An improved method for fast and selective separation of carotenoids by LC-MS

Development of a screening method for the determination of carotenoids in ham sausage, juice, and cookies by an improved Bligh-Dyer method and LC-MS/MS

A screening method of 23 carotenoids in foods, such as ham sausage, juice, and cookies, was proposed using an improved Bligh-Dyer method that can satisfy the extraction requirements of common carotenoids with different physicochemical properties, including free and esterified carotenoids, by collecting the aqueous and organic phases simultaneously. Purification was then performed by loading the aqueous phase onto a hydrophile-lipophile balance (HLB) column; a methanol-water solution was used for washing, and the organic phases and additional chloroform were used for elution. By optimizing this step, interference from hydrophilic compounds and neutral triglycerides was effectively eliminated, and the matrix suppression effect after purification was greater than -16.3%. Finally, the extract was analyzed by ultrahigh performance liquid chromatography-quadrupole-orbitrap high-resolution mass spectrometry. The results showed that the 23 carotenoids showed a good linear relationship in the range of 0.01-0.2 µg/mL, and the limits of quantification (signal-to-noise ratio ≥10) were from 0.02 to 0.05 mg/kg. The average recoveries were 80.1%-98.7%, with relative standard deviation ≤10%. The proposed method can simultaneously identify and quantify 23 carotenoids in foods with high throughput, sensitivity, and reliability.

Beneficial properties of Drimia numidica leaf methanolic extract against the cytogenotoxic effects of mitomycin C on human lymphocytes

This study investigated the phytochemical profile of Drimia numidica leaf methanolic extract, as well as its cyto-genotoxic and cyto/genoprotective potential against mitomycin C (MMC) mediated effects on healthy human lymphocytes. Photosynthetic pigments, trace elements, and secondary metabolites were estimated and/or identified in methanolic extract of mature leaves, and the latter was further used for assessing its in vitro biological effects on MMC-free and/or MMC-treated human lymphocytes (at low, non-toxic concentrations of 0.001 and 0.01% v/v). The results showed that D. numidica leaf methanolic extract, being rich in carotenoids, phenolics, flavonoids, organic acids and bufadienolides, could be protective against MMC mediated cyto/genotoxic potential in healthy human lymphocytes. Biomolecules possessing antioxidant and antitumor potential, such as beta-carotene and lutein among others, chlorogenic acid, caffeic acid and their derivatives, minerals such as Si, as well as apigenin- and luteolin-derived glycosides, either individual or in a mixture, could be beneficial rather than harmful, at least at the extract concentrations tested. Although further in vitro and in vivo studies are still needed for elucidating the beneficial (individual and/or additive/synergistic) role of those compounds, the results of the present study are quite promising, thus encouraging new challenges for the appropriate utilization of D. numidica leaf extract.

Bacterial Carotenoids: Extraction, Characterization, and Applications

Natural carotenoids are secondary metabolites that exhibit antioxidant, anti-inflammatory, and anti-cancer properties. These types of compounds are highly demanded by pharmaceutical, cosmetic, nutraceutical, and food industries, leading to the search for new natural sources of carotenoids. In recent years, the production of carotenoids from bacteria has become of great interest for industrial applications. In addition to carotenoids with C40-skeletons, some bacteria have the ability to synthesize characteristic carotenoids with C30-skeletons. In this regard, a great variety of methodologies for the extraction and identification of bacterial carotenoids has been reported and this is the first review that condenses most of this information. To understand the diversity of carotenoids from bacteria, we present their biosynthetic origin in order to focus on the methodologies employed in their extraction and characterization. Special emphasis has been made on high-performance liquid chromatography-mass spectrometry (HPLC-MS) for the analysis and identification of bacterial carotenoids. We end up this review showing their potential commercial use. This review is proposed as a guide for the identification of these metabolites, which are frequently reported in new bacteria strains.

Formation mechanism of isoprene compounds degraded from carotenoids during fermentation of goji wine

Fermented goji wine as a functional wine is made from yeast fermentation. To our knowledge, fermented goji wine still has a problem with insufficient characteristic aroma. Research has shown that some isoprene compounds with characteristic aromas may improve the aroma of goji wine. Therefore, the present study aimed to investigate the mechanism of isoprene compound production by carotenoid degradation during the fermentation of goji wine. It was found that C1–C6, C5–C6, C6–C7, C7–C8, C8–C9 and C9–C10 were the most easily degraded sites in carotenoids under seven different pretreatment conditions (mechanical treatment, pectinase treatment, adjustment of pH, autoclave treatment, SO2 treatment, oxidation treatment and light treatment). Meanwhile, breaking different sites, different aroma contributions such as woody, rose, fruity and grassy aromas were found. Single-factor simulation experiments of goji wine during the fermentation showed that the metabolites in the fermentation process caused the degradation of carotenoids and most were volatile aroma compounds. These results may help improve the brewing process to enhance the aroma of goji wine.

An improved method for the separation of carotenoids and carotenoid isomers by liquid chromatography-mass spectrometry

Carotenoids consist of a series of conjugated isoprene units that are characteristically highly conjugated through double bonds, leading to the formation of many isomers that are susceptible to oxidation and other chemical modifications. Extreme hydrophobicity and high complexity make carotenoids difficult to identify and quantify. We implemented the use of a common Syncronis C18 column with strong eluting solvent, here isopropanol, to successfully separate a mixture of 23 carotenoids standards with different structural properties. In addition, the method differentiated between three groups of isomeric carotenoids (lycopene/δ-carotene/γ-carotene/ε-carotene/α-carotene/β-carotene, α-cryptoxanthin/β-cryptoxanthin, and zeaxanthin/lutein) by optimizing the gradient profile and using liquid chrmatography-mass spectrometry. The LOD ranged from 0.05 to 5.51 ng/mL, and the recovery of carotenoids in Mytilus coruscus was from 63.54 to 93.25%, with standard deviations <10%. Twenty-five carotenoids were detected with a total content of 857 ± 55.1 mg/kg, and three isomeric carotenoids were identified: ε-carotene, α-carotene, and β-carotene. Our results show that this methodology is a significant improvement over other alternatives for analyzing carotenoids because of its compatibility with carotenoids of different categories, and most importantly, its ability to resolve isomeric carotenes, which is significant not only for assessing carotenoid species, but also for the tracing of metabolic pathways of carotenoids.

Analysis of Tomato Carotenoids: Comparing Extraction and Chromatographic Methods

Background: Tomatoes (Solanum lycopersicum) are an economically and nutritionally important crop colored by carotenoids such as lycopene and β-carotene. Market diversification and interest in the health benefits of carotenoids has created the desire in plant, food, and nutritional scientists for improved extraction and quantification protocols that avoid the analytical bottlenecks caused by current methods. Objective: Our objective was to compare standard and rapid extraction as well as chromatographic separation methods for tomato carotenoids. Method: Comparison was based on accuracy and the ability to discriminate between alleles and genetic backgrounds. Estimates of the contribution to variance in the presence of genetic and environmental effects were further used for comparison. Selections of cherry and processing tomatoes with varying carotenoid profiles were assessed using both established extraction and HPLC-diode array detector (HPLC-DAD) methods and rapid extraction and ultra-HPLC-DAD (UHPLC-DAD) protocols. Results: Discrimination of alleles in samples extracted rapidly (<5 min/sample) was similar to samples extracted using a standard method (10 min/sample), although carotenoid concentrations were lower due to reduced extraction efficiency. Quantification by HPLC-DAD (21.5 min/sample) and UHPLC-DAD (4.2 min/sample) were comparable, but the UHPLC-DAD method could not separate all carotenoids and isomers of tangerine tomatoes. Random effects modeling indicated that extraction and chromatographic methods explained a small proportion of variance compared with genetic and environmental sources. Conclusions: The rapid extraction and UHPLC-DAD methods could enhance throughput for some applications compared with standard protocols.