Concentrations Of 5-hydroxymethylfurfural Research Articles

Model-Assisted Optimization of Xylose, Arabinose, Glucose, Mannose, Galactose and Real Hemicellulose Streams Dehydration To (Hydroxymethyl)Furfural and Levulinic Acid.

Conversion of hemicellulose streams and the constituent monosaccharides, xylose, arabinose, glucose, mannose, and galactose, was conducted to produce value-added chemicals, including furfural, hydroxymethylfurfural (HMF), levulinic acid and anhydrosugars. The study aimed at developing a kinetic model relevant for direct post-Organosolv hemicellulose conversion. Monosaccharides served as a tool to in detail describe the kinetic behavior and segregate contribution of hydrothermal decomposition and acid catalyzed dehydration at the temperature range of 120-190 °C. Catalyst free aqueous media demonstrated enhanced formation of furanics, while elevated temperatures led to significant saccharide isomerization. The introduction of sulfuric and formic acids maximized furfural yield and significantly reduced HMF concentration by facilitating its rehydration into levulinic acid (46 mol%). Formic acid additionally substantially enhanced formation of anhydrosaccharides. An excellent correlation between modeled and experimental data enabled process optimization to maximize furanic yield in two distinct hemicellulose streams. Sulfuric acid-containing hemicellulose stream achieved the highest furfural yield after 30 minutes at 238 °C, primarily due to the high Ea for pentose dehydration (150 - 160 kJmol-1). Contrarily, formic acid-containing hemicellulose stream enabled maximal furfural yield at more moderate temperature and extended reaction time due to its lower Ea for the same reaction step (115 - 125 kJmol-1).

Investigation of formation of AGEs precursors, hydroxymethylfurfural and malondialdehyde in oleogel added cakes using an in vitro simulated gastrointestinal digestive system

The baking process has the potential to generate health-risk compounds, including products from lipid oxidation and Maillard reaction. Pre- and post-digestion levels of hydroxymethylfurfural (HMF), malondialdehyde (MDA), glyoxal (GO), and methylglyoxal (MGO) were studied in cakes formulated with hazelnut and sunflower oil, along with their oleogels as margarine substitutes. The concentration of HMF in oil and oleogel-formulated cakes increased after digestion compared to cakes formulated with margarine. The MDA values were between 82 and 120 μg/100 g in oil and oleogel formulated cakes before digestion and a decrease was observed after digestion. The substitution of margarine with oil and oleogels resulted in the production of high amounts of GO and MGO in cakes. However, the highest bioaccessibility as 318.2% was found in cakes formulated by margarine for GO. Oleogels may not pose a potential health benefit compared to margarines due to the formation of HMF, MDA, GO, and MGO.

Physicochemical, microbiological, and sensory properties of stingless bee honey from Argentina

The physicochemical parameters, antioxidant activity, and sensory properties were determined in stingless bee honeys from two bee species and different phytogeographic regions of the Chaco province (Argentina). All honeys showed similar moisture content, colour, and hydroxymethyl furfural concentration. The samples from the oriental estuaries showed the lowest free acidity, ash content, and electrical conductivity. The honey produced by Tetragonisca fiebrigi (Schwarz) had a higher ash content than honeys produced by Scaptotrigona jujuyensis (Schrottky). However, the electrical conductivity of honeys produced by both bee species was similar. The HPLC sugar analysis, total polyphenol and flavonoid content, and antioxidant activity (ABTS) showed no significant differences between the different geographic zones or bee species. The wood aroma and sweet taste were chosen as the best sensory descriptors of the honeys. The results of the multivariate techniques used showed that is not possible to classify honeys according to its geographical origin or bee species. Most of the honey samples meet the required microbiological standards and could be considered safe for consumption.

Changes in quality and bacterial profiles of Tualang and Kelulut honeys preserved by post‐harvest maturation

SummaryPost‐harvest maturation of two Malaysian honeys, the Tualang and Kelulut was studied by measuring changes in physicochemical and antioxidant properties, hydroxymethylfurfural (HMF) contents and bacterial profiles at room temperature of 23–26 °C. After maturation at the recommended period of 26 weeks, water activity of both honeys increased between 0.89% and 2.34% while free acidity increased between 2.05% and 2.24%. Results suggested the prominence of fermentation reactions in honey during post‐harvest maturation as fructose concentration reduced by 10.6% and 1.05% for the Tualang and Kelulut honey, respectively, while HMF concentrations were kept at a safe limit of 48.00 and 61.23 mg/kg honey. The total phenolic content of Tualang and Kelulut honey increased significantly by 12.61% and 54.66% respectively. The highlight of this post‐harvest maturation process for Kelulut honey was the improvement found in antioxidant properties of DPPH radical scavenging activity by 10.01%–54.74% and also the probiotic‐like potential in terms significant increase in relative abundance of the Bacillus genera to 2.6% and Lactobacillus to 6.25% at 26 weeks. The prolonged maturation process up to 1 year however revealed continuous accumulation of HMF to values above 80 mg/kg honey, surpassing the limits by the Codex Alimentarius Commission despite improvements of antioxidant properties and bacterial profiles.

Influence of heavy metal ions and storage time on hydroxymethylfurfural formation in honey collected from Ilu Woreda, Oromia Regional State, Ethiopia

The effect of heavy metals on the formation of hydroxymethyl furfural (HMF) from degradation of reducing sugars in honey collected from Ilu Woreda, West Shewa Zone of Oromia Regional State, Ethiopia were studied. The concentration level of Pb, Cd, Cr and Ni in honey sample was determined using AOAC Official Method. The concentration of HMF in honey was determined using international honey commission standards. The concentrations of heavy metals in fresh honey were 11 ± 0.001, 454 ± 0.002, 630 ± 0.001 and 1 ± 0.001 µg kg-1 for Pb, Cr, Ni and Cd, respectively. The influence of heavy metals on the formation of HMF in honey samples was studied on 5, 30 and 60 days after spiking at concentration level of 10,000 µg kg-1 of each heavy metal. The concentration of HMF for untreated honey samples was ranged 1380-2200 µg kg-1 for the storage time of 5, 30 and 60 days. The concentration of HMF in honey samples spiked with Pb, Ni, Cr and Cd were found to be in the range of 2100-2150, 1900-2430, 2100-2270 and 2050-2330 µg kg-1, respectively. The results of this study indicate that contamination of honey with heavy metal facilitate the formation of HMF.
 KEY WORDS: Fresh honey, HMF, Heavy metal ions, HPLC-DAD and Honey quality
 Bull. Chem. Soc. Ethiop. 2024, 38(1), 1-10. DOI: https://dx.doi.org/10.4314/bcse.v38i1.1

Determination of Possible Adulteration and Quality Assessment in Commercial Honey.

This study aims to predict several quality traits in commercial honey samples simultaneously and to reveal possible honey adulteration using a field-deployable portable infrared spectrometer without any sample preparation. A total of one hundred and forty-seven commercial honey samples were purchased from local and online markets in Turkey and the United States of America (USA), and their soluble solids (°Brix), pH, free acidity, moisture, water activity (aw), glucose, fructose, sucrose, and hydroxymethyl furfural (HMF) contents were determined using reference methods. The HMF (n = 11 samples) and sucrose (n = 21) concentrations were higher than the regulatory limits in some tested samples. The exceeding HMF content may imply temperature abuse during storage and prolonged storing. On the other hand, high sucrose content may indicate possible adulteration with commercial sweeteners. Therefore, soft independent modeling of class analogies (SIMCA) analysis was conducted to reveal this potential sweetener adulteration in the samples, and the SIMCA model was able to identify all the flagged samples. The suggested FT-IR technique may be helpful in regulatory bodies in determining honey authenticity issues as well as assessing the quality characteristics of honey samples in a shorter period and at a lower cost.

Carboxymethyl-Cellulose-Containing Ag Nanoparticles as an Electrochemical Working Electrode for Fast Hydroxymethyl-Furfural Sensing in Date Molasses

Novel biosensors based on carboxymethyl cellulose extract from date palm fronds containing Ag nanoparticles as an electrochemical working electrode for fast hydroxymethylfurfural (HMF) sensing in date molasses were prepared. The morphological, structural, and crystallinity characteristics of the prepared Ag@CMC were described via SEM, DLS, TEM, and XRD. In addition, Raman spectroscopy and UV-VIS spectroscopy were performed, and thermal stability was studied. The investigated techniques indicated the successful incorporation of AgNPs into the CMC polymer. The sensing behavior of the prepared AgNPs@CMC electrode was studied in terms of cyclic voltammetry and linear scan voltammetry at different HMF concentrations. The results indicated high performance of the designed AgNPs@CMC, which was confirmed by the linear behavior of the relationship between the cathodic current and HMF content. Besides, real commercial samples were investigated using the novel AgNPs@CMC electrode.

Biochar and wood ash amended anaerobic digestion of hydrothermally pretreated lignocellulosic biomass for biorefinery applications

This study investigated the effect of biochar and wood ash amendment on the anaerobic digestion of hydrothermally pretreated lignocellulosic biomass. Hydrothermal pretreatment was performed on switchgrass at 200, 250, and 300 °C with 0, 30, and 60 min of retention times. The pretreatment method was optimized using the response surface method for enhanced methane production. At the optimum pretreatment (200 °C/0 min retention time), a specific methane yield of 256.9 mL CH4/g volatile solids (VS), corresponding to an increase of 32.8% with respect to the untreated substrate, was obtained. Hydrothermal pretreatment was beneficial for methane production at temperatures lower than 220 °C and retention times shorter than 20 min. At more severe pretreatment conditions than 220°-20 min, sugars were degraded into other products, causing a decrease in the methane yield. The hydrothermal degradation products, i.e., acetic acid, lactic acid, furfural, and hydroxymethylfurfural concentrations, were also measured and modeled. The addition of biochar and wood ash to BMP assays were tested at 2, 9, 16 g/g VSinoculum ratios and <63, 63–125, 125–250 μm particle sizes. A decline in methane production was observed for all tested doses and particle sizes of both additives. The decline in the methane potential was proportional to the doses and particle sizes. Kinetic modeling of BMP test results also supported that using the additives was not beneficial. Based on the result of this study, it was found that the use of biochar and wood ash in a pretreated lignocellulosic biomass processing biorefinery would not be beneficial.

Glyoxal induced glycative insult suffered by immunoglobulin G and fibrinogen proteins: A comparative physicochemical characterization to reveal structural perturbations.

Glycation of proteins results in structural alteration, functional deprivation, and generation of advanced glycation end products (AGEs). Reactive oxygen species (ROS) that are generated during in vivo autoxidation of glucose induces glycoxidation of intermediate glycation-adducts, which in turn give rise to aldehyde and/or ketone groups containing dicarbonyls or reactive carbonyl species (RCS). RCS further reacts non-enzymatically and starts the glycation-oxidation vicious cycle, thus exacerbating oxidative, carbonyl, and glycative stress in the physiological system. Glyoxal (GO), a reactive dicarbonyl that generates during glycoxidation and lipid peroxidation, contributes to glycation. This in vitro physicochemical characterization study focuses on GO-induced glycoxidative damage suffered by immunoglobulin G (IgG) and fibrinogen proteins. The structural alterations were analyzed by UV-vis, fluorescence, circular dichroism, and Fourier transform infrared (FT-IR) spectroscopy. Ketoamines, protein carbonyls, hydroxymethylfurfural (HMF), free lysine, free arginine, carboxymethyllysine (CML), and protein aggregation were also quantified. Structural perturbations, increased concentration of ketoamines, protein carbonyls, HMF, and malondialdehyde (MDA) were reported in glycated proteins. The experiment results also validate increased oxidative stress and AGEs formation i.e. IgG-AGEs and Fib-AGEs. Thus, we can conclude that AGEs formation during GO-mediated glycation of IgG and fibrinogen could hamper normal physiology and might play a significant role in the pathogenesis of diabetes-associated secondary complications.

Evaluation of the risks for animal health related to the presence of hydroxymethylfurfural (HMF) in feed for honey bees.

The European Commission has asked the EFSA to evaluate the risk for animal health related to the presence of hydroxymethylfurfural (HMF) in honey bee feed. HMF is a degradation product of particular sugars and can be present in bee feed. HMF is of low acute toxicity in bees but causes increased mortality upon chronic exposure. A benchmark dose lower limit 10% (BMDL10) of 1.16 μg HMF per bee per day has been calculated from mortalities observed in a 20‐day study and established as a Reference Point covering also mortality in larvae, drones and queens for which no or insufficient toxicity data were available. Winter bees have a much longer lifespan than summer bees and HMF shows clear time reinforced toxicity (TRT) characteristics. Therefore, additional Reference Point intervals of 0.21–3.1, 0.091–1.1 and 0.019–0.35 µg HMF/bee per day were calculated based on extrapolation to exposure durations of 50, 90 and 180 days, respectively. A total of 219 analytical data of HMF concentrations in bee feed from EU Member States and 88 from Industry were available. Exposure estimates of worker bees and larvae ranged between 0.1 and 0.48, and between 0.1 and 0.51 μg HMF/per day, respectively. They were well below the BMDL10 of 1.16 μg HMF/bee per day, and thus, no concern was identified. However, when accounting for TRT, the probability that exposures were below established reference point intervals was assessed to be extremely unlikely to almost certain depending on exposure duration. A concern for bee health was identified when bees are exposed to HMF contaminated bee feed for several months.

A Rapid HPLC Method for the Simultaneous Determination of Organic Acids and Furans: Food Applications

Concerns over the potential adulteration of commercially produced foods give rise to a requirement for a simple and fast analytical method capable of quantifying potential adulterants. This work demonstrates a simple HPLC method tailored to detect major organic acids and furans within ingredients in commercial food products, for example, pomegranate molasses, balsamic vinegar, and apple cider vinegar. The relative importance of this method is in its simplicity and its use of an environmentally friendly aqueous mobile phase under isocratic conditions, providing results in a less than 20 min runtime. The chromatographic separation was achieved using an Acclaim® OA, 5 µm, 120 Å (4.0 × 250 mm) column; a UV-DAD detector set at 210 nm; and a 200 mM Na2SO4 mobile phase with 0.55 mL/L methanosulfonic acid as a pH modifier. The method was then validated by quantifying the concentration of acetic acid, formic acid, citric acid, and hydroxymethyl furfural (HMF) in pomegranate molasses, balsamic vinegar, and apple cider vinegar commercial products. The concentration of acetic acid and HMF in balsamic vinegar was 80.380 mg/mL (±1.272 mg/mL) and 2.153 mg/mL (±0.021 mg/mL), respectively. The apple cider vinegar was composed only of acetic acid with a concentration of 44.139 mg/mL (±0.053 mg/mL). The concentrations of citric acid and HMF were 123.425 mg/mL (±2.502 mg/mL) and 11.382 mg/mL (±0.582 mg/mL), respectively, in pomegranate molasses. Furthermore, this method is also capable of determining various organic acids and furans in biomass: levulinic acid, formic acid, furfurals, diformylfuran, and gamma-valerolactone.

A model-based experimental design approach to assess the identifiability of kinetic models of hydroxymethylfurfural hydrogenation in batch reaction systems

Hydroxymethylfurfural (HMF) is an organic compound that occurs naturally in many foods and is used as feedstock in numerous chemical processes. HMF can be hydrogenated to form 2,5-Dimethylfuran (DMF), which is an important component in biofuel production. To date, several kinetic models have been proposed and studied in literature for this hydrogenation reaction, including power law models based on reaction species and Langmuir-Hinshelwood-Hougen-Watson (LHHW) models. For these models a critical aspect that has not been addressed in literature is related to their practical identifiability, i.e. the estimability of kinetic parameters from experimental data. Also, none of the existing models propose a temperature dependence of the kinetic parameters.A three-step approach is presented in this paper, which exploits model-based design of experiments (MBDoE) techniques to assess the identifiability of candidate kinetic models of HMF hydrogenation in a batch reaction system. The objective is twofold: (1) to propose new kinetic models of HMF hydrogenation where the temperature is explicitly introduced as an experimental design variable and test the practical estimability of kinetic parameters from concentration data only; (2) to identify the most informative regions of the experimental design space, defined by temperature, experiment duration and initial HMF and DMF concentrations, for achieving a precise estimation of model parameters. Together with a-posteriori statistics obtained from parameter estimation from in-silico data, an MBDoE analysis gives a clear representation of the most informative experimental conditions to be explored in the future experimentation underlining distinct areas of practical parametric identifiability.

Uncovering Insights to the Reaction Mechanism of the Electrochemical Hydrogenation and Hydrogenolysis of Furanic Species

Biomass derived compounds may be used as platform molecules for valorization to value-added products and biofuels. Two such molecules are furfural (FF) and 5-(hydroxymethyl)furfural (HMF). Using electricity as the energy source, FF and HMF can be upgraded by electrochemical hydrogenation and hydrogenolysis (ECH) reactions. The products of interest when FF is used as the starting molecule are the hydrogenation product, furfuryl alcohol (FA), a chemical intermediate, and the hydrogenolysis product, 2-methylfuran (MF), a biofuel. Similarly, HMF undergoes ECH to form 2,5-dihydroxymethylfuran (DHMF), a chemical intermediate, and 2,5-dimethylfuran (DMF), a biofuel. Existing studies probe the effect of electrode, electrolyte, applied potential, and temperature on reaction efficiency and selectivity, however fundamental questions remain about the reaction pathway and kinetics. This study elucidates the reaction pathway of FF and HMF to products through bulk electrolysis ECH.The ECH reactions were carried out via potentiostatic bulk electrolysis in an H-type cell with Cu flag working electrode in acidic electrolyte (0.5M H2SO4). By sampling the electrolyte at various times throughout the reaction, the product distribution with time for the ECH reactions was developed. The concentration of HMF and its products was determined by HPLC and the concentration of FF and its products was determined by GCMS. For 90 minutes of FF ECH, the concentration of both FA and MF increased steadily with reaction time; neither showed signs of further consumption. This observation indicates that FF ECH occurs over two separate, parallel paths to FA and MF. This is further evidenced by the lack of reaction to MF when FA is used as the starting molecule for ECH.

Opuntia ficus indica waste as a cost effective carbon source for lactic acid production by Lactobacillus plantarum

Opuntia ficus indica (OFI) waste was evaluated as a fermentation feedstock for lactic acid production using Lactobacillus plantarum.Dilute acid pretreatment of the OFI cladodes (OFIC) was performed for extracting maximum fermentable sugars by optimizing process parameters using statistical optimization method. The best results were obtained with HCl 1% (v/v), temperature 120 °C, residence time 40 min, granulation 350 µm and substrate loading 5% (w/v), the sugar concentration reached 24 g/L with low concentration of hydroxymethylfurfural. The feasibility of producing lactic acid from OFI fruit peel (OFIFP) as a source of carbon was also investigated. Lactobacillus plantarum was shown to have a capacity for lactic acid production from OFIC350 (granulation 350 µm) hydrolysate and OFIFP extract without detoxification. The highest lactic acid yields of 0.46 and 0.78 g/g were obtained from enzymatic hydrolysate of pretreated OFIC350 and OFIFP extract, respectively.

Tolerance of Ziziphus and Acacia honeys to one year storage conditions and altitude

Objectives: This article investigated the effect of plant origin, storage and altitude on the triglycerides, cholesterol and some physicochemical properties of honey samples. Methods: Nineteen honey samples (9 Ziziphus and 10 Acacia) were involved in this study representing two floral origins and seasons and four altitudes. The plant origin of the honey samples was confirmed microscopically and their quality parameters were analyzed according to the International Honey Commission harmonized methods of honey analysis. The lipid parameters were analyzed using spectrophotometric- enzymatic methods. The SPSS version 20 was used for the statistical analysis of the obtained data. Results: The plant origin significantly affected the honey pH (P = 0.017), moisture (P = 0.009), fructose (P < 0.001) and the total of fructose and glucose (P = 0.001). Honey storage for one year significantly affected the Ziziphus honey pH (P = 0.005), moisture (P = 0.021), conductivity (P = 0.017), fructose (P = 0.036), glucose (P = 0.006) and the total of glucose and fructose (P = 0.013) while all the quality parameters of the stored Acacia honey were insignificantly different than those of the freshly harvested Acacia honey. The hydroxymethylfurfural (HMF) of the freshly harvested honey (Ziziphus of Acacia) was higher than that of the stored honey. The altitude had significant effect on the pH, acidity, moisture, conductivity, fructose, glucose, the total of fructose and glucose and the HMF of the Ziziphus honey while the altitude of the Acacia honey significantly affected the percentages of moisture and fructose only. Conclusions: Acacia honey was tolerant to one year storage at room temperature and to the high altitude climate conditions. Freshly harvested honey samples were with high HMF concentration compared to the stored honey samples.

Identification of bitter‐taste compounds in class‐III caramel colours

AbstractCaramel colours become one of the most widely used colorings in various foods and beverages due to their total miscibility with water and great coloring properties by containing colloidal aggregates. Bitterness in caramel colours can negatively influence their acceptability. The sequential solvent extraction (SSE) and semi‐preparative liquid chromatography (SP‐LC) combined with the taste dilution analysis were applied to identify the most intense bitter‐tasting compounds in class‐III caramel colours. Four main compounds with the highest bitterness intensity were isolated and structurally elucidated based on high resolution‐electrospray ionization‐mass spectrum (HR‐ESI‐MS), nuclear magnetic resonance (NMR) spectroscopy and gas chromatography‐mass spectrum (GC‐MS): 2,3‐dihydro‐3,5‐dihydroxy‐6‐methyl‐4(H)‐pyran‐4‐one (DDMP), 5‐(hydroxymethyl) furfural (HMF), furfural and 5‐methylfurfural (MF). The threshold concentrations of DDMP, HMF, furfural and MF were 14.3, 30.0, 4.4 and 17.5μmol L−1, respectively. Furthermore, two volatile bitter compounds were identified: [5‐(di‐methoxymethyl) furan‐2‐yl] methanol (DMFM) and 2,3,4,4‐tetramethyl‐pentane‐1,3‐diol (TMP). Based on the composition of the caramel colours and the structures of these compounds, Maillard reaction was supported to generate these bitter compounds in caramel colour‐III.

Evaluation of qualitative changes of apple-beetroot juice during long-term storage at different temperatures

The effect of storage conditions on changes of pH, total soluble solids (°Brix), colour, betalains (betacyanins and betaxanthins), and 5-hydroxymethylfurfural was investigated in apple-beetroot juices stored at 2, 7 and 20 °C for 120 days. The results obtained showed that the quality of apple-beetroot juice is significantly influenced by temperature and storage duration. Increasing storage time and temperature induced an apparent rise (P < 0.05) of lightness (L*), yellowness (b*), hue angle, total colour difference (ΔE) and 5-hydroxymethylfurfural. Maximal concentration of 5-hydroxymethylfurfural reached 14.97 ± 0.03 mg/L at 20 °C; however, this concentration is under the allowable maximal level in apple juice (20 mg/L). The increase in total colour difference and 5-hydroxymethylfurfural concentration was associated with a decrease of betacyanins and betaxanthins, confirmed by strong inverse correlations (r from − 0.7991 to − 0.9813). Degradation of both betacyanins and betaxanthins followed the first-order kinetic model and showed positive correlation with redness (a*) and chroma. Higher rate constants (k) for betacyanin degradation (k ≈ 0.0064–0.0285 day−1) in comparison with the rate constants for betaxanthin degradation (k ≈ 0.0073–0.0471 day−1) demonstrate that betacyanins degraded slightly faster. The changes in all monitored characteristics were significantly greater at 20 °C (P < 0.05) than at 7 and 2 °C, except pH and °Brix. Therefore, apple-beetroot juices should be stored at lower temperatures to maintain their acceptable quality.

A model system based on glucose-arginine to monitor the properties of Maillard reaction products.

An arginine-glucose mixture (1:2mol ratio) with pH 9 was heated at 53-100°C for 10-350min, and the effects of process parameters were determined during the Maillard reaction (MR). The heating temperature and time were selected as process conditions and were studied with central composite design. The model system was tested based on the values obtained from antioxidant capacity, browning intensity, pH, acrylamide (AC), and hydroxymethylfurfural (HMF) concentrations. Higher temperatures and longer time resulted in higher antioxidant capacity and browning intensity while lowering the pH values. HMF concentration of MR products was found higher in lower temperatures with longer processing time, whereas AC concentration was found higher in high temperatures.

Bioconversion of 5-Hydroxymethylfurfural (HMF) to 2,5-Furandicarboxylic Acid (FDCA) by a Native Obligate Aerobic Bacterium, Acinetobacter calcoaceticus NL14.

2,5-Furandicarboxylic acid (FDCA), one of the top biomass-based platform chemical, is highly promising for resins and polymers, and it can be prepared from the bio-oxidation of hydroxymethyl furfural (HMF), which can be obtained mainly from lignocellulosic glucose that has a high production potential from not edible biomass.A native strain, Acinetobacter calcoaceticus NL14, that could convert HMF into FDCA is used for combining degradation and fermentation by consolidated bioprocessing (CBP). In this study, it was observed that the initial HMF concentration and pH neutralizer played important roles in the bioconversion of HMF, 5g/L of HMF could be converted by 100% within 48h with 0.5g/L sodium carbonate (Na2CO3) with the production of 0.31g/L FDCA. Extra glucose and hydrogen peroxide (H2O2) addition could further promote the production of FDCA to 0.54g/L with 100% HMF conversion and a higher conversion rate. This report could provide a potential native bacterium for furan chemicals bioconversion and bioelimination, especially for FDCA bioproduction.

Afectación térmica de la miel de abeja en una metodología alternativa, monitoreando hidroximetilfurfural, número de diastasa y vitamina C

La investigación tuvo como objetivo realizar un estudio de afectación térmica de la miel de abeja mediante una metodología alternativa, monitoreando la degradación de vitamina C, hidroximetilfurfural (HMF) y número de diastasa (ND). El estudio se realizó con miel genuina de un apicultor de ASOPROACH (Asociación de Producción Apícola de Chimborazo). Se diseñó una metodología experimental de tratamiento térmico para 300 mL de miel a cuatro temperaturas y tres tiempos cada una: 30, 60, 80 y 90 °C a 15, 30 y 60 minutos. Luego de cada tratamiento térmico se analizó la concentración de HMF, ND, Vit C. (Ruiz, Danesa 2018). Los resultados del análisis mostraron que el mejor tratamiento corresponde a una temperatura de 30 °C por 15 minutos. Para el análisis de la concentración de vitamina C se usó cromatografía líquida de alta resolución (HPLC), se repitió el mejor tratamiento térmico por seis veces, observándose que la vitamina C y todos los parámetros físico-químicos establecidos en la norma NTE INEN 1572 se mantenían en una concentración estable. Los resultados experimentales fueron corroborados con un análisis de varianza (SPSS v21). Se socializó a los apicultores de ASOPROACH la parte experimental de los tratamientos térmicos y sobre la propuesta alternativa artesanal. (Ruiz, Danesa 2018). El incremento de la temperatura y el tiempo de duración afecta los parámetros. La metodología diseñada con un cumplimiento estricto puede ser utilizada discrecionalmente en casos especiales.