Biochar-MgO from Soursop Seeds in the Production of Biofuel Additive Intermediates.

The conversion of residual biomass from fruit seeds into biochar can be achieved using MgCl2 as an activating agent and calcining at 700 °C. The resulting MgO-biochars were employed in the aldol condensation reaction between furfural and acetone. This reaction is essential as the first step in the obtention of biofuels derived from biomass. The biochars were characterized through various physicochemical techniques, revealing that the presence of MgO nanoparticles deposited on the carbon surface modifies the structural and acidic-basic properties of the carbonaceous materials with a graphitic structure. The biochar with a surface content of MgO of 0.34 % w/w enables the achievement of 100 % of selectivity towards 4-(2-furanyl)-3-buten-2-one (I) with quantitative conversions under optimized conditions. This property highlights the potential of using this type of biochar, commonly used for CO2 capture, as a versatile acidic-basic catalyst, thereby introducing a novel approach to sustainable chemistry.

Transfer Hydrogenation of Furfural to Furfuryl Alcohol Under Microwave Irradiation Using Mixed Oxides.

The reaction to obtain furan alcohols is one of the most important in the upgrading of furan derivates. An attractive route is the transfer hydrogenation of furfural using acidic-basic catalysts. In this work, mixed oxides derived from ternary hydrotalcites were employed to obtain furfuryl alcohol from furfural assisted by microwave irradiation. These materials were characterized via X-ray diffraction (XRD), N2 adsorption-desorption isotherms, Fourier-transform infrared (FTIR) and the CO2 temperature-programmed desorption (CO2 -TPD) analyses. The lamellar structure of hydrotalcite-type materials collapses during the calcination process, resulting in the loss of carbonate anions and hydroxyl groups, present in the interlayer space. This leads to the formation of mixed oxides that exhibit larger surface areas. Furthermore, these changes alter the basic nature of these materials, giving rise to the formation of strong basic sites. The reaction was studied using containing Co2+ and Ni2+ in their structure and was then optimized using distinct primary and secondary alcohols as hydrogen donor sources, as well as distinct temperatures and initial concentrations of furfural. The yields to furfuryl alcohol are strongly dependent on the type of Me2+ in layered oxides mainly due to higher basicity and to the donor employed in the reaction. The mixed oxide containing Co2+ showed complete conversion of furfural and higher yields to furfuryl alcohol (>95 %) at short times of reaction (<1 h).

Determination of 5-hydroxymethylfurfural using an electropolymerized molecularly imprinted polymer in combination with Salle.

Coffee, a beverage with a complex chemical composition, is appreciated for the sensory experience of its taste and aroma. The compound 5-(hydroxymethyl)-2-furfural (HMF) is essential for sensory characterization of the beverage, and is also used in the traceability of its production. In this work, a procedure combining salting-out assisted liquid-liquid extraction (SALLE) and an electropolymerized molecularly imprinted polymer (e-MIP) was developed for the detection and quantification of HMF in coffee samples. The sample preparation step using SALLE employed a combination of acetonitrile and phosphate-buffered saline, in a proportion of 70:30 (ACN:PBS), with addition of 0.02 g of NaCl. The new sensor (e-MIP) was prepared by electropolymerization of p-aminobenzoic acid onto a glassy carbon electrode (GCE) using cyclic voltammetry (CV). Analytical determinations were performed by differential pulse voltammetry (DPV). The linear regression correlation coefficient (r2) for the response was 0.9986. The limits of detection and quantification were 0.372 mg L-1 and 1.240 mg L-1, respectively. The repeatability and reproducibility values obtained were 6 and 10%, respectively. The recoveries for three concentration levels were between 97 and 101%. Analyses of different coffee samples showed that the HMF concentrations varied from 261.0 ± 41.0 to 770.2 ± 55.9 mg kg-1 in powdered coffee samples, and from 1510 ± 50 to 4445 ± 278 mg kg-1 in instant coffee samples. The advantages of this procedure, compared to other methods described in the literature, are its simplicity, easy operation, good selectivity and sensitivity, low cost, and minimal use of organic solvents.

Hydrothermal pretreatment of lignocellulosic biomass for hemicellulose recovery.

The hemicellulosic fraction recovery is of interest for integrated processes in biorefineries, considering the possibility of high economic value products produced from their structural compounds of this polysaccharide. However, to perform an efficient recovery, it is necessary to use biomass fractionation techniques, and hydrothermal pretreatment is highlighted as a valuable technique in the hemicellulose recovery by applying high temperatures and pressure, causing dissolution of the structure. Considering the possibility of this pretreatment technique for current approaches to hemicellulose recovery, this article aimed to explore the relevance of hydrothermal pretreatment techniques (sub and supercritical water) as a strategy for recovering the hemicellulosic fraction from lignocellulosic biomass. Discussions about potential products to be generated, current market profile, and perspectives and challenges of applying the technique are also addressed.

Furfural biotransformation in Acinetobacter baylyi ADP1 and Acinetobacter schindleri ACE.

OBJECTIVES: To determine furfural biotransformation capabilities of Acinetobacter baylyi ADP1 and Acinetobacter schindleri ACE. RESULTS: Acinetobacter baylyi ADP1 and A. schindleri ACE could not use furfural as sole carbon source but when acetate was used as substrate, ADP1 and ACE biotransformed 1 g furfural/l in 5 and 9 h, respectively. In both cases, the product of this biotransformation was difurfuryl-ether as shown by FT-IR and 1H and 13C NMR spectroscopy. The presence of furfural decreased the specific growth rate in acetate by 27% in ADP1 and 53% in ACE. For both strains, the MIC of furfural was 1.25 g/l. Nonetheless, ADP1 biotransformed 2 g furfural/l at a rate of 1 g/l/h in the stationary phase of growth. A transcriptional analysis of possible dehydrogenases involved in this biotransformation, identified that the areB and frmA genes were highly overexpressed after the exposure of ADP1 to furfural. The products of these genes are a benzyl-alcohol dehydrogenase and an alcohol dehydrogenase. CONCLUSIONS: Acinetobacter baylyi ADP1 is a candidate for the biological detoxification of furfural, a fermentation inhibitor present in lignocellulosic hydrolysates, with the possible direct involvement of the AreB and FrmA enzymes in the process.

Thermal properties and volatile compounds profile of commercial dark-chocolates from different genotypes of cocoa beans (Theobroma cacao L.) from Latin America.

There is a growing interest in the identification of chemometric markers that allow the distinction and authentication of dark-chocolates according to their cocoa geographical origin and/or genotype. However, samples derived from Latin American cocoa, including specimens from North and South America, have not been studied in this context. An exploration of the melting behavior, fat composition, bioactive content, and volatile profile of commercial darkchocolates was conducted to identify possible patterns related to the genotype and/or origin of cocoa from Latin America. The melting properties were evaluated by DSC and related to fat content and fatty acids profile. Total polyphenol, anthocyanin, methylxanthine, and catechin content were analyzed. Finally, the volatile compounds were extracted and identified by HS-SPME/GC-MS and were analyzed through Principal Component Analysis (PCA) and the Hierarchical Cluster Analysis Heatmap (HCA Heatmap). The fatty acids profile showed a relationship with the melting properties of dark chocolate. The samples exhibited two glass-transition temperatures (Tg) at ≈19 °C and ≈25.5 °C, possibly related to traces of unstable polymorphic forms of monounsaturated triacylglycerides. The analysis of bioactive compounds demonstrated great variability among samples independent of the cocoa origin, genotype, and content. The PCA and HCA Heatmaps allowed discriminating against the chocolates in relation to the cocoa origin and genotype. Compounds like tetramethylpyrazine, trimethylpyrazine, benzaldehyde, and furfural could be considered as dark-chocolate aroma markers derived from Latin American cocoas (North American region). The 2-phenylethyl alcohol, 2-methylpropanoic acid, 2,3-butanediol, 2-nonanone, and limonene for derived from South America. And the 2-phenylethyl acetate, 3-methyl-butanal, and cinnamaldehyde could allow to distinguishing between regional genotypes.

Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural.

In this work, we investigated the role of solid-state dealumination by (NH4)2SiF6 (25% Al removal and 13% Si insertion), the impregnation of niobium (10, 18, and 25 wt. %) on dealuminated *BEA (DB) zeolite and their catalytic properties in ethanol and xylose transformations. Among all the studied catalysts, 18%Nb-DB showed increased mesoporosity and external areas. A leveling effect in the number and strength of the proposed two sites (Brønsted and Lewis) present in the catalyst (n1 = 0.24 mmol g-1, -ΔH1 = 49 kJ mol-1, and n2 = 0.20 mmol g-1, -ΔH2 = 42 kJ mol-1) in the catalyst 18%Nb-DB, might be responsible for its good activity. This catalyst presented the highest selectivity for diethyl ether, DEE (97%) with 61% conversion after 50 ethanol pulses at 230 °C (turnover number, TON DEE = 1.15). These features allowed catalytically fruitful bonding of the ethanol molecules to the neighboring sites on the channels, facilitating bimolecular ether formation through a possible SN2 mechanism. The same catalyst was active and selective for transformation of xylose at 180 °C, showing 64% conversion and 51% selectivity for furfural (TON Furfural = 24.7) using water as a green solvent.

Analysis of volatile compounds of five varieties of Maya cocoa during fermentation and drying processes by Venn diagram and PCA.

Fermented cocoa beans can be described as a complex matrix that integrates the chemical history of beans, their processing, and environmental factors. This study presents an analysis that aims to identify volatile compounds of five varieties of fine-aroma cocoa types. The cocoa types studied were Carmelo, Rojo Samuel, Lagarto, Arcoiris, Regalo de Dios, that grow in the Maya lands of Chiapas, Mexico. Profile of volatile compounds was obtained from each cacao type during fermentation and drying process. This profile of volatile compounds also was compared with beans unfermented, using a statistical analysis of Venn diagram and a multivariate Analysis of Principal Components (PCA). One hundred nine different compounds were identified by SPME-HS GC-MS, these compounds mainly related to desirable aromatic notes generated by esters, aldehydes, ketones, and alcohols. The differences in chemical composition of the volatile compounds were associated mainly with the process and not to cocoa varieties. Fermented dry cocoa beans showed a higher content of esters, aldehydes, pyrazines, alcohols, some acids, and furans where Lagarto (CL), Rojo Samuel (CR), and Regalo de Dios (TRD) cocoas type showed a more interesting aromatic profile. On the other hand, as expected dry unfermented cocoas presented a few numbers of aroma compounds, in the five cacao types, where alcohols, ketones and hydrocarbons predominated.

Phenolic, oxylipin and fatty acid profiles of the Chilean hazelnut (Gevuina avellana): Antioxidant activity and inhibition of pro-inflammatory and metabolic syndrome-associated enzymes.

Roasted cotyledons of the Chilean hazelnut (Gevuina avellana) are appreciated as snacks. The aim of our work was to assess the fatty acid, oxylipin and phenolic composition using gas chromatography (GC) coupled to mass spectrometry (MS), ultra- high performance liquid chromatography (UHPLC) coupled to MS and HPLC coupled to diode array detector (HPLC-DAD). Additionally, various antioxidant activities were assessed. The inhibition of α-glucosidase, α-amylase, lipase, cyclooxygenases-1 and -2 (COX-1/COX-2), and lipoxygenase was determined. The main fatty acids were oleic and 7-hexadecenoic acids. Eight phytoprostanes and three phytofurans were identified and quantified. Hydroxybenzoic and hydroxycinnamic acids were the main phenolic compounds. Oils showed antioxidant activity determined by EPR, and inhibition of COX-1/COX-2. The statistical analysis showed that the roasting does not affect the composition of the samples. The occurrence of oxylipins in this species is reported for the first time. Chilean hazelnuts can be considered a source of health promoting compounds.

Carbonyl compounds in wine: factors related to presence and toxic effects / Compostos carbonílicos em vinho: fatores relacionados a presença e efeitos tóxicos

The objective of this study was to review technological and toxicological factors related to presence of carbonyl compounds found in wines, including acetaldehyde, formaldehyde, acrolein, ethyl carbamate (EC) and furfural. Acetaldehyde and formaldehyde may be formed through the ethanol and methanol oxidation, respectively. Acrolein may arise as a thermal degradation product of glycerol, amino acids, carbohydrates and triglycerides or by metabolic activity of microorganisms. In addition, acrolein and furfural are formed during wood combustion; therefore, these aldehydes may be present in raw materials due to the environmental contamination. Furfural is also a product of the Maillard reaction formed from sugars and amino acids, while ethyl carbamate occurs through the reaction between urea and ethanol. These compounds may react with SO2 and phenolic compounds to form non-volatile adducts, which positively modulates color stability, astringency and aroma in wine. However, when ingested through wine, electrophilic carbonyl compounds may form adducts with nucleophilic targets, such as DNA, resulting in genotoxicity along the gastrointestinal tract. Furthermore, carbonyl compounds induce the increase of reactive oxygen species and can trigger apoptosis, in addition to hepatocellular adenoma and carcinoma as a consequence of chronic hepatotoxicity. Neurodegenerative diseases may be related to the exposure to carbonyl compounds. Therefore, strategies to reduce the levels of these compounds should be studied in order to get the most out of the beneficial functional properties of wine consumption.(AU)

O objetivo deste estudo foi revisar os fatores tecnológicos e toxicológicos relacionados à presença de compostos carbonílicos encontrados em vinhos, incluindo acetaldeído, formaldeído, acroleína, carbamato de etila (CE) e furfural. O acetaldeído e o formaldeído podem ser formados através da oxidação do etanol e do metanol, respectivamente. A acroleína pode surgir como um produto de degradação térmica de glicerol, aminoácidos, carboidratos e triglicerídeos ou pela atividade metabólica de microorganismos. Além disso, a acroleína e o furfural são formados durante a combustão da madeira. Portanto, esses aldeídos podem estar presentes nas matérias-primas devido à contaminação ambiental. O furfural é também um produto da reação de Maillard formado a partir de açúcares e aminoácidos, enquanto o carbamato de etila ocorre através da reação entre uréia e etanol. Estes compostos podem reagir com SO2 e compostos fenólicos para formar adutos não voláteis, que modulam positivamente a estabilidade da cor, adstringência e aroma no vinho. No entanto, quando ingeridos através do vinho, os compostos carbonílicos que são eletrofílicos podem formar adutos com alvos nucleofílicos, como o DNA, resultando em genotoxicidade ao longo do trato gastrintestinal. Além disso, os compostos carbonílicos também induzem o aumento de espécies reativas de oxigênio e podem desencadear a apoptose, além de adenoma e carcinoma hepatocelular como consequência da hepatotoxicidade crônica. Doenças neurodegenerativas podem estar relacionadas à exposição aos compostos carbonílicos. Com isso, estratégias para reduzir os níveis desses compostos devem ser estudadas para obter o máximo das propriedades funcionais benéficas do consumo de vinho.(AU)

Thermochemistry and kinetic analysis for the conversion of furfural to valuable added products.

Furfural is a valuable oxygenated compound derived from the thermal decomposition of biomass, and is one of the major problems of bio-oil upgrading. Due to its high reactivity, this compound requires further upgrading to more stable products such as furfuryl alcohol, 2-methylfuran (MF), furan, 2-methyltetrahydrofuran, and tetrahydrofuran. The thermochemical data and kinetic analysis of the reactions involved in the conversion of furfural were investigated by molecular modeling to guide experimental investigations in the process of designing efficient catalysts that allows the control of the reaction pathways in specific directions, towards the production of fuel precursors or chemicals. All calculations for reactants, intermediates, and products were performed using the long range corrected functional WB97XD, with the basis set 6-311+g(d,p), under the density functional theory framework. Thermochemistry results suggest that furfural hydrogenation to form furfuryl alcohol is spontaneous up to a temperature of 523 K, but beyond this temperature the reaction becomes a nonspontaneous process. By contrast, the decarbonylation of furfural was thermodynamically favored at temperatures greater than 523 K. Therefore, furan is a thermodynamically favored product, while furfuryl alcohol is kinetically preferred. Once furfuryl alcohol is formed, the hydrogenolysis path to produce methylfuran is favored kinetically and thermodynamically, compared to the ring-hydrogenation towards tetrahydrofurfuryl alcohol. Gas phase thermodynamic properties and rate constants of the reactions involved in the conversion of furfural were calculated and compared against existing experimental data. This study provides the basis for further vapor phase catalytic studies required for upgrading of furans/furfurals to value-added chemicals. Graphical abstract Furan is a thermodynamically favored product, while furfuryl alcohol is kinetically preferred.

Carbonyl compounds in wine: factors related to presence and toxic effects / Compostos carbonílicos em vinho: fatores relacionados a presença e efeitos tóxicos

ABSTRACT: The objective of this study was to review technological and toxicological factors related to presence of carbonyl compounds found in wines, including acetaldehyde, formaldehyde, acrolein, ethyl carbamate (EC) and furfural. Acetaldehyde and formaldehyde may be formed through the ethanol and methanol oxidation, respectively. Acrolein may arise as a thermal degradation product of glycerol, amino acids, carbohydrates and triglycerides or by metabolic activity of microorganisms. In addition, acrolein and furfural are formed during wood combustion; therefore, these aldehydes may be present in raw materials due to the environmental contamination. Furfural is also a product of the Maillard reaction formed from sugars and amino acids, while ethyl carbamate occurs through the reaction between urea and ethanol. These compounds may react with SO2 and phenolic compounds to form non-volatile adducts, which positively modulates color stability, astringency and aroma in wine. However, when ingested through wine, electrophilic carbonyl compounds may form adducts with nucleophilic targets, such as DNA, resulting in genotoxicity along the gastrointestinal tract. Furthermore, carbonyl compounds induce the increase of reactive oxygen species and can trigger apoptosis, in addition to hepatocellular adenoma and carcinoma as a consequence of chronic hepatotoxicity. Neurodegenerative diseases may be related to the exposure to carbonyl compounds. Therefore, strategies to reduce the levels of these compounds should be studied in order to get the most out of the beneficial functional properties of wine consumption.

RESUMO: O objetivo deste estudo foi revisar os fatores tecnológicos e toxicológicos relacionados à presença de compostos carbonílicos encontrados em vinhos, incluindo acetaldeído, formaldeído, acroleína, carbamato de etila (CE) e furfural. O acetaldeído e o formaldeído podem ser formados através da oxidação do etanol e do metanol, respectivamente. A acroleína pode surgir como um produto de degradação térmica de glicerol, aminoácidos, carboidratos e triglicerídeos ou pela atividade metabólica de microorganismos. Além disso, a acroleína e o furfural são formados durante a combustão da madeira. Portanto, esses aldeídos podem estar presentes nas matérias-primas devido à contaminação ambiental. O furfural é também um produto da reação de Maillard formado a partir de açúcares e aminoácidos, enquanto o carbamato de etila ocorre através da reação entre uréia e etanol. Estes compostos podem reagir com SO2 e compostos fenólicos para formar adutos não voláteis, que modulam positivamente a estabilidade da cor, adstringência e aroma no vinho. No entanto, quando ingeridos através do vinho, os compostos carbonílicos que são eletrofílicos podem formar adutos com alvos nucleofílicos, como o DNA, resultando em genotoxicidade ao longo do trato gastrintestinal. Além disso, os compostos carbonílicos também induzem o aumento de espécies reativas de oxigênio e podem desencadear a apoptose, além de adenoma e carcinoma hepatocelular como consequência da hepatotoxicidade crônica. Doenças neurodegenerativas podem estar relacionadas à exposição aos compostos carbonílicos. Com isso, estratégias para reduzir os níveis desses compostos devem ser estudadas para obter o máximo das propriedades funcionais benéficas do consumo de vinho.

Novel Ethanol- and 5-Hydroxymethyl Furfural-Stimulated ß-Glucosidase Retrieved From a Brazilian Secondary Atlantic Forest Soil Metagenome.

Beta-glucosidases are key enzymes involved in lignocellulosic biomass degradation for bioethanol production, which complete the final step during cellulose hydrolysis by converting cellobiose into glucose. Currently, industry requires enzymes with improved catalytic performance or tolerance to process-specific parameters. In this sense, metagenomics has become a powerful tool for accessing and exploring the biochemical biodiversity present in different natural environments. Here, we report the identification of a novel ß-glucosidase from metagenomic DNA isolated from soil samples enriched with decaying plant matter from a Secondary Atlantic Forest region. For this, we employed a functional screening approach using an optimized and synthetic broad host-range vector for library production. The novel ß-glucosidase - named Lfa2 - displays three GH3-family conserved domains and conserved catalytic amino acids D283 and E487. The purified enzyme was most active in pH 5.5 and at 50°C, and showed hydrolytic activity toward several pNP synthetic substrates containing ß-glucose, ß-galactose, ß-xylose, ß-fucose, and α-arabinopyranose, as well as toward cellobiose. Lfa2 showed considerable glucose tolerance, exhibiting an IC50 of 300 mM glucose and 30% of remaining activity in 600 mM glucose. In addition, Lfa2 retained full or slightly enhanced activity in the presence of several metal ions. Further, ß-glucosidase activity was increased by 1.7-fold in the presence of 10% (v/v) ethanol, a concentration that can be reached in conventional fermentation processes. Similarly, Lfa2 showed 1.7-fold enhanced activity at high concentrations of 5-hydroxymethyl furfural, one of the most important cellulase inhibitors in pretreated sugarcane bagasse hydrolysates. Moreover, the synergistic effect of Lfa2 on Bacillus subtilis GH5-CBM3 endoglucanase activity was demonstrated by the increased production of glucose (1.6-fold). Together, these results indicate that ß-glucosidase Lfa2 is a promissory enzyme candidate for utilization in diverse industrial applications, such as cellulosic biomass degradation or flavor enhancement in winemaking and grape processing.

Influence of genetic background of engineered xylose-fermenting industrial Saccharomyces cerevisiae strains for ethanol production from lignocellulosic hydrolysates.

An industrial ethanol-producing Saccharomyces cerevisiae strain with genes of fungal oxido-reductive pathway needed for xylose fermentation integrated into its genome (YRH1415) was used to obtain haploids and diploid isogenic strains. The isogenic strains were more effective in metabolizing xylose than YRH1415 strain and able to co-ferment glucose and xylose in the presence of high concentrations of inhibitors resulting from the hydrolysis of lignocellulosic biomass (switchgrass). The rate of xylose consumption did not appear to be affected by the ploidy of strains or the presence of two copies of the xylose fermentation genes but by heterozygosity of alleles for xylose metabolism in YRH1415. Furthermore, inhibitor tolerance was influenced by the heterozygous genome of the industrial strain, which also showed a marked influenced on tolerance to increasing concentrations of toxic compounds, such as furfural. In this work, selection of haploid derivatives was found to be a useful strategy to develop efficient xylose-fermenting industrial yeast strains.

Influence of ripeness and maceration of the grapes on levels of furan and carbonyl compounds in wine - Simultaneous quantitative determination and assessment of the exposure risk to these compounds.

The validated method based on the use of headspace solid phase microextraction (HS-SPME) coupled with the comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection (GC×GC/TOFMS) proved to be appropriate for this first simultaneous quantitative determination of six toxic compounds (formaldehyde, acetaldehyde, ethyl carbamate, furan, furfural and acrolein) found in wines. Acetaldehyde and acrolein coeluted with other wine compounds, which indicated that difficulties could arise if only one-dimensional gas chromatography was used for the determination of these compounds. The advancement of the ripeness degree and increasing the grape maceration time seems to result in higher concentrations of toxic compounds. The exposure to furan, acrolein and ethyl carbamate through wine consumption may pose risks to consumer health, since calculated MOE values were lower than 10,000.

Physicochemical and sensory (aroma and colour) characterisation of a non-centrifugal cane sugar ("panela") beverage.

Non-centrifugal cane sugar (NCS), also called "panela", is a high carbohydrate-content food obtained by boil evaporation of the sugar cane juice. This study was undertaken to assess physicochemical properties and sensory characteristics of panela beverage at two different concentrations. Evaluation of pH, °Brix, and colour (tristimulus colorimetry) was carried out in all panela drink samples. In order to characterise the odour-active volatiles of the beverage, a simultaneous steam distillation-solvent extraction method was applied using a mixture of diethyl ether-pentane (1:1,w/w) as solvent. The Aroma Extract Dilution Analysis revealed the presence of six odour-active compounds, being 2-methyl pyrazine the key aroma compound of this beverage. PCA (Principal Component Analysis) showed that there were no differences in the aroma and physicochemical properties (pH and °Brix) with respect to the geographical origin of analysed samples; however colour depends on heating during processing of NCS.

Microwave-Assisted Selective Hydrogenation of Furfural to Furfuryl Alcohol Employing a Green and Noble Metal-Free Copper Catalyst.

Green, inexpensive, and robust copper-based heterogeneous catalysts achieve 100 % conversion and 99 % selectivity in the conversion of furfural to furfuryl alcohol when using cyclopentyl-methyl ether as green solvent and microwave reactors at low H2 pressures and mild temperatures. The utilization of pressurized microwave reactors produces a 3-4 fold increase in conversion and an unexpected enhancement in selectivity as compared to the reaction carried out at the same conditions using conventional autoclave reactors. The enhancement in catalytic rate produced by microwave irradiation is temperature dependent. This work highlights that using microwave irradiation in the catalytic hydrogenation of biomass-derived compounds is a very strong tool for biomass upgrade that offers immense potential in a large number of transformations where it could be a determining factor for commercial exploitation.

Xylitol production and furfural consumption by a wild type Geotrichum sp

Background: Xylitol is a five carbons polyol with promising medical applications. It can be obtained from chemical D-xylose reduction or by microbial fermentation of Sugarcane Bagasse Hemicellulosic Hydrolysate. For this last process, some microbial inhibitors, as furfural, constitute severe bottleneck. In this case, the use of strains able to produce xylitol simultaneously to furfural neutralization is an interesting alternative. A wild-type strain of Geotrichum sp. was detected with this ability, and its performance in xylitol production and furfural consumption was evaluated. Furthermore, were analyzed its degradation products. Results: Geotrichum sp. produced xylitol from D-xylose fermentation with a yield of 0.44 g-g-1. Furfural was fully consumed in fermentation assay and when provided in the medium until concentration of 6 g-L-1. The furfural degradation product is not an identified molecule, presenting a molecular weight of 161 g-mol-1, an uncommon feature for the microbial metabolism of this product. Conclusion: This strain presents most remarkable potential in performing furfural consumption simultaneous to xylitol production. Subsequent efforts must be employed to establish bioprocess to simultaneous detoxification and xylitol production by Geotrichum sp.

Evaluation of antioxidant capacity in coffees marketed in Colombia: Relationship with the extent of non-enzymatic browning.

Fifty-eight samples of commercial Colombian coffee with different characteristics (soluble, ground, decaffeinated, etc) were evaluated for antioxidant capacity (AC) (ABTS and FRAP), total soluble phenolics (TP), browning index (BI), color parameters (L(∗), a(∗), b(∗), c(∗) and h(∗)), HMF and furfural. The AC in Colombian coffees was very varied (164-1000, 100.8-885.9µmol of Trolox equiv/g and 12.5-127mg gallic acid equiv/g, respectively for ABTS, FRAP and TP). AC, TP, BI, color, HMF and furfural values were higher (p<0.05) in soluble coffees than in ground ones, showing the lyophilized samples which showed the highest average values. Significant lineal correlations (p<0.05) were found between AC and color parameters, BI, HMF. No significant (p<0.05) differences in the AC between the different types of coffee were found. This work confirms the direct relationship between the rate of non-enzymatic browning and antioxidant capacity.

In house validation from direct determination of 5-hydroxymethyl-2-furfural (HMF) in Brazilian corn and cane syrups samples by HPLC-UV.

In this work the development and in house validation of the HMF direct determination in corn and cane syrups by HPLC-UV was carried out for the first time. The separation was done with isocratic elution of a mobile phase comprising water (with 0.5% formic acid) and acetonitrile (90:10, v/v) on Phenomenex C18 column (5.0 µm, 4.6 × 150 mm), at 30 °C, flow rate of 0.8 mL min(-1) and detection at 285 nm. The validated method showed excellent performance with low limits (LOD and LOQ of 0.09 and 0.26 mg L(-1), respectively), good accuracy (recovery rates between 100% and 104%) and precision (RSD's for repeatability and intermediate precision between 0.57% and 6.43%). Good selectivity and linearity were also observed. HMF contents in both foods were very high (406.6-2121.3 mg kg(-1) for corn syrup and 109.2-893.1 mg kg(-1) for cane syrup), which arouses concern about food safety of these products.