Safflower is an important industrial oil seed and bioenergy crop in semi-arid subtropical regions due to its potential to grow on marginal land and having good percentage of seed oil contents which ...is an important parameter for biofuel production. However, it is an ignored crop in Pakistan. In order to improve the crop productivity and reduce the use of agrochemicals for sustainable biodiesel feedstock production, an experiment was conducted for two years to improve the fatty acid composition and oil quality of Carthamus tinctorius L. (safflower) by the inoculation of Azospirillum and Azotobacter alone as well as in combined application with nitrogen and phosphate (NP) fertilizers on cultivars Thori and Saif-32 under field conditions. Separation and quantification of fatty acids were done on precise comprehensive two-dimensional gas chromatography (GC×GC). The results showed that fatty acid profile specifically monounsaturated fatty acids i-e oleic acid (C18:1) was significantly improved by Azospirillum supplemented with the quarter dose of NP fertilizers (SPQ) with concomitant decrease in polyunsaturated fatty acids by the respective treatment. Oil quality attributes such as acid value, saponification number, iodine value, refractive index and free fatty acid contents were reduced by the application of Azotobacter and Azospirillum in combination with half and quarter doses of NP fertilizers treatments (BTH, SPH, BTQ and SPQ). The reduction in these variables is positively linked with improved biodiesel yield and quality. It can be concluded that application of Azospirillum and Azotobacter not only reduced the use of NP fertilizers up to 50%-75% but also improved the oil quality in order to obtain environment friendly, sustainable and green fuel.
Five Vitis vinifera L. cultivars Shiraz, Cabernet Sauvignon, Riesling, Chardonnay and Pinot Gris at different E-L development stages were harvested in two experimental vintages. Temperature and ...rainfall data of the growing period were obtained from the Australian Government Bureau of Meteorology. Free terpene concentrations of all harvested grape samples were analysed using HS-SPME-GC-MS. One-way ANNOVA was performed to evaluate the significance of changes in terpene concentrations at different maturation stages. More analysis of the data is provided in “Free terpene evolution during the berry maturation of five Vitis vinifera L. cultivars” 1.
•Terpene profiles could discriminate five wine grape varieties at five E-L stages.•Shiraz and Cabernet Sauvignon had consistent evolution patterns for total norisoprenoids and ...sesquiterpenes.•(E)-β-Damascenone concentration increased along with the berry maturation in all varieties.•Sesquiterpenes showed a ‘U’ shape evolution pattern for most varieties in both vintages.
Terpenes and their derivatives, terpenoids, are important biomarkers of grape quality as they contribute to flavor and aroma of grape and wine. The evolution of terpene and terpenoids throughout grapevine phenological development cycles is not well understood. The current study investigated the volatile profiles of free terpene and terpenoid of five widely grown Vitis vinifera L. cultivars (Shiraz, Cabernet Sauvignon, Riesling, Chardonnay and Pinot Gris), at different phenological stages from fruit-set to harvest. 17 Monoterpenoids, 3 norisoprenoid and 13 sesquiterpenoids were identified and quantified. Discriminant analysis revealed that for each grape cultivar, free terpene profiles at different E-L stages were distinctive. When integrating total sugar, total terpenes and the cumulated heat index, it could be found that flavor ripening was more consistent with sugar ripening in the warmer vintage 2016. Comparing the two red wine varieties, the overall development patterns of total monoterpenes, norisoprenoids and sesquiterpenes were similar.
•Cryotrapping analyte as part of the sampling step facilitates efficient introduction to the GC.•Cryofocussing maximises resolution for splitless SPME injection and allows multiple injections.•Novel ...cryofocussing combined with multidimensional analysis enable enhanced separations.•Various cryomodulation methods are used with comprehensive 2D GC techniques.•Cryotrapping is usefully employed in conjunction with preparatory-scale GC analysis.
Cryogenic methods – those that employ cryogenic fluids/gases but also other approaches to generate reduced temperature – are versatile, functional and relatively easily implemented as part of a total gas chromatographic method. The general utility of a cold region is almost invariably as a trapping or focussing step, to collect analyte into a sharp zone. The success in effectively trapping analyte depends on analyte volatility and the temperature of the cold region. Analytes collection into a sorbent phase supported by cryotrapping usually provide a greater capacity trapping for the sorption step. Stripping analyte from a sample into a cryogenic trap, with subsequent introduction to GC as in a purge-and-trap method, sample introduction into an injector with incorporation of a cooling zone, manipulation and management of chromatographic bands during chromatography elution such as employed in multidimensional gas chromatography, and focussing analyte just prior to the detector, all have the same goal of concentrating the band, reducing its dispersion, and maximising response. This review summarises various approaches that demonstrate how cryogenic methods have been incorporated into gas chromatographic analysis.
Polyphenols are a class of plant secondary metabolites that are recently drawing a special interest because of their broad spectrum of pharmacological effects. As they are characterized by an ...enormous structural variability, the identification of these molecules in food samples is a difficult task, and sometimes having only a limited number of commercially available reference materials is not of great help. One‐dimensional liquid chromatography is the most widely applied analytical approach for their analysis. In particular, the hyphenation of liquid chromatography to mass spectrometry has come to play an influential role by allowing relatively fast tentative identification and accurate quantification of polyphenolic compounds at trace levels in vegetable media. However, when dealing with very complex real‐world food samples, a single separation system often does not provide sufficient resolving power for attaining rewarding results. Comprehensive two‐dimensional liquid chromatography is a technique of great analytical impact, since it offers much higher peak capacities than separations in a single dimension. In the present review, we describe applications in the field of comprehensive two‐dimensional liquid chromatography for polyphenol analysis in real‐world food samples. Comprehensive two‐dimensional liquid chromatography applications to nonfood matrices fall outside the scope of the current report and will not be discussed.
Metabolic profiling of Glycyrrhiza glabra using comprehensive two‐dimensional liquid chromatography (LC × LC) coupled with photodiode array (PDA) and mass spectrometry (MS) detection is described. ...The separation was conducted under reversed‐phase conditions, using a combination of first dimension (1D) 150 mm microbore cyano column utilising 2.7 μm diameter (dp) particles, and second dimension (2D) 50 mm superficially porous octadecylsilica column with 2.7 μm dp particles. A multi‐segmented shift gradient (MSG) for the 2D separation was developed, and the orthogonality achieved was compared with other modes of gradients, such as full in‐fraction, and shift gradient systems. Results demonstrated a significant expansion of metabolic coverage using MSG in 2D, providing the highest measure of orthogonality compared to other gradient modes. Compound identifications were performed by employing complementary data from PDA and MS detection, with reference to structural group‐type distribution in 2D space. A total of ca. 120 compounds were detected, and among them 37 were tentatively identified, distributed over the chemical families of glycosylated flavanones, triterpene saponins, and others. In comparison with one‐dimensional LC, the total number of compounds detected was ca. 2‐fold greater when LC × LC was employed. To the best of our knowledge, this is the first demonstration of the MSG mode in LC × LC, representing a powerful strategy to expand the metabolic coverage for analysis of plant‐derived extracts, containing a multitude of different phytochemical classes.
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Cafestol and kahweol (C&K) are natural coffee diterpenes with high commercial value. There is thus interest in their synthesis although their isolation from natural products remains ...an alternative to recovering high quantities of C&K. The present work aimed at developing an isolation procedure to obtain C&K for both analytical purposes and in gram-scale from coffee beans. The procedure was divided into three steps: an initial saponification reaction optimized by Factorial Design, a choice of solvent for extraction of a crude C&K mixture based on Hansen Solubility Parameters, and a subsequent purification by column chromatography and preparative liquid chromatography in recycling mode to improve C&K mixture purity and for separate preparative collection of each diterpene. The first two steps are useful to maximize yield for C&K quantification, and the complete procedure allowed isolation of 1.5 g of C&K per 300 g of green coffee beans. This isolation procedure can be repeated 25 times using ca. US$1k in reagents, with an estimated value of product varying from US$227k to US$322k for a diterpene mass of 37.5 g, at the prevailing commercial rate.
A novel dynamic approach is described to profile volatile organic compound (VOC) and semi-VOC (SVOC) emission during coffee roasting aimed at analysing components present in the roasting plume, and ...to monitor their evolution during the process. Two sorbents – coconut shell charcoal (CSC) and styrene-divinylbenzene resin (XAD-2) – were evaluated while collecting substances in four sequential time intervals (0–3, 3–6, 6–9 and 9–12 min). Extracted VOCs (<200 Da) and SVOCs were analysed by gas chromatography (GC), and comprehensive two-dimensional gas chromatography (GC × GC) with flame ionisation (FID) and time-of-flight mass spectrometry (TOFMS) detection. Results showed CSC extraction presented poor recovery of VOCs and SVOCs released during roasting. However, XAD-2 was able to collect both groups, including SVOCs of >400 Da. GC × GC resolved many co-eluting compounds observed in 1D GC and allowed chemical group type cluster analysis, revealing that many non-polar VOCs are observed within the 0–3 min interval, and that the release of polar and higher molar mass SVOCs were mostly found within the 3–6 min interval. These group-type cluster analyses offer a broad spectrum chemical profile of the released substances. It may also reveal detailed insights into the roast process evolution over time.
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•Dynamic analysis of coffee VOC and SVOC release tracks roasting evolution.•SVOCs such as fatty acids, caffeine and sterols are released after coffee bean cracking.•Styrene-divinylbenzene resin (XAD-2) was used to trap SVOCs of >400 Da.•GC × GC resolved many closely-eluting 1D GC compounds, allowing group type analysis.
•Raw coffee bean extract lipids were analysed using GC×GC, without derivatisation.•Classes included fatty acids, diterpenes, tocopherols, sterols, DAGs and TAGs.•The latter late eluting analytes ...required high temperature GC analysis.•Cafestol and kahweol ester series were tentatively identified.•Normal hydrocarbons and DAGs were indicated as common coffee oil components.
Comprehensive two-dimensional gas chromatography (GC×GC) approaches with cryogenic modulation were developed for the qualitative analysis of selected low volatility compounds in raw coffee bean extracts, without derivatisation. The approaches employed short first (1D) and second (2D) dimension columns, specifically a 1D 65% phenyl methyl siloxane column (11m) and a 2D 5% phenyl methyl siloxane column (1m), which allowed elution of high molar mass compounds (e.g.>600Da). Solutes included hydrocarbons, fatty acids, diterpenes, tocopherols, sterols, diterpene esters, and di- and triacylglycerides. An oven temperature program up to 370°C was employed. The effects of experimental conditions were investigated, revealing that the GC×GC results strongly depended on the cryogenic trap T, and oven T program. An appropriate condition was selected and further applied for group type analysis of low volatility compounds in green Arabica coffee beans. Retention indices were compiled for 1D GC analysis and were similar for the composite column data in GC×GC. The elution of some compounds was confirmed by use of authentic standards. The approach allowed direct analysis of coffee extract in ethyl acetate solution, with improved analyte peak capacity (approximately 200 compounds were detected) without prior fractionation or pre-treatment of the sample. This avoided potential hydrolysis of high molar mass conjugate esters as well as degradation of thermally labile compounds such as the derivatives of the diterpenes cafestol and kahweol.
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