum acacia by coacervation and freeze drying. Results from encapsulation efficiency, total carotenoids, confocal laser microscopy and FTIR indicated that the carotenoids molecules were successfully encapsulated within whey proteins isolate cages. The powder had a total carotenoids content of 2.82 ± 0.17 mg/g D.W. The confocal microscopy revealed the encapsulation of carotenoid compounds, with the formation of spheroids of 2–30 μm, whereas some of them merge together and generate coacervates that exceed 25 μm in diameter. Both the extract and the microencapsulated powder showed a significant antioxidant activity. The spectrum of the complex showed bands specific to the carotenoids, esters and dicarboxylic acids, but also bands specific for whey proteins. Also, formation of more hydrogen bonds within the coarcervates was suggested. The powder was tested further in muffins formulation. The products were characterized in terms of physico-chemical, microbiological, phytochemicals, antioxidant activity, texture, color parameters, sensory analysis and storage stability. The muffins had a total carotenoids content of 2.42 ± 1.29 mg/100 g D.W. and a corresponding antioxidant activity of 293.90 ± 2.07 μM Trolox/g D.W. A significant decrease in carotenoids content (up to 55%) and antioxidant activity was observed in the first 21 days of storage. A slight decrease in luminosity was observed, whereas no significant differences were found in a* and b* values.

Combined Alternaria dauci infection and water stresses impact carotenoid content of carrot leaves and roots

Carotenoids are important secondary metabolites involved in plant photosynthesis, vegetable nutritional quality but also in metabolic prevention in human health. Carrot represents one of the most important carotenoid intakes and is a very interesting model to study carotenoid metabolism. Till now, the knowledge about the impact of stress on carotenoid accumulation is limited. The purpose of this work was to investigate the impact of abiotic and biotic stresses applied separately or in combination on carotenoid accumulation in carrot leaves and roots. Results showed that combined stress decreased dramatically carotenoid content in both organs. In roots, the decrease in carotenoid content could be mostly associated in carrot response to A. dauci infection. Moreover, carotenoid and sugar contents were highly correlated, which suggests that stored metabolites are directly or indirectly involved in plant response to pathogen infection. In leaves, in contrast to results observed in roots, stresses impact carotenoid content depending on the genotype and the year. Moreover, carotenoid content variations were correlated to chlorophyll contents suggesting that a common mechanism of regulation for photosynthetic biosynthesis pigment exists.

UV-B radiation escalate allelopathic effect of benzoic acid on Solanum lycopersicum L.

The present study was undertaken to investigate the impact of UV-B radiation and benzoic acid (BA) on growth and metabolism of Solanum lycopersicum L. cv. Pusa ruby. Benzoic acid and UV-B radiation have impact on growth and development of Solanum. BA treatment in two concentrations 0.5mM and 1.0mM and UV-B alone and in combination (UV+BA) reduced root and shoot growth and biomass of the seedlings. BA with and without UV-B has negative impact on pigment, protein and sugar contents of the seedlings. Carotenoids showed varied responses to the stresses. BA decreased carotenoid content while UV-B increased the level of carotenoids. Lipid peroxidation and electrolyte leakage also increased under both stresses. Antioxidant enzyme activities significantly enhanced under BA treatment, but increase was further escalated when seedlings simultaneously exposed to UV-B radiation. It is evident that UV-B radiation enhanced the toxicity of BA in Solanum seedlings.