Lutein Content Research Articles

Changes in the content of carotenoids in potato tubers cultivated with or without the application of fungicides

AbstractIn this study, three cultivars and seven tetraploid potato clones were evaluated for two years in two cultivation systems (CS): without chemical protection against late blight development (NP) and with chemical protection (P). The objective of this study was to quantify the effect of chemical protection on the level of total carotenoids (TC) and individual carotenoids in potato tubers. The presented study showed that the content of TC in potato tubers is significantly affected by the CS and genotype. TC were higher in the system NP (mean 329.6 µg/100 g fresh weight [FW]) than in the system P (mean 206.2 µg/100 g FW). Although the development of late blight was observed only in the year 2019, a higher content of TC was observed in the system NP in both years. This dependence clearly show that CS without chemical protection favor carotenoids accumulation in potatotubers. In the case of lutein, the year had a significant impact on the concentration. The concentration of lutein in 2018 for the majority genotypes was higher (mean 72.1 µg/100 g FW), than in year 2019 (mean 37.3 µg/100 g FW), when late blight development wasobserved. The sharp decrease in lutein content in 2019 was probably caused by the development of late blight. A significant decrease of lutein content in potato tubers was observed in 2019 for all genotypes in system P and for five genotypes in system NP. It can be assumed that resistance mechanisms that occur during infection may have disturbed the accumulation of lutein in potato tubers.

Exogenous salicylic acid promotes carotenoid accumulation and antioxidant capacity in germinated maize kernels by regulating carotenoid biosynthetic pathway

Salicylic acid (SA), as an endogenous plant growth regulator, plays a crucial role in growth and development of plants. This study investigated the influence of varying concentrations of exogenous SA on the physiological and biochemical properties, antioxidant capacity, carotenoid content, and gene expression levels of germinated maize kernels. The results showed that the highest total phenolic and vitamin C contents were found with 0.10 mmol/L of SA, while the highest soluble protein, free amino acid and proline contents were found with 0.50 mmol/L of SA. The content of lutein and zeaxanthin reached the highest under 0.05 mmol/L of SA treatment, which were 18% and 22% higher than that of the control group, respectively. Meanwhile, the expression of seven key genes involved in carotenoid synthesis exhibited different degrees of up-regulation or down-regulation, which may be the reason for promoting carotenoid enrichment in germinated maize kernels. In addition, the antioxidant enzyme activities and antioxidant capacity in germinated maize kernels reached the highest value under the 0.1 mmol/L of SA treatment. Moreover, the correlation analysis results showed the transcription levels of some carotenogenic genes were significantly correlated with carotenoid content or antioxidant capacity. In summary, exogenous SA increased the content of bioactive components, especially carotenoids, and enhanced the antioxidant activity of germinated maize. Therefore, exogenous SA treatment may be used as an efficient germination method to improve the quality of germinated maize.

Microspheres as carriers of sea buckthorn carotenoids and tocols with antidiabetic potential: Effect of biopolymers, cross-linking and storage

The bioactivity of carotenoids and tocols is limited by their instability, hydrophobicity, and low bioavailability. Hence, the study aimed to design microspheres from sea buckthorn juice by ionotropic gelation to increase stability, ensure high content of carotenes, xanthophylls, tocopherols and tocotrienols and their antidiabetic activity. The effects of biopolymers, cross-linking and storage on the carotenoid and tocol profile of microspheres (identified and quantified by LC-PDA-QTOF-ESI-MS and UPLC-FL methods) and their in vitroα-amylase and α-glucosidase inhibitory activity were investigated. Microspheres containing sodium alginate/κ-carrageenan (4:1) had significantly high content of carotenoids and tocols, and antihyperglycemic activity (p < 0.05). The two-step cross-linking (1-calcium chloride, 2-chitosan) provided a 17% higher carotenoid content. Cross-linking with CaCl2 promoted high content of tocopherols but stability protection was provided by sodium alginate and CaCl2/chitosan (9:1) cross-linking (1.7-fold decrease in instability). The encapsulation using newly designed combinations of biopolymers and cross-linking could be an effective strategy to increase the stability and bioactivities of microspheres as nutraceuticals and smart food.

Evolution of Leaf Chlorophylls, Carotenoids and Phenolic Compounds during Vegetation of Some Croatian Indigenous Red and White Grape Cultivars.

During the ripening process of grapes, the grapevine leaves are the most active green organs that are important for photosynthesis, which is closely linked to the development and metabolism of the plant. The detection of plant pigments and phenolic compounds in grapevine leaves can be a good indicator of the ageing process, vine vigor and the plant's ability to respond to fungal attack. In a one-year study, the development of leaf chlorophylls, carotenoids and phenolic compounds during the ripening of six indigenous Croatian grape cultivars and the international cultivars Merlot and Chardonnay was investigated. The chlorophyll a/b ratio and total chlorophyll and total carotenoid concentrations were also investigated. PCA was used to highlight relevant information from the data with the aim of distinguishing individual compounds based on the cultivar and phenological stage. The leaf total hydroxycinnamic acid and flavan-3-ol concentrations decreased slowly during grape development, with the highest concentration immediately after flowering and the lowest during grape ripening. The concentrations of β-carotene, lutein and xanthophylls tended to decrease during bunch closure or veraison, while the concentration of chlorophylls a and b peaked during veraison and then decreased during grape ripening. This research will provide an opportunity to select cultivars with the physiological adaptation to synthesize secondary metabolites that are important for managing stress conditions.

Diagnosing arsenic-mediated biochemical responses in rice cultivars using Raman spectroscopy.

Rice (Oryza sativa) is the primary crop for nearly half of the world's population. Groundwater in many rice-growing parts of the world often has elevated levels of arsenite and arsenate. At the same time, rice can accumulate up to 20 times more arsenic compared to other staple crops. This places an enormous amount of people at risk of chronic arsenic poisoning. In this study, we investigated whether Raman spectroscopy (RS) could be used to diagnose arsenic toxicity in rice based on biochemical changes that were induced by arsenic accumulation. We modeled arsenite and arsenate stresses in four different rice cultivars grown in hydroponics over a nine-day window. Our results demonstrate that Raman spectra acquired from rice leaves, coupled with partial least squares-discriminant analysis, enabled accurate detection and identification of arsenic stress with approximately 89% accuracy. We also performed high-performance liquid chromatography (HPLC)-analysis of rice leaves to identify the key molecular analytes sensed by RS in confirming arsenic poisoning. We found that RS primarily detected a decrease in the concentration of lutein and an increase in the concentration of vanillic and ferulic acids due to the accumulation of arsenite and arsenate in rice. This showed that these molecules are detectable indicators of biochemical response to arsenic accumulation. Finally, a cross-correlation of RS with HPLC and ICP-MS demonstrated RS's potential for a label-free, non-invasive, and non-destructive quantification of arsenic accumulation in rice.

Variations of Carotenoids, Total Bioactive Contents, and Antioxidant Activity in Leaves of Medicago polymorpha

Medicago polymorpha L. (MP) is a herbaceous plant commonly known as “bur clover.” It is aboriginal to Central and Western Asia and extensively distributed around the world. This study determines the changes in carotenoids and antioxidant potential of different MP of different origins. The sample leaves were analyzed for identification and quantification of carotenoids using a reversed-phase HPLC system. The result showed nine carotenoids and pigments in each sample. The major carotenoid compounds were phytoene, phytofluene, neoxanthin and its isomer (9-Z-neoxanthin), violaxanthin, lutein along with their isomers (9-Z-lutein, 9′-Z-lutein), and all-E-β-carotene. The major pigments were 15-hydroxy-lactone chlorophyll a, pheophytin a, pheophytin a′, pyropheophytin a, divinyl chlorophyll a, chlorophyll b′, chlorophyll b, 13′-hydroxy-lactone chlorophyll b, and hydroxy pheophytin a′. The carotenoids were detected in considerable amounts in the samples from Lower Dir (213 μg/g), Swat (171 μg/g), and Buner (157 μg/g). Chlorophylls were higher in Lower Dir (203.4 μg/g), Swat (184.0 μg/g), and Buner (152.2 μg/g) and significantly lower amounts in Malakand samples (141.7 μg/g). The total carotenoids in Lower Dir (51.2%) were higher than in Swat (48.2%), Buner (50.8%), and Malakand samples (44.6%). The amounts of violaxanthin and lutein were significantly higher in Lower Dir (73.6%) samples, followed by Malakand (51.7%), whereas Buner and Swat samples showed the lowest levels. In conclusion, MP leaves are a good source of important carotenoids having potential antioxidant properties, which are highly correlated to the violaxanthin and lutein contents.

Longitudinal analysis of carotenoid content in preterm human milk

To describe the variability in carotenoid content of human milk (HM) in mothers of very to extremely low birth weight preterm infants throughout lactation and to explore the relationship between lutein in HM and the occurrence of retinopathy of prematurity (ROP) in preterm infants. We recruited healthy mothers along with their preterm infants that were born at gestational age 24 + 2 to 29 + 6 weeks or with a birth weight under 1500 g and were exclusively breastfed HM. Each participant provided up to 7 HM samples (2–10 ml) on day 0–3 and once a week until 6 weeks. Additionally, when possible, a blood sample was collected from the infant at week 6. Concentrations of the major carotenoids (lutein, zeaxanthin, beta-carotene, and lycopene) in all HM and blood samples were assessed and compared. Thirty-nine mother-infant dyads were included and 184 HM samples and 21 plasma samples were provided. Mean lutein, zeaxanthin, beta-carotene, and lycopene concentration decreased as lactation progressed, being at their highest in colostrum samples (156.9 vs. 66.9 vs. 363.9 vs. 426.8 ng/ml, respectively). Lycopene (41%) and beta-carotene (36%) were the predominant carotenoids in colostrum and up to 2 weeks post-delivery. Inversely, the proportion of lutein and zeaxanthin increased with lactation duration to account for 45% of the carotenoids in mature HM. Lutein accounted for 58% of the carotenoids in infant plasma and only 28% in HM. Lutein content of transition and mature HM did not differ between mothers of ROP and non-ROP infants.Conclusion Carotenoid content of HM was dynamic and varied between mothers and as lactation progressed. Infant plasma displayed a distinct distribution of carotenoids from HM.

High-Pressure Processing of Fruit Smoothies Enriched with Dietary Fiber from Carrot Discards: Effects on the Contents and Bioaccessibilities of Carotenoids and Vitamin E.

The effects of high-pressure processing (HPP) (450 MPa/600 MPa/3 min) on the carotenoid and vitamin E contents of smoothies made from strawberry, orange juice, banana and apple, and the same smoothies enriched with dietary fiber from discarded carrots were compared. The contents and bioaccessibilities of these compounds were also evaluated over the course of 28 days at 4 °C. The application of HPP in the formulations significantly increased the contents of β-cryptoxanthin, α-carotene and β-carotene and retained the contents of lutein, zeaxanthin and vitamin E compared to untreated samples. A decreasing trend in the content of each compound was observed with an increase in storage time. The application of HPP initially led to reductions in the bioaccessibility of individual compounds. However, overall, during storage, there was an increase in bioaccessibility. This suggests that HPP influences cell structure, favoring compound release and micelle formation. HPP is a sustainable method that preserves or enhances carotenoid extractability in ready-to-drink fruit beverages. Furthermore, the incorporation of dietary fiber from carrot processing discards supports circular economy practices and enhances the health potential of the product.

Comprehensive Analysis of Lutein and Loroxanthin in Scenedesmus obliquus: From Quantification to Isolation.

Carotenoids are hydrophobic pigments produced exclusively by plants, fungi, and specific microbes. Microalgae are well suited for the production of valuable carotenoids due to their rapid growth, efficient isoprenoid production pathway, and ability to store these compounds within their cells. The possible markets for bio-products range from feed additives in aquaculture and agriculture to pharmaceutical uses. The production of carotenoids in microalgae is affected by several environmental conditions, which can be utilized to enhance productivity. The current study focused on optimizing the extraction parameters (time, temperature, and extraction number) to maximize the yield of carotenoids. Additionally, the impact of various nitrogen sources (ammonia, nitrate, nitrite, and urea) on the production of lutein and loroxanthin in Scenedesmus obliquus was examined. To isolate the carotenoids, 0.20 g of biomass was added to 0.20 g of CaCO3 and 10.0 mL of ethanol solution containing 0.01% (w/v) pyrogallol. Subsequently, the extraction was performed using an ultrasonic bath for a duration of 10 min at a temperature of 30 °C. This was followed by a four-hour saponification process using a 10% methanolic KOH solution. The concentration of lutein and loroxanthin was measured using HPLC-DAD at 446 nm, with a flow rate of 1.0 mL/min using a Waters YMC C30 Carotenoid column (4.6 × 250 mm, 5 μm). The confirmation of carotenoids after their isolation using preparative chromatography was achieved using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with an atmospheric pressure chemical ionization (APCI) probe and UV-vis spectroscopy. In summary, S. obliquus shows significant promise for the large-scale extraction of lutein and loroxanthin. The findings of this study provide strong support for the application of this technology to other species.

The Effects of Jet-Milling and Pulsed Electric Fields on the Preservation of Spinach Juice Lutein Contents during Storage.

This study aimed to investigate the effects of jet-milling on the lutein extraction contents of spinach powder (SP), as well as the effects of pulsed electric field (PEF), as a non-thermal pasteurization technology, on the preservation of spinach juice (SJ) lutein contents. SP particles were divided into SP-coarse (Dv50 = 315.2 μm), SP-fine (Dv50 = 125.20 μm), and SP-superfine (Dv50 = 5.59 μm) fractions, and SP-superfine was added to SJ due to its having the highest contents of lutein extract. PEFs and thermal treatment were applied to evaluate the effects of preserving the lutein content of PEF during storage (25 days). The juice was then designated as untreated (no pasteurization), PEF-1,2 (SJ treated with PEF 20 kV/cm 110 kJ/L, 150 kJ/L), or Thermal-1,2 (SJ treated with 90 °C, 10 min and 121 °C, 15 min). The sizes and surface shapes of the superfine SP particles were more homogeneous and smoother than those of the other samples. SJ made with SP-superfine and treated with PEF had the highest lutein content and antioxidant activities among the group during storage. A complex of jet-milling and PEF could have great potential as a method to improve the lutein contents of lutein-enriched juice in the food industry.

Integrated Metabolomic and Transcriptomic Profiles Provide Insights into the Mechanisms of Anthocyanin and Carotenoid Biosynthesis in Petals of Medicago sativa ssp. sativa and Medicago sativa ssp. falcata.

The petals of Medicago sativa ssp. sativa and M. sativa ssp. falcata are purple and yellow, respectively. Free hybridization between M. sativa ssp. sativa and M. sativa ssp. falcata has created hybrids with various flower colors in nature. Moreover, the flower colors of alfalfa are closely correlated with yield, nutritional quality, stress tolerance and other agronomic characteristics. To elucidate the underlying mechanisms of flower color formation in M. sativa ssp. sativa and M. sativa ssp. falcata, we conducted an integrative analysis of the transcriptome and metabolome of alfalfa with three different petal colors (purple, yellow and cream). The metabolic profiles suggested that anthocyanins and carotenoids are the crucial pigments in purple and yellow flowers, respectively. A quantitative exploration of the anthocyanin and carotenoid components indicated that the accumulations of cyanidin, delphinidin, peonidin, malvidin, pelargonidin and petunidin derivatives are significantly higher in purple flowers than in cream flowers. In addition, the content of carotenes (phytoene, α-carotene and β-carotene) and xanthophylls (α-cryptoxanthin, lutein, β-cryptoxanthin, zeaxanthin, antheraxanthin and violaxanthin derivatives) was markedly higher in yellow flowers than in cream flowers. Furthermore, we found that delphinidin-3,5-O-diglucoside and lutein were the predominant pigments accumulated in purple and yellow flowers, respectively. The transcriptomic results revealed that twenty-five upregulated structural genes (one C4H, three 4CL, twelve CHS, two CHI, one F3H, one F3'H, one F3'5'H and four DFR) are involved in the accumulation of anthocyanins in purple flowers, and nine structural genes (two PSY, one ZDS, two CRTISO, two BCH, one ZEP and one ECH) exert an effect on the carotenoid biosynthesis pathway in yellow flowers. The findings of this study reveal the underlying mechanisms of anthocyanin and carotenoid biosynthesis in alfalfa with three classic flower colors.

Drum drying of whole maize flour enhances bioaccessibility of zeaxanthin, α-tocopherol, phytosterols, phenolics and flavonoids

The aim of the present study was to investigate the effect of drum drying of maize flour at slurry concentration of 30%–40% on phytonutrients content and their bioaccessibility. Content of tocopherols (TP), tocotrienol (TT), carotenoids, phytosterols, polyphenols and flavonoids, and antioxidant activity in drum dried maize was decreased. Bioaccessible content of stigmasterol, β-sitosterol and flavonoids was increased in drum dried maize. Bioaccessible content of campesterol and total phenolics was comparable to the bioaccessible content in raw maize. Bioaccessible content of TP, TT, lutein, zeaxanthin and β-carotene decreased in drum dried samples. DPPH + radical scavenging activity of bioaccessible fraction of drum dried maize was increased. The ferric reducing power was stable and total antioxidant activity decreased in bioaccessible fraction of drum dried sample. Percentage bioaccessibility of α-TP, phytosterols, zeaxanthin, phenolics, flavonoids and antioxidant activity was increased. Bioaccessibility of lutein and β-carotene retained, and γ-TP, δ-TP, α-, γ-, δ-TT decreased in drum dried sample. Overall, phytonutrients content was found to be low in drum dried samples, but there was retention of components in bioaccessible fraction which resulted higher percentage bioaccessibility of maize phytonutrients.

Tropical bloom-forming mesoalgae Cladophoropsis sp. and Laurencia sp.-responses to ammonium enrichment and a simulated heatwave.

Algal blooms are increasing worldwide, driven by elevated nutrient inputs. However, it is still unknown how tropical benthic algae will respond to heatwaves, which are expected to be more frequent under global warming. In the present study, a multifactorial experiment was carried out to investigate the potential synergistic effects of increased ammonium inputs (25 μM, control at 2.5 μM) and a heatwave (31°C, control at 25°C) on the growth and physiology (e.g., ammonium uptake, nutrient assimilation, photosynthetic performance, and pigment concentrations) of two bloom-forming algal species, Cladophoropsis sp. and Laurencia sp. Both algae positively responded to elevated ammonium concentrations with higher growth and chlorophyll a and lutein concentrations. Increased temperature was generally a less important driver, interacting with elevated ammonium by decreasing the algaes'%N content and N:P ratios. Interestingly, this stress response was not captured by the photosynthetic yield (Fv/Fm) nor by the carbon assimilation (%C), which increased for both algae at higher temperatures. The negative effects of higher temperature were, however, buffered by nutrient inputs, showing an antagonistic response in the combined treatment for the concentration of VAZ (violaxanthin, antheraxanthin, zeaxanthin) and thalli growth. Ammonium uptake was initially higher for Cladophoropsis sp. and increased for Laurencia sp. over experimental time, showing an acclimation capacity even in a short time interval. This experiment shows that both algae benefited from increased ammonium pulses and were able to overcome the otherwise detrimental stress of increasingly emerging temperature anomalies, which provide them a strong competitive advantage and might support their further expansions in tropical marine systems.

The impact of selected xanthophylls on oil hydrolysis by pancreatic lipase: in silico and in vitro studies

Lipase inhibition is one of the directions to control obesity. In vitro assays have confirmed the inhibitory effect of selected xanthophylls, including astaxanthin, fucoxanthinol, fucoxanthin, and neoxanthin. Similarly, an in-silico study also demonstrated the successful inhibition of pancreatic lipase by astaxanthin. Unfortunately, the efficacy of these protocols in the emulsion state typical of lipid digestion remains untested. To address this issue, the current study employed the pH–stat test, which mimics lipid digestion in the gastrointestinal tract, to evaluate native and prepared sea buckthorn and rapeseed oils with varying xanthophyll contents from 0 to 1400 mg/kg oil. Furthermore, a molecular docking of zeaxanthin and violaxanthin (commonly found in plant-based foods), astaxanthin (widely distributed in foods of marine origin) and orlistat (approved as a drug) was performed. The in-silico studies revealed comparable inhibitory potential of all tested xanthophylls (variation from − 8.0 to − 9.3 kcal/mol), surpassing that of orlistat (− 6.5 kcal/mol). Nonetheless, when tested in an emulsified state, the results of pH–stat digestion failed to establish the inhibitory effect of xanthophylls in the digested oils. In fact, lipolysis of native xanthophyll-rich sea buckthorn oil was approximately 22% higher than that of the xanthophyll-low preparation. The key insight derived from this study is that the amphiphilic properties of xanthophylls during the digestion of xanthophyll-rich lipids/meals facilitate emulsion formation, which leads to enhanced fat lipolysis.

Utilization of Biopolymer-Based Lutein Emulsion as an Effective Delivery System to Improve Lutein Bioavailability in Neonatal Rats.

Newborns' eyes and brains are prone to oxidative stress. Lutein has antioxidant properties and is the main component of macular pigment essential for protecting the retina, but has low bioavailability, thereby limiting its potential as a nutritional supplement. Oil-in-water emulsions have been used as lutein delivery systems. In particular, octenylsuccinated (OS) starch is a biopolymer-derived emulsifier safe to use in infant foods, while exhibiting superior emulsifying capacity. This study determined the effects of an OS starch-stabilized lutein emulsion on lutein bioavailability in Sprague-Dawley neonatal rats. In an acute study, 10-day-old pups received a single oral dose of free lutein or lutein emulsion, with subsequent blood sampling over 24 h to analyze pharmacokinetics. The lutein emulsion group had a 2.12- and 1.91-fold higher maximum serum lutein concentration and area under the curve, respectively, compared to the free lutein group. In two daily dosing studies, oral lutein was given from postnatal day 5 to 18. Blood and tissue lutein concentrations were measured. The results indicated that the daily intake of lutein emulsion led to a higher lutein concentration in circulation and key tissues compared to free lutein. The OS starch-stabilized emulsion could be an effective and safe lutein delivery system for newborns.

Building food composition tables: extraction methods to measure lutein and zeaxanthin concentrations in select Australian foods

SummaryThe lutein and zeaxanthin (L/Z) in food composition tables has infrequently utilised methods optimised for L/Z and comprehensive data are absent, such as in Australia. These absences limit quality dietary intake research. This study investigated optimisation of extraction methods for lutein and zeaxanthin in five Australian foods analysed by high‐performance liquid chromatography and photodiode array detection. The foods were broccoli, broccolini, baby spinach, baby orange capsicum, and dried goji berry. Twelve variations in extraction methods were investigated, including saponification, sonication, and solvent choice. L/Z concentrations differed by up to more than 125% between variations. Variation nine was best for all foods except zeaxanthin in broccoli where variation five or seven were best. The L/Z concentrations measured differed in Australian and United States data; existing data may therefore not be representative of the current food supply. Development of local Australian food composition data for lutein and zeaxanthin is warranted.

Improvements in the Appearance and Nutritional Quality of Tomato Fruits Resulting from Foliar Spraying with Silicon.

Research on silicon (Si), an element considered beneficial for plant growth, has focused on abiotic and biotic stress mitigation. However, the effect of Si on tomato fruit quality under normal growth conditions remains unclear. This study investigated the effects of applying different levels of Si (0 mmol·L-1 [CK], 0.6 mmol·L-1 [T1], 1.2 mmol·L-1 [T2], and 1.8 mmol·L-1 [T3]) in foliar sprays on tomato fruit quality cultivated in substrates, and the most beneficial Si level was found. Compared to CK, exogenous Si treatments had a positive influence on the appearance and nutritional quality of tomato fruits at the mature green, breaker, and red ripening stages. Of these, T2 treatment significantly increased peel firmness and single-fruit weight in tomato fruits. The contents of soluble sugars, soluble solids, soluble proteins, and vitamin C were significantly higher, and the nitrate content was significantly lower in the T2 treatment than in the CK treatment. Cluster analysis showed that T2 produced results that were significantly different from those of the CK, T1, and T3 treatments. During the red ripening stage, the a* values of fruits in the T2 treatment tomato were significantly higher than those in the other three treatments. Moreover, the lycopene and lutein contents of the T2 treatment increased by 12.90% and 17.14%, respectively, compared to CK. T2 treatment significantly upregulated the relative gene expression levels of the phytoene desaturase gene (PDS), the lycopene ε-cyclase gene (LCY-E), and the zeaxanthin cyclooxygenase gene (ZEP) in the carotenoid key genes. The total amino acid content in tomato fruits in the T2 treatment was also significantly higher than that of CK. In summary, foliar spraying of 1.2 mmol·L-1 exogenous Si was effective in improving the appearance and nutritional quality of tomato fruits under normal growth conditions. This study provides new approaches to further elucidate the application of exogenous silicon to improve tomato fruit quality under normal conditions.

Using Raman spectroscopy for early detection of resistance-breaking strains of tomato spotted wilt orthotospovirus in tomatoes.

Tomato spotted wilt (TSW) disease caused by tomato spotted wilt orthotospovirus (TSWV, Orthotospovirus tomatomaculae) poses a significant threat to specialty and staple crops worldwide by causing over a billion dollars in crop losses annually. Current strategies for TSWV diagnosis heavily rely on nucleic acid or protein-based techniques which require significant technical expertise, and are invasive, time-consuming, and expensive, thereby catalyzing the search for better alternatives. In this study, we explored the potential of Raman spectroscopy (RS) in early detection of TSW in a non-invasive and non-destructive manner. Specifically, we investigated whether RS could be used to detect strain specific TSW symptoms associated with four TSWV strains infecting three differentially resistant tomato cultivars. In the acquired spectra, we observed notable reductions in the intensity of vibrational peaks associated with carotenoids. Using high-performance liquid chromatography (HPLC), we confirmed that TSWV caused a substantial decrease in the concentration of lutein that was detected by RS. Finally, we demonstrated that Partial Least Squares-Discriminant Analysis (PLS-DA) could be used to differentiate strain-specific TSW symptoms across all tested cultivars. These results demonstrate that RS can be a promising solution for early diagnosis of TSW, enabling timely disease intervention and thereby mitigating crop losses inflicted by TSWV.

Analysis of the relationship between color and natural pigments of tobacco leaves during curing

Color is one of the most important indicators for the flue-cured tobacco quality. The color change of tobacco has a great relationship with the natural pigments in the tobacco. The relationship between color characteristics and the content of natural pigments in tobacco leaves during curing was investigated. The middle part of variety K326 tobacco was taken at each key time point during the curing process to determine the changes of color characteristics, moisture, pigment and polyphenol content. The results showed that moisture content of wet basis of tobacco gradually decreased from 72 to 18% during the curing process, the b* value increased and then decreased, and the a* value increased significantly. The lutein and β-carotene content decreased to 63.83 μg/g and 28.3 μg/g, respectively. The total polyphenols content increased to 50.19 mg/g. Meanwhile, the a* value was significantly and positively correlated with polyphenols content and negatively correlated with pigments content. Cluster analysis showed that the samples were divided into three categories: samples with the curing time of 0 h, 24–72 h, and 84–132 h. These results demonstrated that the color change of tobacco during curing process can be divided into three stages from the perspective of chemical composition, which are strongly related to the degradation of pigments and the transformation of polyphenols.

Variation in the concentrations of phenolic compounds and carotenoids in the grain of a large collection of Triticum durum Desf. accessions

Carotenoids and phenolic compounds play an important role in durum wheat grain by influencing its health-promoting properties and processing suitability. The aim of this study was to determine the variability in the concentrations of carotenoids and phenolic compounds in genetic resources that can be potentially used to breed new durum wheat varieties. A total of 101 spring accessions from Germplasm Resource Information Network (GRIN) and three reference cultivars were examined. The concentrations of eight flavonoids (apigenin, catechin, kaempferol, luteolin, naringenin, quercetin, rutoside, and vitexin), eleven bound phenolic acids (4-hydroxybenzoic, caffeic, chlorogenic, ferulic, gallic, p-coumaric, protocatechuic, sinapic, syringic, t-cinnamic, vanillic acids, and vanillin), and three carotenoids (lutein, zeaxanthin, and β-carotene) were determined. Quercetin and naringenin were the predominant flavonoids (45.7 and 33.7 mg kg−1, respectively), whereas ferulic acid and t-cinnamic acid were the predominant phenolic acids (660.1 and 498.2 mg kg−1, respectively). The grain of ten accessions (9.8%) contained more than 3 mg kg−1 of lutein, and lutein concentration exceeded 6 mg kg−1 in the grain of five accessions (4.9%). The antioxidant activity of grain (ABTS) was positively correlated with the total content of all analyzed metabolites (r = 0.5435), but no linear correlations were observed between ABTS and each of the three examined groups of compounds.