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Analyzing carotenoids of snow algae by Raman microspectroscopy and high-performance liquid chromatography
摘要： We tested the potential of Raman microspectroscopy to determine carotenoid pigments — both primary (lutein, beta-carotene) and secondary (astaxanthin) carotenoids — in the different species and life-cycle stages of snow algae from the order Chlamydomonadales (Chlorophyta). We compared the performance of Raman spectrometry to a reference method of biological pigment analysis, high-performance liquid chromatography (HPLC). The three main carotenoid Raman bands of the astaxanthin-rich red cysts were located at 1520, 1156 and 1006 cm-1. The shifts (orange aplanozygotes and green motile cells with flagella) in the position of the ν1(C=C) Raman band of the polyenic chain is consistent with the expected changes in the ratios of the various carotenoid pigments. Flagellated green cells commonly contain lutein as a major carotenoid, together with minor amounts of β-carotene and varying amounts of antheraxanthin, violaxanthin and neoxanthin. Aplanozygotes contain mixtures of both primary and secondary carotenoids. In most cases, the ν1(C=C) band is an overlapping set of bands, which is due to the signal of all carotenoid pigments in the sample, and a deconvolution along with the band position shifts (mainly ν1) could be used to characterize the mixture of carotenoids. However, the ability of Raman spectroscopy to discriminate between structurally slightly differing carotenoid pigments or several carotenoids in an admixture in an unknown biological system remains limited.
关键词： HPLC,Snow algae,Biomarker,Raman spectroscopy,Exobiology,Carotenoids
更新于2025-09-23 15:22:29
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Determination of Pigments in Virgin and Extra-Virgin Olive Oils: A Comparison between Two Near UV-Vis Spectroscopic Techniques
摘要： The colour of olive oil is due to the presence of natural pigments belonging to the class of carotenoids, chlorophylls, and their derivatives. These substances, other than being responsible for the colour, an important qualitative feature of the oil, have antioxidant and, more generally, nutraceutical properties and their quantification can be related to the product’s quality and authenticity. In this work, we have quantified the total amount of carotenoids and chlorophylls’ derivatives in several virgin and extra-virgin olive oils produced in Italy, by using two different methods that are based on near-ultraviolet-visible absorption spectroscopy. The first method defines two indexes, K670 and K470, related to absorbance values of oil at wavelengths of 670 and 470 nm, respectively. The second method is based on the mathematical deconvolution of the whole absorption spectrum of the oil to obtain the concentrations of four main pigments present in olive oils: β-carotene, lutein, pheophytin A, and pheophytin B. The concentrations of the total carotenoids and total chlorophylls’ derivatives, as obtained by the two spectroscopic methods, are compared and the results are discussed in view of the practical usefulness of spectroscopic techniques for a fast determination of pigments in olive oil.
关键词： EVOO,colour,ultraviolet-visible light,extra-virgin olive oil,chlorophylls,pigments,carotenoids,spectroscopy,quality,light absorption
更新于2025-09-23 15:22:29
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Carotenoids co-localize with hydroxyapatite, cholesterol, and other lipids in calcified stenotic aortic valves. Ex vivo Raman maps compared to histological patterns
摘要： Unlike its application for atherosclerotic plaque analysis, Raman microspectroscopy was sporadically used to check the sole nature of bioapatite deposits in stenotic aortic valves, neglecting the involvement of accumulated lipids/lipoproteins in the calcific process. Here, Raman microspectroscopy was employed for examination of stenotic aortic valve leaflets to add information on nature and distribution of accumulated lipids and their correlation with mineralization in the light of its potential precocious diagnostic use. Cryosections from surgically explanted stenotic aortic valves (n=4) were studied matching Raman maps against specific histological patterns. Raman maps revealed the presence of phospholipids/triglycerides and cholesterol, which showed spatial overlapping with one another and Raman-identified hydroxyapatite. Moreover, the Raman patterns correlated with those displayed by both von-Kossa-calcium- and Nile-blue-stained serial cryosections. Raman analysis also provided the first identification of carotenoids, which co-localized with the identified lipid moieties. Additional fit concerned the distribution of collagen and elastin. The good correlation of Raman maps with high-affinity staining patterns proved that Raman microspectroscopy is a reliable tool in evaluating calcification degree, alteration/displacement of extracellular matrix components, and accumulation rate of different lipid forms in calcified heart valves. In addition, the novel identification of carotenoids supports the concept that valve stenosis is an atherosclerosis-like valve lesion, consistently with their previous Raman microspectroscopical identification inside atherosclerotic plaques.
关键词： lipids,Valve calcification,Raman microspectroscopy,stenosis,carotenoids
更新于2025-09-23 15:22:29
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UV-visible scanning spectrophotometry and chemometric analysis as tools for carotenoids analysis in cassava genotypes (Manihot esculenta Crantz)
摘要： In this study, the metabolomics characterization focusing on the carotenoid composition of ten cassava (Manihot esculenta) genotypes cultivated in southern Brazil by UV-visible scanning spectrophotometry and reverse phase-high performance liquid chromatography was performed. Cassava roots rich in β-carotene are an important staple food for populations with risk of vitamin A deficiency. Cassava genotypes with high pro-vitamin A activity have been identified as a strategy to reduce the prevalence of deficiency of this vitamin. The data set was used for the construction of a descriptive model by chemometric analysis. The genotypes of yellow-fleshed roots were clustered by the higher concentrations of cis-β-carotene and lutein. Inversely, cream-fleshed roots genotypes were grouped precisely due to their lower concentrations of these pigments, as samples rich in lycopene (red-fleshed) differed among the studied genotypes. The analytical approach (UV-Vis, HPLC, and chemometrics) used showed to be efficient for understanding the chemodiversity of cassava genotypes, allowing to classify them according to important features for human health and nutrition.
关键词： Chemometrics,cassava genotypes,partial metabolome,descriptive models,UV-vis,carotenoids,RP-HPLC
更新于2025-09-23 15:22:29
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Classification of Oil Palm Fresh Fruit Bunches (FFB) Using Raman Spectroscopy
摘要： The current practice in determining oil palm fresh fruit bunches (FFB) ripeness is by its colour which could be inaccurate. This study investigates the classification of oil palm FFB ripeness using Raman spectroscopy. A feature extraction model is developed based on the different organic compositions that contribute to the ripeness classification. Samples are collected according to the Malaysian Palm Oil Board (MPOB) standards which are unripe, underripe, ripe, overripe, and rotten. Different characteristics of the Raman shift were detected which represent the material composition for each sample. The Raman intensity of the oil palm fruit increases from unripe to ripe before decreasing to rotten due to the carotenoid content in the fruit. In conclusion, Raman spectroscopy is a suitable technique to observe the changes in the composition of oil palm fruit classified by its ripeness.
关键词： oil palm fruit,Raman spectroscopy,carotenoids,ripeness
更新于2025-09-23 15:21:01
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Application of optical methods to determine the stability of emulsions containing carotenoids
摘要： Colloidal systems such as emulsions are commonly used to improve aesthetics but they may also be applied to deliver active ingredients. Recently, group of pigments known as carotenoids, have been added to emulsions as active compounds mainly due to their antioxidant properties. The stability of these formulations is a critical parameter for both pharmaceutical and cosmetics industries. Therefore, in this study optical methods such as multiple light scattering and laser diffraction were applied to determine the stability of various emulsions containing carotenoids such as β-carotene, lycopene and astaxanthin. The results of both methods proved that the type of carotenoid added did not influence the emulsions stability. The stability of emulsions depends mainly on the preparation methods and on the type of emulsifier applied.
关键词： carotenes,stability studies,xanthophylls,carotenoids,semisolid formulations,particle size
更新于2025-09-19 17:15:36
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White and red LEDs as two-phase batch for cyanobacterial pigments production
摘要： Carotenoids and phycobiliproteins have a high economic value, due to their wide range of biological and industrial applications. The implementation of strategies to increase their production, such as the application of two-phase light cultivation systems, can stimulate pigments production, increasing economic turnover. In this sense, Cyanobium sp. was grown in seven different two-phase white/red cultivation arrangements, varying the time of each light from 0 to 21 days. Biomass, photosynthetic activity, pigments profile and antioxidant capacity were measured along time. Red light increased photosynthetic activity and pigments content (ca. 1.8-fold), and the use of a two-phase cultivation system generally raised bioactivity and production of phytochemicals. Among the studied, the optimal cultivation condition was found with 10 days of white followed by 4 days of red light. The optimized growth led to a productivity of 137.4 ± 0.8 mg.L-1.d-1 of biomass, 17.0 ± 0.2 mg.L-1.d-1 of total phycobiliproteins and 4.5 ± 0.2 mg.L-1.d-1 of carotenoids
关键词： cyanobacteria,carotenoids,phycobiliproteins,antioxidant capacity,light-emitting diode
更新于2025-09-16 10:30:52
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Color Development and Phytochemical Changes in Mature Green Chili (Capsicum annuum L.) Exposed to Red and Blue Light-Emitting Diodes
摘要： Exposure of mature green ‘Takanotsume’ chili fruit to blue and red light-emitting diodes (LEDs) was investigated. The red LED accelerated the red color development of chili as indicated by higher a* and chroma values, as well as lower hue angle and total chlorophyll compared to the blue LED and darkness (control). These were linked to increases in β-carotene, free-capsanthin and total carotenoids. The carotenoid biosynthesis-related genes: lycopene-β-cyclase (Lcyb), β-carotene hydroxylase (CrtZ), and capsanthin/capsolubin synthase (Ccs) were up-regulated by the red LED after 2 days of the experiment. The blue LED was more effective in increasing the expression of the phytoene synthase (Psy) gene at day 1 of experiment. The total phenolic, vitamin C content, and antioxidant capacity were also higher in the blue LED-treated chili. Results suggest that the responses of each carotenoid-related gene to the light wavelengths and the accumulation of phytochemicals are specific characteristics of this chili cultivar.
关键词： phytochemicals,carotenoids,LEDs,carotenoid biosynthesis,mature green chili,Antioxidant
更新于2025-09-12 10:27:22
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Variation in the primary and secondary metabolites derived from the isoprenoid pathway in the Perovskia species in response to different wavelengths generated by light emitting diodes (LEDs)
摘要： Perovskia is a valuable medicinal plant of the Lamiaceae family with different pharmaceutical and industrial applications. This study evaluates the variations in essential oil yield, composition and polyphenolic content as well as some primary metabolites such as chlorophyll and carotenoid contents in Perovskia abrotanoides and P. atriplicifolia in response to four artificial light treatments including red, blue, red-blue, and white generated by LEDs as compared with the same traits under natural lighting used as control. Essential oil yield in P. abrotanoides is observed to range from 0.41% under the red-blue light to 2.66% under the white light treatment. The highest (1.9%) and lowest (1.48%) essential oil contents in P. atriplicifolia are recorded under the blue and white light treatments, respectively. GCeMS analysis identifies camphor (4.8–29.52%), borneol (4.62–13.47%), 1,8-cineole (4.24–31.01%), trans-caryophellene (3.9–10.15%), and α-humulene (3.26–9.13%) as the major compounds in the species studied subjected to the lighting treatments. Based on cluster and principal component analyses (PCA), three major groups are determined in both species and among all the treatments. Accordingly, LED wavelengths show a reducing effect on the monoterpene content but a tendency for increasing the sesquiterpene content in the species studied. Finally, elevated levels of polyphenolic compounds and carotenoids are detected in both species under the blue light. The findings might be useful for selecting valuable compounds in the species studied for further evaluations.
关键词： Light,Carotenoids,Essential oil,Flavonoid,Perovskia,Phenolic
更新于2025-09-12 10:27:22
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Influence of spectral intensity and quality of LED lighting on photoacclimation, carbon allocation and high-value pigments in microalgae
摘要： Tailoring spectral quality during microalgal cultivation can provide a means to increase productivity and enhance biomass composition for downstream biorefinery. Five microalgae strains from three distinct lineages were cultivated under varying spectral intensities and qualities to establish their effects on pigments and carbon allocation. Light intensity significantly impacted pigment yields and carbon allocation in all strains, while the effects of spectral quality were mostly species-specific. High light conditions induced chlorophyll photoacclimation and resulted in an increase in xanthophyll cycle pigments in three of the five strains. High-intensity blue LEDs increased zeaxanthin tenfold in Rhodella sp. APOT_15 relative to medium or low light conditions. White light however was optimal for phycobiliprotein content (11.2 mg mL?1) for all tested light intensities in this strain. The highest xanthophyll pigment yields for the Chlorophyceae were associated with medium-intensity blue and green lights for Brachiomonas submarina APSW_11 (5.6 mg g?1 lutein and 2.0 mg g?1 zeaxanthin) and Kirchneriella aperta DMGFW_21 (1.5 mg g?1 lutein and 1 mg g?1 zeaxanthin), respectively. The highest fucoxanthin content in both Heterokontophyceae strains (2.0 mg g?1) was associated with medium and high white light for Stauroneis sp. LACW_24 and Phaeothamnion sp. LACW_34, respectively. This research provides insights into the application of LEDs to influence microalgal physiology, highlighting the roles of low light on lipid metabolism in Rhodella sp. APOT_15, of blue and green lights for carotenogenesis in Chlorophyceae and red light-induced photoacclimation in diatoms.
关键词： Carbon allocation,Phycobiliproteins,Microalgal physiology,LEDs,Carotenoids
更新于2025-09-12 10:27:22