Five commercial ionic liquid (IL) columns have been evaluated for the first time for the gas chromatography-mass spectrometry (GC-MS) analysis of low molecular weight carbohydrate (LMWC) standards (mono-, di-, and trisaccharides, inositols, and iminosugars). A previous derivatization step was necessary to convert the LMWCs into their volatile and stable derivatives. Compared with conventional GC stationary phases, such as HP-1 and Supelcowax® 10, IL columns have shown a different selectivity in the separation of target compounds. Among the IL columns, only SLB™-IL82 allowed the elution of all the LMWCs studied. Its performance in terms of peak width and asymmetry, evaluated under different oven temperature conditions, was shown to be dependent on the carbohydrate class considered. As an example of application, a SLB™-IL82 column was successfully used to separate the complex mixtures of LMWCs in hyacinth and mulberry extracts. This column is an interesting alternative to the conventional stationary phases used in the GC analysis of LMWCs in real-world samples. [Figure not available: see fulltext.]. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.

Novel methodologies for the improved extraction of bioactive carbohydrates that fulfill the principles of green chemistry have been reviewed in this manuscript. As an alternative to conventional water extraction methods, advantages of the use of new green solvents such as ionic liquids and deep eutectic solvents have been discussed. Recent applications of advanced techniques such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE) and enzyme-assisted extraction (EAE) have also been revised. Special attention has been paid to those procedures based on the combination of several of these techniques which provide a better performance [e.g. ultrasound-microwave-assisted extraction (UMAE)] or show an improved selectivity [e.g. microwave-assisted aqueous two-phase extraction (MAATPE), microwave-assisted enzymatic extraction or enzymolysis-ultrasound-assisted extraction (MAEE or EUAE), etc.]. Finally, future perspectives regarding the possible application of these new eco-friendly methodologies at industrial scale together with the advances required to that aim are presented. © 2019 Elsevier B.V.

An extensive characterization of low molecular weight carbohydrates (LMWC) and phenylalkanoid glycosides (PAG) of Sedum roseum root supplements has been carried out for the first time by gas chromatography coupled to mass spectrometry (GC–MS) and by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-ToF MS). Optimization of the required derivatization procedure for improved determination of PAG showed the combined use of trimethylsilylimidazole and trimethylchlorosilane as the most appropriate reagents. Up to 37 compounds were qualitative- and quantitatively characterized in different dietary supplements of S. roseum by GC–MS. In addition to the well-known rosin, rosarin, rosavin and salidroside, other carbohydrates, polyalcohols, acids, etc. were determined. Among them, several seven-carbon monosaccharides such as coriose and 2,7-anhydro-β-D-altro-heptulose were detected for the first time in S. roseum root supplements. Sedoheptulose was found to be the most abundant compound (9–151 mg g−1), followed by rosiridin (20–81 mg g−1) and rosavin (11–56 mg g−1). The use of GC × GC-ToF MS allowed the detection and tentative assignation of 48 additional compounds mainly belonging to the phenylalkanoid glycoside, pentosyl-hexose and hexosyl-hexose families. © 2018 Elsevier B.V.

Characterization of the volatile composition by analytical techniques usually requires the previous isolation, and occasionally the concentration, of these compounds. For these purposes, headspace (HS) techniques, both static headspace (S-HS) and dynamic headspace (D-HS), are usually considered. HS techniques are commonly coupled to gas chromatography; however, the direct coupling to mass spectrometry, without prior separations systems, is an operation mode that is gaining popularity for the development of fast and economic methods of analysis. In this chapter, fundamentals and instrumentation of HS sampling are described and the specific parameters that need to be optimized before applying an HS method are also discussed. Special emphasis has been put in covering the most relevant advances of these techniques, discussing specific examples of the most extended applications regarding food, environmental and pharmaceutical analysis. © 2017 Elsevier B.V.

Pressurized liquid extraction of Aglaonema sp. iminosugars has been optimized. A single cycle under optimal conditions (80 mg, 100 °C, 2 min) was enough to extract ≥96\% of most iminosugars. Further incubation with Saccharomyces cerevisiae for 5 h removed coextracted interfering low molecular weight carbohydrates from extracts of different Aglaonema cultivars. A complete characterization of these extracts was carried out by gas chromatography-mass spectrometry: three iminosugars were tentatively identified for the first time; α-homonojirimycin and 2,5-dideoxy-2,5-imino-d-mannitol were the major iminosugars determined. α-Glucosidase inhibition activity, cell viability and thermal stability of Aglaonema extracts were also evaluated. Extracts with IC50 for α-glucosidase activity in the 0.010-0.079 mg mL-1 range showed no decrease of Caco-2 cell viability at concentrations lower than 125 μg mL-1 and were stable at 50 °C for 30 days. These results highlight the potential of Aglaonema extracts as a source of bioactives to be used as functional ingredients. © 2016 Elsevier Ltd. All rights reserved.

Although qualitative strategies based on direct injection mass spectrometry (DiMS) have recently emerged as an alternative for the rapid classification of food samples, the potential of these approaches in quantitative tasks has scarcely been addressed to date. In this paper, the applicability of different multivariate regression procedures to data collected by DiMS from simulated mixtures has been evaluated. The most relevant factors affecting quantitation, such as random noise, the number of calibration samples, type of validation, mixture complexity and similarity of mass spectra, were also considered and comprehensively discussed. Based on the conclusions drawn from simulated data, and as an example of application, experimental mass spectral fingerprints collected by direct thermal desorption coupled to mass spectrometry were used for the quantitation of major volatiles in Thymus zygis subsp. zygis chemotypes. The results obtained, validated with the direct thermal desorption coupled to gas chromatography-mass spectrometry method here used as a reference, show the potential of DiMS approaches for the fast and precise quantitative profiling of volatiles in foods. © 2016 The Author(s) Published by the Royal Society. All rights reserved.

A method by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry (HILIC-MS2) has been successfully developed for the simultaneous analysis of bioactive iminosugars and other low molecular weight carbohydrates in Aglaonema leaf extracts. Among other experimental chromatographic conditions, mobile phase eluents, additives and column temperature were evaluated in terms of retention time, resolution, peak width and symmetry provided for target carbohydrates. In general, narrow peaks (wh: 0.2-0.6min) with good symmetry (As: 0.9-1.3) and excellent resolution (Rs>1.8) were obtained for iminosugars using an acetonitrile:water gradient with 5mM ammonium acetate in both eluents at 55°C. Tandem mass spectra were used to confirm the presence of previously detected iminosugars in Aglaonema extracts and to tentatively identify for the first time others such as miglitol isomer, glycosyl-miglitol isomers and glycosyl-DMDP isomers. Concentration of total iminosugars varied from 1.35 to 2.84mgg-1 in the extracts of the different Aglaonema samples analyzed. To the best of our knowledge, this is the first time that a HILIC-MS2 method has been proposed for the simultaneous analysis of iminosugars and other low molecular weight carbohydrates of Aglaonema sp. extracts. © 2015 Elsevier B.V.

In the present work, the influence of power ultrasound (US) on the quality of fruits and vegetables during both the pre-treatment and drying has been evaluated. Chemical indicators such as pectinmethyl esterase and peroxidase enzymes, vitamin C, carbohydrates, proteins, polyphenols and 2-furoylmethylamino acids (indicators of the early stages of Maillard reaction) have been studied. In addition, rehydration capacity, leaching losses and shrinkage and organoleptic characteristics of the final product have also been assessed. During blanching, similar leaching losses and enzyme inactivation were found in low temperature and prolonged conventional treatments and in US processes, but with a significant reduction in the time for the latter. Finally, application of US in drying of carrots and strawberries originated significant reductions in processing time, while providing high quality end-products. The quality was higher as compared to marketed products and superior or equivalent to samples obtained under similar conditions in a prototype convective dryer, and, in the case of some indicators, similar to that of freeze-dried samples. © 2015 The Authors.

A Solid-Phase Microextraction method for the Gas Chromatography-Mass Spectrometry analysis of blackberry (Rubus sp.) volatiles has been fully optimized by means of a Box-Behnken experimental design. The optimized operating conditions (Carboxen/Polydimethylsiloxane fiber coating, 66 °C, 20 min equilibrium time and 16 min extraction time) have been applied to the characterization for the first time of the volatile composition of Rubus ulmifolius Schott blackberries collected in Italy and Spain. A total of 74 volatiles of different functionality were identified; esters and aliphatic alcohols were the predominant classes in both sample types. Methylbutanal (2.02-25.70\%), ethanol (9.84-68.21\%), 2,3-butanedione (2.31-14.71\%), trans-2-hexenal (0.49-17.49\%), 3-hydroxy-2-butanone (0.08-7.39\%), 1-hexanol (0.56-16.39\%), 1-octanol (0.49-10.86\%) and methylbutanoic acid (0.53-21.48\%) were the major compounds in most blackberries analyzed. Stepwise multiple regression analysis of semiquantitative data showed that only two variables (ethyl decanoate and ethyl acetate) were necessary for a successful differentiation of blackberries according to their harvest location. © 2015 Elsevier Ltd.

We review the use of static headspace (S-HS) and dynamic headspace (D-HS) techniques for the extraction of volatiles from different matrices. We present fundamentals and the most relevant advances in instrumentation, together with detailed discussion on the most important parameters affecting HS sampling. We also describe some of the most recent and outstanding applications, classified according to the type of matrix - among them, the use of ionic liquids as solvents for S-HS, the coupling of D-HS to comprehensive two-dimensional gas chromatography, the development of novel miniaturized devices for D-HS sampling and increasing interest in approaches based on HS-mass spectrometry (HS-MS) for fast, unbiased sample classification. We also review multi-step strategies for accurate quantitation of volatiles in samples with noticeable matrix effects. To conclude, we show that HS sampling is a versatile, rapid, efficient, green technique for volatile extraction, free of interferences. © 2015 Elsevier B.V..

A combination of gas chromatographic retention data (linear retention indices) on two different stationary phases (100\% methyl- and 50\% phenylmethylsilicone) and electron impact mass spectrometric relative abundances for characteristic m/z ratios of 12 trimethylsilylated piperidine and pyrrolidine iminosugars are reported. These results have been related to their structural features and applied to the characterization of iminosugar composition of an Aglaonema treubii root extract. Seven iminosugars were detected in this extract, two of them were described for the first time. © 2014 Elsevier B.V.

Statistical analysis has been used for the first time to evaluate the dispersion of quantitative data in the solid-phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis of blackberry (Rubus ulmifolius Schott) volatiles with the aim of improving their precision. Experimental and randomly simulated data were compared using different statistical parameters (correlation coefficients, Principal Component Analysis loadings and eigenvalues). Non-random factors were shown to significantly contribute to total dispersion; groups of volatile compounds could be associated with these factors. A significant improvement of precision was achieved when considering percent concentration ratios, rather than percent values, among those blackberry volatiles with a similar dispersion behavior. As novelty over previous references, and to complement this main objective, the presence of non-random dispersion trends in data from simple blackberry model systems was evidenced. Although the influence of the type of matrix on data precision was proved, the possibility of a better understanding of the dispersion patterns in real samples was not possible from model systems. The approach here used was validated for the first time through the multicomponent characterization of Italian blackberries from different harvest years. © 2014 Elsevier B.V.

Physical and chemical quality parameters (dry matter, aw, protein, carbohydrates, vitamin C, 2-furoylmethyl amino acids, rehydration ratio and leaching loss) have been determined in 30 commercial dehydrated fruits (strawberry, blueberry, raspberry, cranberry, cherry, apple, grapefruit, mango, kiwifruit, pineapple, melon, coconut, banana and papaya). For comparison purposes, strawberry samples processed in the laboratory by freeze-drying and by convective drying were used as control samples. Overall quality of dehydrated fruits seemed to be greatly dependent on processing conditions and, in a cluster analysis, samples which were presumably subjected to osmotic dehydration were separated from the rest of fruits. These samples presented the lowest concentration of vitamin C and the highest evolution of Maillard reaction, as evidenced by its high concentration of 2-furoylmethyl amino acids. This is the first study on the usefulness of this combination of chemical and physical indicators to assess the overall quality of commercial dehydrated fruits. © 2013 Elsevier Ltd. All rights reserved.

In this paper, a study on the usefulness of the determination of vitamin C together with indicators of the initial steps of Maillard reaction (2-furoylmethyl amino acids, 2-FM-AA) during the convective drying of strawberries has been carried out for the first time, paying special attention to the kinetics of degradation and formation, respectively, of both parameters. Formation of 2-FM-AA of Lys, Arg and GABA and vitamin C loss increased with time and temperature following, respectively, a zero and first-order kinetics. As supported by its lower activation energy, 2-FM-GABA (55.9 kJ/mol) and 2-FM-Lys + 2-FM-Arg (58.2 kJ/mol) were shown to be slightly more sensitive indicators than vitamin C (82.1 kJ/mol). The obtained results, together with a complementary study on the rehydration ability and sensorial attributes of samples, pointed out the suitability of the convective drying system to obtain dried strawberries of high nutritive quality and bioactivity and good consumer acceptance. © 2013 Elsevier Ltd. All rights reserved.

A study on the quality parameters of strawberries dehydrated by convection assisted by power ultrasound (US) at 40-70 °C and 30 and 60 W has been carried out for the first time. In general, the quality of US-treated samples was higher than that of commercial samples. Even under the most severe conditions used (US at 70 °C and 60 W), high values of vitamin C retention (>65\%) and scarce advance of Maillard reaction (2-furoylmethyl derivatives of Lys and Arg < 90 mg 100 g-1 protein) were observed. Rehydration ratio was not affected by the power applied and the obtained values were similar to those of convectively-treated samples. According to the results here presented, US is a suitable example of an emerging and environmentally friendly technology that accelerates convective drying, allowing the obtainment of dried strawberries with premium quality. © 2014 Elsevier Ltd. All rights reserved.

Iminosugars are considered potential drug candidates for the treatment of several diseases, mainly as a result of their α-glycosidase inhibition properties. A method by hydrophilic interaction liquid chromatography tandem mass spectrometry has been optimized for the first time for the simultaneous determination of complex mixtures of bioactive iminosugars and other low molecular weight carbohydrates (LMWC) in vegetable extracts. Three hydrophilic stationary phases (sulfoalkylbetaine zwitterionic, polyhydroxyethyl aspartamide and ethylene bridge hybrid (BEH) with trifunctionally bonded amide) were compared under both basic and acidic conditions. The best sensitivity (limits of detection between 0.025 and 0.28 ng mL-1) and overall chromatographic performance in terms of resolution, peak width and analysis time were obtained with the BEH amide column using 0.1\% ammonium hydroxide as a mobile phase additive. The optimized method was applied to the analysis of extracts of hyacinth bulbs, buckwheat seeds and mulberry leaves. Iminosugar and other LMWC structures were tentatively assigned by their high resolution daughter ions mass spectra. Several iminosugars such as glycosyl-fagomine in mulberry extract were also described for the first time. Among the extracts analysed, mulberry showed the widest diversity of iminosugars, whereas the highest content of them was found in hyacinth bulb (2.5 mg g-1) followed by mulberry (1.95 mg g-1). © 2014 Elsevier B.V.

For the first time, four commercial ionic liquid columns (SLB-IL59, SLB-IL76, SLB-IL82 and SLB-IL100) for gas chromatography have been comprehensively evaluated in terms of efficiency, polarity and solvation properties. Grob tests and McReynolds constants showed that they were all high-efficiency columns of high polarity, but with low inertness to compounds with hydrogen bonding capabilities. The solvation parameter model was used to characterize the solvation interactions of the four columns in the 80-160. °C temperature range. Results revealed that all the ionic liquids studied can be considered moderately hydrogen-bond acid and highly cohesive stationary phases, on which the dominant contributions to retention were the dipolar-type and hydrogen-bond base interactions, while π- π and n- π interactions were barely significant. The SLB-IL59 column provided the best separation of homologs, while the SLB-IL76 and SLB-IL100 columns had the most basic and the most acidic phases, respectively. A principal component analysis for the commonly used stationary phases in capillary GC showed that these commercial ionic liquid columns fill an empty area of the available selectivity space, which clearly enhances the separation capacity of this technique. © 2013 Elsevier B.V.

Sample preparation, equipment, and several outstanding applications using gas chromatography (GC) to analyze bioactive food oligosaccharides are described and discussed. In addition to basic operations for sample pretreatment, chemical procedures such as derivatization (for the direct analysis of oligosaccharides) and hydrolysis and methylation (for their structural characterization) are described in detail. Simultaneous pyrolysis and derivatization (thermochemolysis) are also reported for GC characterization of oligosaccharides. Advances in GC such as the use of high-temperature columns to analyse oligosaccharides with a degree of polymerization of up to 11 and mass spectrometry detectors for better identification/characterization of unidentified compounds are also described. Finally, the potential of the recently developed Comprehensive Two-Dimensional Gas Chromatography technique to separate complex carbohydrate mixtures is discussed. © 2014 by JohnWiley & Sons, Ltd. All rights reserved.

This study was conducted to determine the mechanisms implicated in the beneficial effects of apple polyphenols (APs) against diet-induced obesity in Wistar rats, described in a previous study from our group. Supplementation of high-fat sucrose diet with AP prevented adiposity increase by inhibition of adipocyte hypertrophy. Rats supplemented with AP exhibited improved glucose tolerance while adipocytes isolated from these rats showed an enhanced lipolytic response to isoproterenol. AP intake led to reduced Lep, Plin, and sterol regulatory element binding transcription factor 1 (Srebf1) mRNA levels and increased aquaporin 7 (Aqp7), adipocyte enhancer binding protein 1 (Aebp1), and peroxisome proliferator-activated receptor gamma co-activator 1 alpha (Ppargc1a) mRNA levels in epididymal adipocytes. In addition, we found different methylation patterns of Aqp7, Lep, Ppargc1a, and Srebf1 promoters in adipocytes from apple-supplemented rats compared to high-fat sucrose fed rats. The administration of AP protects against body weight gain and fat deposition and improves glucose tolerance in rats. We propose that AP exerts the antiobesity effects through the regulation of genes involved in adipogenesis, lipolysis, and fatty acid oxidation, in a process that could be mediated in part by epigenetic mechanisms. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

BACKGROUND: Currently, disorders such as diabetes mellitus, obesity or atherosclerosis are recognised as major global health problems. The use of inositols for treating these illnesses has attracted considerable attention and their extraction from natural sources presents added value as they are considered bioactive ingredients in the food industry. Legumes are natural and rich sources of inositols; however, the co-existence of other low molecular weight carbohydrates (LMWCs) in their extracts, which interfere in their bioactivity, might constitute an important drawback, thereby making their removal essential. RESULTS: LMWCs, including inositols, methyl-inositols and glycosyl-inositols of different legume extracts, were determined by GC-MS; the presence of bornesitol (2.35 mg g-1) and lathyritol (0.27 mg g-1) were reported for the first time in grass peas. The use of Saccharomyces cerevisiae for the selective removal of interfering carbohydrates was optimised. Incubation time (3-40 h) was highly dependent on the composition of the legume considered; inositol contents were generally stable along the treatment. CONCLUSION: Removal of interfering LMWCs from inositol-enriched extracts was successfully achieved using a clean and easily scalable fractionation methodology. This biotechnological procedure not only represents high interest for the production of bioactive food ingredients but for applications in other research areas. © 2013 Society of Chemical Industry.