RESUMEN
Chia seed (Salvia hispanica L.) is a food rich in protein, fiber, polyunsaturated fatty acids and antioxidants. Consequently, its incorporation in food formulations may be desirable from a nutritional and healthy point of view. However, there is concern regarding the formation of process contaminants when they are subjected to thermal processing. The objective of this study was to incorporate different amounts of ground chia seeds in a biscuit model to evaluate the effect on the antioxidant capacity and formation of acrylamide and furfurals. Seven standard "Maria-type" biscuit formulations were prepared, replacing wheat flour with different amounts of ground chia seeds (defatted and non-defatted), from 0% (control biscuit) to 15% (respect to total solids in the recipe). Samples were baked at 180 °C for 22 min. Compared with the control biscuit, chia formulations increased the content of nutrients, antioxidant capacity (ABTS) and phenolic compounds (Folin-Ciocalteau method) but also doubled acrylamide levels and even raised more than 10 times furanic compound concentrations. Results indicate that the use of chia seeds as ingredients in new cereal-based formulations would improve the nutritional profile but also increase the occurrence of chemical process contaminants. This paradox should be carefully considered in the context of risk/benefit analysis.
Asunto(s)
Antioxidantes , Grano Comestible , Grano Comestible/química , Antioxidantes/química , Harina/análisis , Triticum , Semillas/química , Acrilamidas/análisisRESUMEN
There is an increasing interest in determining the concentration of furanic compounds naturally formed in food aqueous matrices, by in situ, fast and low-cost methods. A sensor presenting such characteristics is here proposed, and characterized. It is based on a molecularly imprinted polymer (MIP) as a receptor with electrochemical transduction on a screen printed cell (SPC). The molecularly imprinted polymer has been developed for a particular furanic derivative, 2-furaldehyde (2-FAL). The detection bases on the reduction of 2-FAL selectively adsorbed on the polymer layer in contact with the working electrode. The polymer layer is simply formed by in situ polymerization, directly over the SPC and it was characterized by IR, SEM and electrochemical methods. Even if based on an easy and fast preparation procedure, the layer sufficiently adheres to the cell surface giving a reusable sensor. Square wave voltammetry (SWV) was applied as the signal acquisition method. The sensor performance in aqueous solution (NaCl 0.1 M) was tested, obtaining that the dose-response curve is fitted by the Langmuir adsorption isotherm. The sensitivity, and so the limit of detection, were noticeably improved by a chemometric approach based on the Design of experiment method. (optimized conditions: Estep = 0.03 V, Epulse = 0.066 V, f = 31 s-1). In water solution at pH around neutrality the dynamic range was from about 50 µM to 20 mM. Similar results were obtained for a white wine containing 12% ethanol, which has been considered as a typical example of beverage possibly containing furhaldehydes. The higher limit of quantification can be modulated by the amount of MIP deposited, while the lower detection limit by the conditions of the electrochemical measurement.
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Impresión Molecular , Bebidas , Técnicas Electroquímicas , Electrodos , Furaldehído , Límite de Detección , Polímeros Impresos MolecularmenteRESUMEN
Non-centrifugal cane sugar (panela) is an unrefined sugar obtained through intense dehydration of sugarcane juice. Browning, antioxidant capacity (measured by ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assay and total phenolic content) and the formation of acrylamide and other heat-induced compounds such as hydroxymethylfurfural (HMF) and furfural, were evaluated at different stages during the production of block panela. Values ranged between below the limit of quantitation (LOQ)-890 µg/kg, < LOQ-2.37 mg/kg, < LOQ-4.5 mg/kg, 0.51-3.6 Abs 420 nm/g, 0.89-4.18 mg gallic acid equivalents (GAE)/g and 5.08-29.70 µmol TE/g, for acrylamide, HMF, furfural, browning, total phenolic content and ABTS (all data in fresh weight), respectively. Acrylamide significantly increased as soluble solid content increased throughout the process. The critical stages for the formation of acrylamide, HMF and furfural were the concentration of the clarified juice in the concentration stage to get the panela honey and the final stage. Similar trends were observed for the other parameters. This research concludes that acrylamide, HMF and furfural form at a high rate during panela processing at the stage of juice concentration by intense evaporation. Therefore, the juice concentration stage is revealed as the critical step in the process to settle mitigation strategies.
RESUMEN
A total of 42 different rums currently marketed in Spain were analyzed to study the effect of aging time and manufacturing steps (filtration, addition of additives or spices, solera aging method, use of different types of aging barrels) on several parameters: color, non-enzymatic browning, antioxidant capacity and phenolic profile. Different analytical techniques to obtain a broader descriptions of the samples were employed: absorption and UV-vis spectrophotometry, antioxidant capacity (DPPH, FRAP, ABTS methods), total phenols and HPLC to detect individual phenolic and furanic compounds. Results showed that spectrophotometric techniques could potentially be used to detect adulteration and frauds, as well as to differentiate rums by aging time. Those rums aged longer, especially those aged in oak barrels that had previously contained Bourbon or wine, showed higher phenolic content, antioxidant capacity and concentration of furanic compounds. Filtration results in the loss of antioxidant compounds while adding spices increases their concentration in rums.
RESUMEN
Carbonyl compounds and furan derivatives may form adducts with DNA and cause oxidative stress to human cells, which establishes the carcinogenic potential of these compounds. The occurrence of these compounds may vary according to the processing characteristics of the beer. The objective of this study was, for the first time, to investigate the free forms of target carbonyl compounds [acetaldehyde, acrolein, ethyl carbamate (EC) and formaldehyde] and furan derivatives [furfural and furfuryl alcohol (FA)] during the brewing stages of ale and lager craft beers. Samples were evaluated using headspace-solid phase microextraction and gas chromatography with mass spectrometric detection in selected ion monitoring mode (HS-SPME-GC/MS-SIM). Acetaldehyde, acrolein, formaldehyde and furfuryl alcohol were found in all brewing stages of both beer types, while EC and furfural concentrations were below the LOD and LOQ of the method (0.1 and 0.01 µg L-1, respectively). Boiling and fermentation of ale brewing seem to be important steps for the formation of acrolein and acetaldehyde, respectively, while boiling resulted in an increase of FA in both types of beer. Conversely, pasteurisation and maturation reduced the levels of these compounds in both types of beer. An increase in concentration of acrolein has not been verified in lager brew probably due to the difference in boiling time between these two types of beer (60 and 90 min for ale and lager, respectively).
Asunto(s)
Cerveza/análisis , Análisis de los Alimentos , Contaminación de Alimentos/análisis , Acetaldehído/efectos adversos , Acetaldehído/análisis , Acroleína/efectos adversos , Acroleína/análisis , Cerveza/efectos adversos , Fermentación , Formaldehído/efectos adversos , Formaldehído/análisis , Furanos/efectos adversos , Furanos/análisis , Humanos , Uretano/efectos adversos , Uretano/análisisRESUMEN
Compounds with toxic potential may occur in beer, such as carbonyl compounds (acetaldehyde, acrolein, ethyl carbamate [EC] and formaldehyde) and furan derivatives [furfural and furfuryl alcohol (FA)]. The objective of this study was, for the first time, to validate a method based on headspace-solid phase microextraction using a PDMS-overcoated fibre and gas chromatography with mass spectrometric detection in selected ion monitoring mode (HS-SPME-GC/MS-SIM) to investigate target carbonyl compounds and furan derivatives in beers. Analytical curves showed proper linearity with r2 ranging from 0.9731 to 0.9960 for acetaldehyde and EC, respectively. The lowest LOD was found for acetaldehyde (0.03 µg L-1), while the lowest LOQ value (1.0 µg L-1) was found for acetaldehyde and EC, formaldehyde and furfural. Recovery (90% to 105%), intermediate precision and repeatability (lower than 13%), limits of detection and quantification (values below 2.5 µg L-1) showed that the method is suitable to simultaneously quantify these compounds. EC was detected in only two samples (1 lager and 1 ale). Furfural was found in 37% and 82% of ale and lager beers, respectively. Acetaldehyde, acrolein, formaldehyde and FA were detected in all samples. However, acrolein was the only compound found in the commercial samples at a concentration capable of causing health risk. Besides furfural and FA, four other furan-containing compounds (5-methyl-2-furan methanethiol, acetylfuran, 5-methylfurfural and γ-nonalactone) were also found in beers, however, at levels low enough not to impose potential health risk.
Asunto(s)
Cerveza/análisis , Contaminación de Alimentos/análisis , Microextracción en Fase Sólida , Acetaldehído/análisis , Acroleína/análisis , Formaldehído/análisis , Furanos/análisis , Cromatografía de Gases y Espectrometría de Masas , Estructura Molecular , Medición de Riesgo , Uretano/análisisRESUMEN
One of the possibilities of limiting carbon dioxide emissions is to use pyrolysis oils from biomass. However, their very high oxygen content confers to these oils a chemical instability and a high viscosity. Among the oxygen-containing compounds present in bio-oils, furanic compounds derived from the decomposition of cellulosic and hemi-cellulosic biomass are the most refractory to deoxygenation. The major products of their hydrodeoxygenation are alkanes and secondly alkenes, but the intermediates are still subject to controversy. In this work, we performed a DFT simulation of the hydrodeoxygenation of furan (C4H4O) and 2-methylfuran in the presence of molybdenum and tungsten sulphide Mo(W)S2. The aim of this work is to elucidate the reaction intermediates and to compare the activities of the two catalytic sites used in our reaction conditions. Our calculations show that the partial hydrogenation of the two molecules occurs preferentially in position (2,5). The hydrogenolysis reactions of the C-O bonds occur in two steps. The molybdenum sulphide exhibits higher catalytic activity.
RESUMEN
Dwindling fossil fuel resources and substantial release of CO2 from their processing have increased the appeal to use biomass as a sustainable platform for synthesis of chemicals and fuels. Steps toward this will require selective upgrading of biomass to suitable intermediates. Traditionally, biomass upgrading has involved thermochemical processes that require excessive amounts of petrochemical-derived H2 and suffer from poor product selectivity. Electrochemical routes have emerged as promising alternatives because of (a) the replacement of petrochemical-derived H2 by protons generated in situ, (b) mild operating temperatures and pressures, and (c) the use of electrode potential to tune reaction rates and product selectivity. In this review, we highlight the advances in the electrocatalytic hydrogenation and oxidation of biomass-derived platform molecules. The effects of important reaction parameters on electrochemical efficiency and catalytic activity/selectivity are thoroughly discussed. We conclude by summarizing current challenges and discussing future research directions.
Asunto(s)
Biomasa , Técnicas Electroquímicas/métodos , Oxígeno/química , Catálisis , Hidrogenación , Oxidación-Reducción , ProtonesRESUMEN
BACKGROUND: The production of the traditional carob liquor from Algarve (Portugal) depends on numerous factors such as carob processing, variety and maceration conditions. An experimental design with 36 runs was created to evaluate the effect of the roasting temperature, particle size, variety of carob and time of maceration on several parameters of carob liquors as gallic acid and total phenolic content, the furanic composition (furfural and 5-(hydroxymethyl)furfural), browning index and in vitro antioxidant capacity. RESULTS: The results revealed that carob variety was the independent variable with the greatest effect on antioxidant capacity, total phenolic and gallic acid content. In particular, AIDA liquors presented the highest results, mainly those prepared with unroasted carob. Meanwhile, Galhosa and Mulata liquors showed the greatest concentrations when the carob pulp was roasted at 150 °C. The furanic composition and browning index were greatly influenced by the carob roasting degree. CONCLUSION: The levels of the main toxic furanics present in carob liquors, furfural and 5-(hydroxymethyl)furfural, suggest a safe consumption of these beverages even in samples of carobs with the maximum roasting degree. The smallest carob particle size favoured the highest phenolic extraction, while the longest maceration periods decreased the concentration of the toxic furanic compounds studied. © 2018 Society of Chemical Industry.
Asunto(s)
Antioxidantes/química , Fabaceae/química , Manipulación de Alimentos , Frutas/química , Furanos/química , Fenoles/química , Calor , Factores de TiempoRESUMEN
A wide range of compounds can be formed during thermal processing of food, some of which are relevant for aroma (e.g., furfural), while others are of great health concern (e.g., furan). This paper presents the study of formulation as affecting the simultaneous generation of furan and furfural, along with other aroma quality markers, in sponge cake by means of headspace trap/GC-MS. Ingredients were screened according to their category (fat, salt, sugar, egg-based). Glucose-containing formulation resulted in the highest content of furan and furfural (12.5⯱â¯0.5â¯ngâ¯g-1 and 9.2⯱â¯0.2⯵gâ¯g-1, dry basis, respectively), while their lowest amount was found in the egg-white recipe (3.1⯱â¯0.1â¯ngâ¯g-1 for furan and 0.287⯱â¯0.078⯵gâ¯g-1 for furfural, dry basis). The latter also related negatively to all studied compounds. This work will be useful for developing novel strategies to deliver safe foods with appealing organoleptic attributes.
Asunto(s)
Análisis de los Alimentos , Furanos/análisis , Odorantes/análisis , Contaminación de Alimentos/análisis , Manipulación de Alimentos , Cromatografía de Gases y Espectrometría de Masas , CalorRESUMEN
Biofuranic compounds, typically derived from C5 and C6 carbohydrates, have been extensively studied as promising alternatives to chemicals based on fossil resources. The present work reports the simple assembly of biobased 2,5-furandicarboxylic acid (FDCA) with different metal ions to prepare a range of metal-FDCA hybrids under hydrothermal conditions. The hybrid materials were demonstrated to have porous structure and acid-base bifunctionality. Zr-FDCA-T, in particular, showed a microspheric structure, high thermostability (ca. 400 °C), average pore diameters of approximately 4.7â nm, large density, moderate strength of Lewis-base/acid centers (ca. 1.4â mmol g-1 ), and a small number of Brønsted-acid sites. This material afforded almost quantitative yields of biofuranic alcohols from the corresponding aldehydes under mild conditions through catalytic transfer hydrogenation (CTH). Isotopic 1 Hâ NMR spectroscopy and kinetic studies verified that direct hydride transfer was the dominant pathway and rate-determining step of the CTH. Importantly, the Zr-FDCA-T microspheres could be recycled with no decrease in catalytic performance and little leaching of active sites. Moreover, good yields of C5 (i.e., furfural) or C4 products [i.e., maleic acid and 2(5H)-furanone] could be obtained from furfuryl alcohol without oxidation of the furan ring over these metal-FDCA hybrids. The content and ratio of Lewis-acid/base sites were demonstrated to dominantly affect the catalytic performance of these redox reactions.
Asunto(s)
Ácidos Carboxílicos/química , Furanos/química , Microesferas , Circonio/química , Catálisis , Cinética , Microscopía Electrónica de Transmisión , Oxidación-Reducción , Espectroscopía de Fotoelectrones , Porosidad , Espectroscopía de Protones por Resonancia MagnéticaRESUMEN
A novel microextraction method based on vortex- and CO2 -assisted liquid-liquid microextraction with salt addition for the isolation of furanic compounds (5-hydroxymethyl-2-furaldehyde, 5-methyl-2-furaldehyde, 2-furaldehyde, 3-furaldehyde, 2-furoic and 3-furoic acids) was developed. Purging the sample with CO2 was applied after vortexing to enhance the phase separation and mass transfer of the analytes. The optimum extraction conditions were: extraction solvent (volume), propyl acetate (125 µL); sample pH, 2.4; vortexing time, 45 s; salt concentration, 25% w/v and purging time, 5 min. The analytes were separated using an ODS Hypersil C18 column (250×4.6 mm i.d, 5 µm) under gradient flow. The proposed method showed good linearities (r(2) >0.999), low detection limits (0.08-1.9 µg/L) and good recoveries (80.7-122%). The validated method was successfully applied for the determination of the furanic compounds in concentrated juice (mango, date, orange, pomegranate, roselle, mangosteen and soursop) and dried fruit (prune, date and apricot paste) samples.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Jugos de Frutas y Vegetales/análisis , Frutas/química , Furanos/análisis , Furanos/aislamiento & purificación , Microextracción en Fase Líquida/métodos , Dióxido de Carbono/química , Contaminación de Alimentos/análisis , Límite de Detección , Microextracción en Fase Líquida/instrumentaciónRESUMEN
In this study, the levels of furan, 2-methylfuran, 2,5-dimethylfuran, vinyl furan, 2-methoxymethyl-furan and furfural in different coffee products were evaluated. Simultaneous determination of these six furanic compounds was performed by a head space liquid-phase micro-extraction (HS-LPME) method. A total of 67 coffee powder samples were analysed. The effects of boiling and espresso-making procedures on the levels of furanic compounds were investigated. The results showed that different types of coffee samples contained different concentrations of furanic compounds, due to the various processing conditions such as temperature, degree of roasting and fineness of grind. Among the different coffee samples, the highest level of furan (6320 µg kg⻹) was detected in ground coffee, while coffee-mix samples showed the lowest furan concentration (10 µg kg⻹). Levels in brewed coffees indicated that, except for furfural, brewing by an espresso machine caused significant loss of furanic compounds.