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Solar energy‐driven biomass refinery to produce high value‐added chemicals is attracting more and more attention. However, precisely modulating for selective oxidation of biomass‐derived platform chemical is still challenging. Further mechanism study on this oxidation process is highly desirable. In this work, theoretical study on the oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) at the atomic and molecular level is completed by density functional theory, oxidative reaction mechanism is further revealed. The two oxidation reaction pathways were identified, one is the hydroxymethyl group of HMF is oxidized to obtain 2,5‐diformylfuran (DFF) and continue oxidized to form 5‐formyl‐2‐furancarboxylic acid (FFCA) and finally FFCA is oxidized to obtain FDCA, the other is the aldehyde group of HMF is oxidized to form 5‐hydroxymethyl‐2‐furancarboxylic acid (HMFCA), and then oxidized to form FFCA and FDCA. The potential energy surface information of the 24 possible reaction channels at the B3LYP/6‐311 + G(d,p) level was obtained, including geometry structure optimization and frequency calculation of the stationary point. Results showed that hydroxymethyl group is easier to be oxidized to form DFF with the lower reaction energy barrier, this is consisted with most of the experimental results. Compared with O2, the H‐abstract reaction initiated by peroxy radicals of aldehyde or hydroxymethyl group is kinetically favorable. The new findings of two oxidation reaction processes of HMF (alcohol oxidation and aldehyde oxidation) in detail are of great significance for further utilizing and development of HMF. [ABSTRACT FROM AUTHOR]

Brewer's spent grain (BSG) is the most abundant residual in the brewing process. Non-starch polysaccharides such as 1,3-1,4-β-D-glucan (β-glucan) and arabinoxylan (AX) with proven beneficial effects on human health remain in this by-product in high amounts. Incorporating the valuable dietary fiber into the food industry could contribute to a healthy diet. However, a major challenge is extracting these dietary fibers (i.e., β-glucan and AX) from the solid residue. In this study, hydrothermal treatment (HT) was applied to dissolve the remaining water-insoluble carbohydrates from BSG with the aim to extract high amounts of β-glucan and AX. Particular focus was placed on the molecular weight (MW) range above 50 kDa and 20 kDa, respectively, as these are considered to have health-promoting effects. Different treatment temperatures, reaction times, and internal reactor pressures were tested to determine the best process settings to achieve high yields of β-glucan and AX and to examine the influence on their molecular weight distribution (MWD). Overall, 85.1% β-glucan and 77.3% AX were extracted corresponding to 6.3 g per kg BSG at 160 °C and 178.3 g kg−1 at 170 °C, respectively. However, less than 20% of both fiber substances were in the desirable MW range above 50 kDa and 20 kDa, respectively. When lower temperatures of 140 and 150 °C were applied, yields of only 3.0 g kg−1 β-glucan and 128.8 g kg−1 AX were obtained, whereby the proportion of desirable fiber fractions increased up to 45%. Further investigations focused on the heat-induced degradation of monosaccharides and the formation of undesirable by-products (i.e., HMF and furfural) that might pose a health risk. [ABSTRACT FROM AUTHOR]

Copyright of Zywnosc is the property of Polish Society of Food Technologists - Scientific Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nanostructured first row transition metal (Mn, Fe, Co, Ni, and Cu) oxides (TMOs) have shown promise as catalysts for creation of new and ransformative technologies for manufacturing value-added chemicals that are energy- and atom-efficient. Most of the synthesis routes to TMOs involve harsh reaction conditions or prolonged preparation times. Herein, we use potassium superoxide (KO2), a commercially available stable salt of superoxide, as a viable oxidant for rapid but mild redox synthesis of birnessite type layered manganese dioxide (δ-MnO2) nanomaterials. These δ-MnO2 materials are synthesized in a fast (as fast as 5 min), ambient (room temperature), and convenient condition, employing a simple laboratory apparatus (grinding with mortar and pestle followed by washing with water). Characterization studies reveal a hierarchical porosity and sponge-like morphology for the δ-MnO2 nanomaterial, whereas the surface area of the material is tunable as a function of the adopted synthetic aspects. The δ-MnO2 materials deliver promising catalytic activity in the selective aerobic oxidation of 5-hydroxymethylfurfural alcohol (HMF) to 3,5-diformylfuran (DFF), an important probe reaction to transform biomass-derived feedstocks to useful chemicals. Density functional theory (DFT) is used to investigate the interaction of HMF with the catalyst surface and to chart out the energetics pathway of system relaxation, together showcasing various bond dissociations, intermediate steps, and rate limiting kinetics. [ABSTRACT FROM AUTHOR]

Copyright of Food Science & Engineering Research is the property of Ataturk University Coordinatorship of Scientific Journals and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study aimes to investigate the physicochemical properties of seven honey samples to assess their quality as per GCC Standardization Organization (GSO) and international standard parameters. Seven honey samples, four marketed honey samples, and three locally produced Omani honey were collected and analysed for the pH, acidic content, % of insoluble matter, moisture content, proline, hydroxyl methyl furfural (HMF) and total reducing sugar contents. The results showed that pH of the tested honey samples are within the limit however acidity of the three samples did not comply with the prescribed limits. The moisture, proline, and hydroxy methyl furfural (HMF) contents of the honey samples tested are found to be within the acceptable range. However, the % of insoluble matter expressed for locally produced Sidr, Sumer, and Zah'r honey samples was below the maximum limit (0.5%) while marketed honey samples exceeded the limits of GSO (0.1%). The total reducing sugar concentration was below the limit in terms of four samples. Most of the tested honey samples meet the International/GSO standards for quality while a few failed to comply with acidity limits, the total reducing sugars content, and % of insoluble matter. [ABSTRACT FROM AUTHOR]

Honey is a natural food substance considered among functional foods due to its positive effect on human health. Quality of honey is significantly influenced by environmental conditions and botanical origin. This study aimed to determine the element content in honey from Kars, Turkey, as well as the bioactive compounds and certain physicochemical and biochemical properties such as hydroxymethylfurfural (HMF) and color in a chemometric approach. In this study, a total of 41 local honey samples were analyzed. The levels of elements Al, As, B, Cd, Cr, Cu, Fe, Mg, Zn, and Pb were determined by inductively coupled plasma optical emission spectrophotometer (ICP-OES). The mean concentrations of the elements in the samples were identified as 3.09, 0.64, 59.07, 0.02, 0.14, 0.17, 1.76, 9.32, 0.78, and 0.33 µg/g for Al, As, B, Cd, Cr, Cu, Fe, Mg, Zn, and Pb, respectively. The mean bioactive compounds of the honey samples were determined as phenolic content (19.74 mg GAE/100 g), flavonoid content (4.47 mg CE/100 mg), and DPPH (49.08% inhibition). The HMF levels of all samples conformed to the honey standards of the Codex Alimentarius and Turkish Food Codex. HMF was not negatively correlated with the other color parameters except for the a* (redness or greenness) value. This study showed that clustering analysis (CA) and principal component analysis (PCA) are useful for distinguishing the originality of honey samples by using element content, bioactive properties, HMF, and color and were useful in defining the Kars honey type. [ABSTRACT FROM AUTHOR]

5-Hydroxymethylfurfural (HMF) is a versatile platform chemical derived from the dehydration of renewable carbohydrates (typically glucose/fructose-based monosaccharides, oligosaccharides, and polysaccharides). Some useful compounds, such as 2,5-furandimethanol (FDM), 2,5-dimethylfuran (DMF) and 2,5-dimethyltetrahydrofuran (DMTHF), have been synthesized by reduction of HMF. Among these, FDM is a promising diol and can be further converted towards fine chemicals, liquid fuels and polymer materials. In this review, some typical catalytic systems for the synthesis of FDM from both HMF and carbohydrates were summarized. The discussion focused on controlling the reaction networks for the reduction of HMF. The reaction mechanisms and the stability of the catalysts were introduced briefly. Last but not least, the prospects of effective production of FDM were discussed as well. [ABSTRACT FROM AUTHOR]

In this research, iota carrageenan (ιC) was cross-linked with N, N-methylene bisacrylamide (MBA) to form ιC-g-MBA, as a new green solid acid catalyst. The catalyst structure and morphplogy were explored using FT-IR, TGA, BET, FESEM, and XRD techniques. It was used in 5-hydroxymethylfurfural (5-HMF) production by fructose and glucose dehydration. Factors contributing to reaction optimization, such as the solvent, temperature, catalyst amount, and reaction duration, were explored. The optimal conditions of the reaction for fructose dehydration were 160 °C and 1 h as the reaction temperature and time, respectively. It was established that the conversion of fructose and HMF yield was 95.5% and 93.1%, respectively. Similarly, the optimal temperature and time for the reaction of glucose dehydration were 160 °C and 2 h, respectively. Moreover, the HMF yield and glucose conversions were 46% and 93%. Reusability of the catalyst was analyzed, whereupon the catalyst proved capable of being reemployed after four runs. [ABSTRACT FROM AUTHOR]

Developing sustainable, inexpensive material has been proposed as a promising catalyst. Herein, we report the synthesis of new hybrid material composed of carbon nanoparticles entrapped in iron vanadate. Thus obtained new material was characterized using SEM, PXRD, Raman and XPS.The catalytic potentiality of CNP/FeVO4 has been tested in the oxidation of biomass derived hydroxymethylfurfural (HMF) in an aqueous medium. An enhanced conversion of 5‐HMF to diformylfuran (DFF) is observed in the presence of CNP/FeVO4 than FeVO4 alone. The absence of expensive metals and using only water as a solvent, along with recyclability of catalyst make our catalytic method green and attractive. [ABSTRACT FROM AUTHOR]

[Display omitted] • Solvent polarity and basicity effect on fructose selective conversion was discussed. • High polarity-low basicity solvent was favorable for furfural formation. • High polarity-high basicity solvent promoted the HMF formation. • Solvents around fructose preferential arrangement caused the selective conversion. • High yields of furfural (76.2%, GBL-H 2 O) and HMF (90.5%, DMSO-H 2 O) were obtained. Selective transformation of biomass-based feedstocks into value-added energy chemical is one of the most critical steps in biorefinery process. Herein, we gave insight into solvent effect on selective production of furfural or 5-hydroxymethylfurfural (HMF) from fructose with the combination of experiments, nuclear magnetic resonance (NMR) and molecular dynamics (MD) simulation. It was found that the selective formation of furfural and HMF was mainly dominated by solvent polarity and basicity, and solvent properties could change the reaction pathway of fructose. High polarity-high basicity solvent promoted HMF formation, while high polarity-low basicity solvent was conductive to furfural formation. The preferential arrangement of solvents around fructose tautomers, especially on different C-OH, consequently led to the different products. High yields of furfural (76.2%) and HMF (90.5%) were obtained in the solvents of γ-butyrolactone (GBL)–H 2 O and dimethyl sulfoxide (DMSO)–H 2 O. [ABSTRACT FROM AUTHOR]

The quality evaluation and physicochemical parameters assessment of Slovak and Austrian monofloral honeys were performed. In total 65 local monofloral honeys denoted by beekeepers as acacia (n = 20), rapeseed (n = 10), linden (n = 10), honeydew (n = 6), forest (n = 12) and chestnut (n = 7) were collected. The parameters such as moisture content, water activity, electrical conductivity, pH, free acidity, and 5-hydroxymethylfurfural (HMF) content were assessed for physicochemical characterization and comparison of all monofloral honeys. Electrical conductivity showed to be the most significant indicator for honeydew origin, that together with pH and aw led to 81.54 % correct classification of samples according to honey type using multivariate statistical analysis. In context to undesirable fermentation and spoilage, aw value below 0.600 showed to be an important control parameter that could be recommended to control especially for creamed rapeseed honeys. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to make a breakfast spreadable Cornelian cherry nectar similar to marmalade. Lactiplantibacillus plantarum DA100 strain, which has potential probiotic properties, was added to this nectar. It was investigated whether this strain has an effect on various sensory properties of nectar. In the study, sensory and various chemical properties of nectar produced without probiotic microorganism were determined. Since the breakfast spreadable Cornelian cherry nectar produced in our study was not exposed to high temperatures for a long time, a very low HMF of 4.290 mg/kg was determined. Vitamin C was determined as 716.800 mg/L and total phenolic content was determined as 3156.64 mg GAE/100g. In the probiotic group, the microorganism viability, which was 1.5×1010 Log CFU/mL initially, was determined below approximately 1.5×106 Log CFU/mL at the end of 5 days. In addition, coliform bacteria and E. coli were not detected in any group during this period. Contrary to the texture score, the difference between the sensory evaluation results of the probiotic-added and the control group of breakfast spreadable Cornelian cherry nectar was significant in taste, bitterness, odor and sourness. An alternative to jams and marmalades, rich in vitamin C and phenolic content, limited HMF production, and a functional product with low sugar content were tried to be obtained, and when the results obtained are evaluated, the product is thought to be promising.

AIM. To assess cognitive dysfunction in clinical practice, depending on the task being solved in the examination, different neuropsychological research methods are used. To identify the specific cause of the dysfunctions in the structure of various mental functions (neuropsychological characteristics of the defect) and in the brain functions (topical diagnosis), methods of qualitative analysis of the detected symptoms of the disorder are used. Psychometric (quantitative) methods are used to assess numerically the severity of disorders and the dynamics of changes in the state of individual mental functions, as well as for screening assessment of e possible cognitive decline level in general. Methods of cognitive dysfunctions qualitative assessment are focused on the search for a «missing link» in the structure of the examined mental functions. Psychometric tests, in most cases, describe the general state of either individual mental functions, or, in the case of screening, a set of cognitive functions. Thus, one or more aspects of mental functions are evaluated, in which several cognitive functions are involved at once. The article presents the results of a literature review with a description and analysis of preferences, methods used and corresponding techniques for neuropsychological examination of cognitive disorders in domestic clinical practice in vascular brain lesions.

Bio-based renewable resources have emerged as strong contenders to produce fuels and chemicals via carbon–neutral and eco-friendly methods. In particular, 2,5 furandicarboxylic acid (FDCA) which is listed among the top 12 platform molecules, can be used to produce bio-based polymer as an alternative to polyethylene terephthalate (PET). Notably, FDCA can be produced from an array of biorenewable resources using catalytic materials. However, biomass-derived 5-hydroxymethylfurfural (HMF) remains the primary feedstock to produce FDCA. Thus, the current review focuses on the recent advances in FDCA application and production via catalytic routes, particularly from HMF and other biorenewable feedstocks. Accordingly, the effect of different noble metal and noble metal-free catalytic materials on feedstock conversion and FDCA yield has been discussed. Moreover, the effect of operating conditions such as solvent, bases, oxygen sources, temperature and pressure has been discussed.

The catalytic transformation of biomass-based furan compounds (furfural and HMF) for the synthesis of organic chemicals is one of the important ways to utilize renewable biomass resources. Among the numerous high-value products, cyclopentanone derivatives are a kind of valuable compound obtained by the hydrogenation rearrangement of furfural and HMF in the aqueous phase of metal–hydrogen catalysis. Following the vast application of cyclopentanone derivatives, this reaction has attracted wide attention since its discovery, and a large number of catalytic systems have been reported to be effective in this transformation. Among them, the design and synthesis of metal catalysts are at the core of the reaction. This review briefly introduces the application of cyclopentanone derivatives, the transformation mechanism, and the pathway of biomass-based furan compounds for the synthesis of cyclopentanone derivatives. The important progress of metal catalysts in the reaction since the first report in 2012 up to now is emphasized, the characteristics and catalytic performance of different metal catalysts are introduced, and the critical role of metal catalysts in the reaction is discussed. Finally, the future development of this transformation process was prospected. [ABSTRACT FROM AUTHOR]

Honey is an excellent alternative to be used in different applications by the food, pharmaceutical, and cosmetics industries. However, the use of honey in its liquid form can present several disadvantages due to its high viscosity and density. In addition, honey can naturally crystallize during storage time, limiting its application in new products by industries. Thus, an alternative to using liquid honey in industry is the powder form. The objective of this study was to obtain honey powder by spray drying using a plant-based protein as a carrier. The honey used as raw material showed acceptable physicochemical parameters by the legislation of honey quality control, such as pH of (4.0 ± 0.1), the water content of (20.70 ± 0.3) g/100 g, ash of (0.48 ± 0.02) g/100 g, the fructose content of (35.42 ± 0.14) g/100 g, (43.05 ± 0.46) g/100 g for glucose, (0.56 ± 0.02) g/100 g for sucrose, and 5-hydroxymethylfurfural (HMF) value of (37.47 ± 1.04) mg/kg of honey, leading to the production of the honey powder. The mixture of fresh honey and plant-based protein was made with dispersions of 15, 16 and 18 g/100 g of honey using isolated rice protein as a carrier (total solid at 30 g/100 g d.b.). Finally, the honey powder produced was physicochemically characterized. The dispersion with 16 g/100 g of honey achieved an intermediary sugar/honey recovery of 35.93 ± 0.82% and 68.54 ± 2.16% of total protein recovery, and the spray drying yield was satisfactory > 50%. The overall results suggested that this dispersion is the ideal formulation when commercialization of the honey powder as an ingredient is intended. [ABSTRACT FROM AUTHOR]

Poly(propylene carbonate) (PPC) is gaining significant momentum as a biodegradable polymer using CO2 as an abundant, low-cost and renewable feedstock. Yet, PPC suffers from unsatisfactory thermal and mechanical properties, and its blends with other synthetic polymers as the second component typically exhibit poor compatibility. Herein, novel furan-based non-isocyanate polyurethanes (NIPUs) with high molecular weights and narrow distributions have been synthesized starting from 5-hydroxymethylfurfural (HMF) via a four-step procedure including reduction, glycidylation, carbonation of CO2 and step-growth polymerization with diamines. Owing to the structural similarity and intermolecular hydrogen bonding interactions, furan-based NIPUs display good compatibility with PPC. A sea-island morphology can be observed in SEM images of PPC/NIPU blends, where the NIPU phases are randomly dispersed in the PPC matrix. Moreover, the blends exhibit only one Tg (higher than both that of PPC and the corresponding NIPU) on the DSC curves, which first increase and then decrease when increasing the content of NIPUs from 0 wt% to 15 wt%. Notably, the physical crosslinking formed by hydrogen bonding interactions, coupled with the rigidity of furan rings, confer simultaneous improvements of elongation at the break and tensile strength, affording high-performance CO2-based biodegradable polymeric materials with low carbon footprint, good sustainability, and ideal biocompatibility. [ABSTRACT FROM AUTHOR]

In the present research, we report on an innovative and quick procedure for the synthesis of metal oxides: a sol-gel procedure which is followed by two steps that are assisted by microwaves (MW) heating. First, MW heating promotes gel drying and successively permits the calcination of the xerogel in a few minutes, using a susceptor that rapidly reaches high temperatures. The procedure was employed for the synthesis of zirconium dioxide (ZrO2), and MW-assisted calcination enables the collection of tetragonal ZrO2, as confirmed by different experimental techniques (PXRD, HR-TEM and Raman spectroscopy). Using this MW-assisted sol-gel procedure, a promoted sulphated zirconia (SZ) has been obtained. Both the nature and strength of SZ surface acidity have been investigated with FTIR spectroscopy using CO and 2,6-dimethylpyridine (2,6-DMP) as probe molecules. The obtained materials were tested as catalysts in acid hydrolysis of glucose to give 5-(hydroxymethyl)furfural (5-HMF). One of the obtained catalysts exhibited a better selectivity towards 5-HMF with respect to SZ material prepared by a classical precipitation route, suggesting that this procedure could be employed to obtain a well-known catalyst with a less energy-consuming procedure. Catalytic results also suggest that good selectivity to 5-HMF can be achieved in aqueous media in the presence of weak Lewis and Brønsted sites. [ABSTRACT FROM AUTHOR]

Copyright of Harran Journal of Agricultural & Food Science is the property of Harran University, Faculty of Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Seven commercially processed and two unprocessed honey samples of different origins were evaluated for their physicochemical, biochemical and anti-oxidant properties. The initial values of the different parameters varied significantly (p < 0.05) and ranged as follows: pH, 3.65 - 4.16; colour intensity, 103 - 1029 mAU; HMF, 1.00 - 58.85 mg/kg; proline, 34.51 - 520.11 mg/kg; phenolic, 32.48 - 86.73 mg GAE/100g; flavonoid, 2.27 - 9.73 mg QE/100g; IC50, 90.00 - 198.95 mg/mL. Except proline, the different parameters tested were found to conform to the values set by the Codex Alimentarius Commission (2002). The impact of thermal treatment was also investigated on the physicochemical and biochemical parameters. The results showed a tremendous increase in the HMF in samples originated from Mauritius (4) and India (8) as the temperature was increased which may be an indication of adulteration while the proline content showed a decrease for all the samples compared to their initial values. Anti-oxidant properties of the honey samples were found to increase and showed strong correlation with the phenolics, flavonoids and colour intensity. No significant variation was observed in the different parameters of the honey samples stored for 3 months after opening except for HMF value for sample 4. [ABSTRACT FROM AUTHOR]

In this study, the number of beekeepers staying within the borders of Denizli province, which is one of the important accommodation centers of wandering beekeepers with its large thyme fields, and their accommodation places were determined and some information about thyme honey was obtained. Especially in Gözler, Uzunpınar, Belenardıç and Güzelpınar neighborhoods of Pamukkale district and Yağcılar neighborhoods of Güney district, thyme fields are dense and approximately 24 thousand bee hives stayed in 2021. Some physicochemical analyzes were carried out, for example, 9 honeys in 2021 and 6 honeys in 2022, which were collected in July when the Denizli thyme honey produced in these areas was harvested. First, pollen analysis was made in honey samples, and it was determined that it was thyme honey. Then, proline, diastase activity (DA), moisture, electrical conductivity (EC), pH, free acidity (FA), HMF, fructose (F), glucose (G), total phenolic content (TPC) was determined in 15 honey samples. Average amount of proline in thyme honey samples in 2021 and 2022, respectively; 663.5 and 708.9 mg/kg, DA 10.9 and 11.75; humidity rates 17.1% and 17.3%; EC 560 and 540 µS cm-1 ; pH 3.8 and 3.8; FA; 26.4 and 28.8 meq.kg-1 ; HMF, 9.5 and 12.4 mg/kg; F+G 69.6% and 69%; F/G was determined as 1.13 and 1.10, and the TPC was determined as 75.9 mg GAE/100g. In the future, it will be possible to reveal the descriptive features of Denizli thyme honey from other honeys by conducting more comprehensive and advanced analyzes. [ABSTRACT FROM AUTHOR]

In this work, a deep eutectic solvent (DES) composed of choline chloride (ChCl) and ethylene glycol (EG) was prepared and applied for the conversion of fructose to 5-hydroxymethylfurfural (HMF), catalyzed by HCl in both laboratory batch reactors and continuous flow microreactors. The effects of reaction temperature, batch time, catalyst loading and molar ratio of ChCl to EG on the fructose conversion and HMF yield were first investigated in the monophasic batch system of ChCl/EG DES. To inhibit HMF-involved side reactions (e.g., its polymerization to humins), methyl isobutyl ketone (MIBK) was used as the extraction agent to form a biphasic system with DES in batch reactors. As a result, the maximum HMF yield could be enhanced at an MIBK to DES volume ratio of 3:1, e.g., increased from 48% in the monophasic DES (with a molar ratio ChCl to EG at 1:3) to 63% in the biphasic system at 80°C and 5 mol% of HCl loading. Based on the optimized results in batch reactors, biphasic experiments were conducted in capillary microreactors under slug flow operation, where a maximum HMF yield of ca. 61% could be obtained in 13 min, which is similar to that in batch under otherwise the same conditions. The slight mass transfer limitation in microreactors was confirmed by performing experiments with microreactors of varying length, and comparing the characteristic mass transfer time and reaction time, indicating further room for improvement. Highlights: • The efficient fructose conversion to HMF in deep eutectic solvents was achieved in batch reactors and microreactors. • An HMF yield over 60% could be obtained at a fructose conversion above 90% in both reactors at 80°C within 14 min. • The HMF yield was enhanced from 48% in the monophasic ChCl/EG system to 63% in the DES-MBIK biphasic system in batch. • A slight mass transfer limitation was found in the biphasic slug flow microreactor. [ABSTRACT FROM AUTHOR]

The direct conversion of glucose to 5-(hydroxymethyl)furfural (HMF) has been considered a challenging process. In this study, we developed a new method using gadolinium(III) trifluoromethanesulfonate (Gd(OTf)3) in combination with Brønsted acidic ionic liquids as a catalytic system to search possibly more environmentally benign process. The reaction was carried out under a continuous-flow system. The one-step isomerization/dehydration of glucose to give the highest HMF with Gd(OTf)3 together with DBU-based Brønsted acidic ionic liquid in a low-cost home-built continuous system. The plausible mechanism was proposed with the Lewis acidic sites of Gd(OTf)3 for the isomerization step and DBU-based Brønsted acidic ionic liquid sites for the dehydration step. The recycling of catalytic system Gd(OTf)3/DBU-based Brønsted acidic ionic liquid in DMSO was examined. Our findings provided a safe and environmental process for the continuous conversion of glucose into HMF. The use of continuous flow for HMF synthesis ensures that the current method can be applied to the large-scale process. [ABSTRACT FROM AUTHOR]

A simple and sensitive electrochemical sensor based on bismuth film that was coated onto a carbon paste electrode was prepared and used for hydroxymethylfurfural (HMF) detection. It was observed that bismuth film electrode (BiFE) greatly accelerated the electron transfer rate and showed excellent electrochemical activity for the oxidation of HMF compared to bare electrode. The effects of bismuth concentration, deposition potential, and deposition time on the responses of BiFE for the detection of HMF were optimized. As an analytical characteristic parameter, oxidation peak current was linearly related to HMF concentration in the range of 0.01 μM to 40 μM with a limit of detection value of 0.363 μM. Also, when selectivity studies were conducted, it was observed that BiFE had no interfering effect in the presence of three fold concentrations of coexisting similar structures compared to that of HMF. Moreover, the proposed method was successfully applied for the sensitive determination of HMF in various food samples with satisfactory recoveries. [ABSTRACT FROM AUTHOR]

The production of polymers from lignocellulosic biomass is currently one of the challenges to minimizing dependence on fossil fuels such as oil. The cellulosic fraction of this feedstock can be transformed into simple sugars such as glucose or fructose. These sugars can be further converted into 2,5-furandicarboxylic acid (FDCA), a precursor of polyethylene furanoate (PEF). The dehydration of sugars to 5-hydroxymethylfurfural (HMF), a platform molecule to obtain products of interest, has been extensively studied. In addition, the oxidation of this platform molecule to FDCA has been widely investigated. However, a study of the direct or one-step production of FDCA from sugars is needed. This review provides a general overview of the recent research on the catalytic systems for the direct production of FDCA from sugars. Ideally, a single-stage system should be employed. The investigations carried out in a one-step process are first detailed. Different strategies have been tested, such as the physical separation of two phases, where dehydration and oxidation took place separately. In this case, an efficient transfer of HMF is needed. To avoid HMF transfer limitations, other authors focused on the investigation of the one-pot transformation of HMF without physical separation. The major requirement of these processes is to achieve catalytic systems functional for both dehydration and oxidation reactions. Therefore, other investigations focused on the study of two-step integrated systems are also analyzed in this review. [ABSTRACT FROM AUTHOR]

Building blocks with amine functionality are crucial in the chemical industry. Biocatalytic syntheses and chemicals derived from renewable resources are increasingly desired to achieve sustainable production of these amines. As a result, renewable materials such as furfurals, especially furfurylamines like 5-(hydroxymethyl)furfurylamine (HMFA) and 2,5-di(aminomethyl)furan (DAF), are gaining increasing attention. In this study, we identified four different amine transaminases (ATAs) that catalyze the reductive amination of 5-(hydroxymethyl)furfural (HMF) and 2,5-diformylfuran (DFF). We successfully immobilized these ATAs on glutaraldehyde-functionalized amine beads using multiple binding and on amine beads by site-selective binding of the unique Cα-formylglycine within an aldehyde tag. All immobilized ATAs were efficiently reused in five repetitive cycles of reductive amination of HMF with alanine as co-substrate, while the ATA from Silicibacter pomeroyi (ATA-Spo) also exhibited high stability for reuse when isopropylamine was used as an amine donor. Additionally, immobilized ATA-Spo yielded high conversion in the batch syntheses of HMFA and DAF using alanine (87% and 87%, respectively) or isopropylamine (99% and 98%, respectively) as amine donors. We further demonstrated that ATA-Spo was effective for the reductive amination of HMF with alanine or isopropylamine in continuous-flow catalysis with high conversion up to 12 days (48% and 41%, respectively). [ABSTRACT FROM AUTHOR]

In commercially available honey, the application of a heat treatment to prevent spoilage can potentially compromise its beneficial properties and quality, and these effects worsen with extended storage. The high-pressure processing (HPP) of honey is being explored, but its long-term impact on honey quality has not been characterised yet. This study evaluated the effects of HPP and thermal processing on the microbial load, physicochemical quality (i.e., hydroxymethylfurfural content and diastase activity), and antioxidant capacity of honey after treatment and following extended storage (6, 12, and 24 months) at 20 °C. Pasteurization (78 °C/6 min) effectively eliminated the microorganisms in honey but compromised its physicochemical quality and antioxidant activity. HPP initially showed sublethal inactivation, but storage accelerated the decrease in yeasts/moulds and aerobic mesophiles in honey (being Apis mellifera honey, with a minimal risk of a loss of antioxidant activity compared to traditional industrial honey pasteurization.

Ohmic heating (OH) is an electrothermal technology used to inactivate enzyme and microbial activities. This work aimed to study the impact of Ohmic Heating Under Vacuum (OHUV) which compared to conventional heating (CH) as well as storage stability at 5°C and 25 °C on microbial safety, and nutritional quality. The evaluation parameters were pH, titratable acidity, TSS, lycopene, ascorbic acid, PME, HMF, and microbiological activity. The obtained results showed that tomato paste samples that were treated by OHUV are significantly superior to CH in terms of all physicochemical and microbiological characteristics, as well as being the least harmful during storage in both transparent and dark packages. The results showed the changes in ascorbic acid, lycopene, and HMF values that were treated by OHUV at 25 °C and filled in transparent package are most affected compared to other treated samples. On the other hand, tomato paste samples stored in dark packages at 5 °C performed significantly better than those subjected to CH under the same conditions and activated PME the most had higher ascorbic acid and lycopene and fewer changes in HMF during storage time for 90 days. OHUV found to be a good alternative treatment in the production of tomato paste.

The aim of the study is to be determine the effect of lactose hydrolysis and sugar content on physicochemical properties, sensory profile and HMF (5-hydroxymethylfurfural) content in Dulce de Leche (DL). Lactose free (lactose-hydrolysed) dairy products as well as low sugar products have been developed to supply consumer demand. Two different sucrose concentrations, 16% and 20%, were used in milk jam samples produced by the traditional method. For the formation of desired colour and flavour in the Dulce de Leche, Maillard reaction products are mainly responsible. HMF is Maillard reaction indicator analysed in this work. Fat, protein, solid content, ash, lactic acid and pH analysis were carried out. Sucrose, glucose, fructose and lactose concentrations were determined. Lightness, yellowness and redness as colour parameters of DL samples were evaluated and sensory analyses were also performed. It has been revealed that lactose hydrolysis causes significant changes in the color parameters and sensory profile of the samples. In this study, less or no HMF was detected in the lactose hydrolyzed DL samples compared to the control samples.

Abstract The determination of hydroxymethylfurfural (HMF) in bee honey is performed by the spectrophotometric methods Winkler's and White's. The Winkler method reads the absorbances in the visible region of the spectrum, and the White method measures in the ultraviolet (UV) and visible regions of the spectrum. This study aims to compare the spectrophotometric methodologies of White and Winkler to the determination of HMF in bee honey. For the study, it was used a UV-visible spectrophotometer, 10 mm optical path quartz cuvettes, and ten bee honey samples of different flowering. Absorbances at 550 nm were analyzed by the Winkler method; absorbances at 284 nm and 336 nm in the White method; and a comparison of HMF concentration (mg/kg) was carried out between the methods. The results showed significant differences (p

Introduction: Extrauterine growth retardation (EUGR) is one of the major problems faced in most preterm neonates. The only way to prevent EUGR is by providing adequate amount of calories through fortification of human breast milk. Human milk fortification (HMF) is now considered a standard practice to prevent EUGR in most of the neonatal units. We compared targeted individualized fortification (TIF) versus standardized fortification (SF) of breast milk with HMF to assess catch‑up growth in preterm neonates. Materials and Methods: We conducted a prospective randomized control study at a tertiary neonatal intensive care unit in urban India for 1 year. Appropriate for gestational age neonates ≤32 weeks of gestation or with birth weight ≤1800 g were enrolled and followed up for 50 corrected weeks for the assessment of catch‑up growth. Results: A total of 32 infants were enrolled; 25 neonates completed the study (TIF: n = 13; SF: n = 12). The mean birth weight and head circumference were 1268.76 g and 27.23 cm in the TIF group and 1172.83 g and 26.58 cm in the SF group, respectively (both P > 0.05). At the end of the study, catch‑up growth for weight was achieved by 10 (77%) neonates in the TIF group and 2 (17%) neonates in the SF groups. Similarly, catch‑up growth for head circumference was achieved by 7 (54%) and 1 (8%) neonates in the TIF and SF groups, respectively. However, there was a significant difference in weight (P = 0.00071) and head circumference (P = 0.001752) in the TIF group at the end of the study. Conclusion: TIF is feasible in clinical practice. In preterm neonates, it helps in achieving catch‑up growth faster and may decrease the rates of EUGR. [ABSTRACT FROM AUTHOR]

The ability of additives to reduce the formation of acrylamide in simulated sugar cane syrups was investigated. Organic acids, B vitamins, and inorganic salts were added individually and in combination to simulated thickened cane juice, and the mixtures were heated at 120 °C for 30 min. Calcium chloride (1%), citric acid (0.1%), and vitamin B3 (0.1%) were the most effective individual additives from each chemical family. The effects of CaCl2 (0–1%), citric acid (0–0.125%), and vitamin B3 (0–0.1125%), when added in combination, on the concentrations of acrylamide and hydroxymethylfurfural (HMF) were studied using a Box–Behnken design. Combinations of all three additives lowered the acrylamide production, but only the combination of citric acid and vitamin B3 had a significant synergistic effect. However, all these additives stimulated the production of HMF, and no significant interactive effect between pairs of additives on HMF production was observed. Calcium chloride stimulated the formation of HMF most strongly. These results indicate that certain combinations of these additives effectively reduce acrylamide formation, but they also lead to an increase in the formation of HMF in sugar syrup. [ABSTRACT FROM AUTHOR]

In the present study, different ratios (5%, 7.5%, 10%) of strawberry puree added to buffalo yoghurt produced using ABT-2 probiotic culture were investigated in terms of fatty acid composition, ACE inhibitor activity and HMF content. In addition, the effects of fruit addition and storage period on physicochemical, microbiological, and sensory analyses of yoghurt samples were investigated. It was determined that the addition of strawberry puree to buffalo yoghurt had a very significant (P < 0.01) effect on all fatty acids, ACE inhibitor activity, HMF content, physicochemical, microbiological and sensory analyses except for the minor polyunsaturated fatty acids. While it was determined that total saturated fatty acids and ACE inhibitor activity levels decreased with the addition of fruit, an increase was found in HMF content, total monounsaturated fatty acids and total polyunsaturated fatty acids. As a result of this research, consumption of buffalo yoghurt as a functional food can be recommended. [ABSTRACT FROM AUTHOR]

Replacing fossil-based polymers with renewable bio-based polymers is one of the most promising ways to solve the environmental issues and climate change we human beings are facing. The production of new lignocellulose-based polymers involves five steps, including (1) fractionation of lignocellulose into cellulose, hemicellulose, and lignin; (2) depolymerization of the fractionated cellulose, hemicellulose, and lignin into carbohydrates and aromatic compounds; (3) catalytic or thermal conversion of the depolymerized carbohydrates and aromatic compounds to platform chemicals; (4) further conversion of the platform chemicals to the desired bio-based monomers; (5) polymerization of the above monomers to bio-based polymers by suitable polymerization methods. This review article will focus on the progress of bio-based monomers derived from lignocellulose, in particular the preparation of bio-based monomers from 5-hydroxymethylfurfural (5-HMF) and vanillin, and their polymerization methods. The latest research progress and application scenarios of related bio-based polymeric materials will be also discussed, as well as future trends in bio-based polymers. [ABSTRACT FROM AUTHOR]

This study aims to perform kinetic and thermodynamic analysis of subcritical water hydrolysis (SWH) of bakery leftovers. Hydrolysis kinetics of leftover croissants (LC) and leftover doughnuts (LD) into monosaccharides and by-product (hydroxymethylfurfural, HMF), via subcritical water hydrolysis, were studied in temperature range of 100 to 240°C for 6 to 30 minutes and solid loading of 10% (w/v). The monosaccharides yield increased from 100 to 200°C, but it decreased when the temperature further increased from 220–240°C due to degradation of monosaccharides into its by-product (HMF). The activation energy (Ea) monosaccharides degradation was higher than its formation: 104.87 and 88.55 kJ/mol (LC) and 104.69 and 75.72 kJ/mol (LD). The positive values of ΔG# signified that the SWH for sugar recovery from LC and LD is an endergonic reaction. [ABSTRACT FROM AUTHOR]

Featured Application: This study provides key factors for the efficient subcritical low-acid hydrolysis of oligosaccharides from red seaweed having potential prebiotic properties, a sought-after functional food ingredient. Extraction of marine oligosaccharides from sustainable seaweed biomass with minimal loss is a green effort to cater to the huge global functional food demand. Seaweed is a sustainable source of marine oligosaccharides that potentially could be used as a prebiotic ingredient for functional food development. The study aims to optimize the oligosaccharide preparation through thermal hydrolysis of an under-utilized red seaweed, Eucheuma denticulatum. Response surface methodology (RSM) applying Box–Behnken design (BBD) was used on three parameters including temperature (105–135 °C), hydrolysis time (15–35 min) and sulfuric acid concentration (0.05–0.2 M). Optimized fractions with good prebiotic activity were characterized using high-performance size-exclusion chromatography (HP-SEC) and Fourier transform infrared spectroscopy (FT-IR). Eucheuma denticulatum oligosaccharides fraction 1 (ED-F1) was shown to promote the growth of beneficial gut microbiota including Lactobacillus plantarum, L. casei, L. acidophilus, Bifidobacterium animalis and B. longum with the highest prebiotic activity score of 1.64 ± 0.17. The optimization studies showed that hydrolysis time was the most significant parameter for the oligosaccharides yield. Optimal hydrolysis conditions for ED-F1 were 120 °C, 21 min, 0.12 M H2SO4 with the highest yield achieved (11.15 g/100 g of dry weight). The molecular weight of ED-F1 was determined at 1025 Da while FT-IR analysis revealed the presence of sulfated oligosaccharides with similar characteristics of i-carrageenan. These findings signify the innovative method for the efficient production of seaweed derived prebiotic oligosaccharides, which could be a promising source of functional food ingredients for the development of health foods and beverages. [ABSTRACT FROM AUTHOR]

The increasing demand for sustainable alternatives to petroleum-based chemicals has driven research towards the utilization of renewable feedstock, such as lignocellulosic biomass (LCB), to produce high-value products. Among LCB-derived platform molecules, 5-hydroxymethylfurfural (HMF) has become a key building block for bio-based monomers such as 2,5-furandicarboxylic acid (FDCA), among many others. This study reports the successful synthesis of various Pt-Bi catalysts supported on activated carbon (C) and investigates their role in the HMF conversion to FDCA. The catalytic performance of the Pt-Bi/C catalysts was evaluated in batch reactors, using HMF in an aqueous reaction medium, with 1 M of Na 2 CO 3 to provide alkalinity, and under 10 bar of O 2. These results demonstrated a strong correlation between catalyst properties and their catalytic activity. Among the prepared catalysts, the 9Pt-3Bi/C catalyst was the most efficient one, achieving a yield to FDCA of 99.7 %. Further investigations revealed that the 9Pt-3Bi/C catalyst maintained its excellent performance even under reduced reaction times, lower temperatures, and reduced catalyst loadings, demonstrating its potential for practical applications. Across all reactions, it was observed that, under the tested reactions conditions, the existence of side reactions involving HMF degradation to other compounds was significant. This underscores the challenge of achieving quantitative HMF conversion to FDCA, enhancing the importance of catalyst properties and reaction conditions optimization to minimize by-product formation. [Display omitted] • Pt-Bi/C catalysts efficiently convert HMF to FDCA, with 9 Pt-3Bi/C yielding 99.7 %. • The 9 Pt-3Bi/C catalyst presents good performance at mild reaction conditions. • HMF degradation side reactions remain a challenge for full FDCA conversion. • Optimization of catalyst properties is key to minimising by-products. • Pt-Bi/C catalysts show potential for practical, sustainable applications. [ABSTRACT FROM AUTHOR]

Abstract 5‐hydroxymethylfurfural (HMF) is the object of extensive research in recent times. The challenge in the industrial production of HMF is the choice of cheap, hexose feedstock. This study compares continuous HMF synthesis from hexoses—fructose and glucose, and biomass—Miscanthus × giganteus and chicory roots. The experiments were conducted in technical‐scale biorefinery (TRL 6/7). In the first stage, optimal conditions for the production of HMF from hexoses were selected using sulfuric acid as a catalyst in an aqueous medium. The following conditions were chosen for fructose: temperature of 200°C, the reaction time of 18 min, and pH = 2, and for glucose: 210°C, 18 min, and pH = 3. Under these conditions, the HMF yield was 56.5 mol% (39.6 wt.%) from fructose and 18.1 mol% (12.6 wt.%) from glucose. From the biomass, the HMF yields were 36.7 and 16.2 wt.% for miscanthus and chicory roots, respectively. Some results from the conversion of biomass solutions are unexpected and show a need for further investigations. This work has demonstrated the capacity to produce HMF from biomass as part of an environmentally friendly process in a biorefinery. Further research in this field and process optimization will be a step forward in the sustainable production of bioplastics.

In order to meet the influent water quality of reverse osmosis membrane (RO) or nanofiltration membrane (NF) in the water reuse system of printing and dyeing wastewater, and to cope with the impact of actual printing and dyeing wastewater quality and water quantity, a new type was developed and submerged high-strength membrane filtration (HMF) technology for wastewater treatment compared with the traditional membrane bioreactor (MBR) technology. The combined effect of the process was investigated. The results show that compared with the traditional MBR technology, the membrane flux increased from 11~13 L/ (m2·h) to 14~16 L/ (m2·h), and the reflux rate is reduced from 250%~300% to 20%. The water quality of the HMF process is better than that of the MBR process, especially suspend solid, as low as 1 mg/L, which effectively guarantees the influent requirements of the subsequent RO/NF. The pollution level is relatively low, which is conducive to long-term stable operation. At present, the technology has been demonstrated and applied in the advanced treatment of wastewater in the printing and dyeing industry, and has a good promotion prospect.

• Hollow CdS quantum dots interact with MIL-101 to accelerate ·O 2 - generation. • 70 % CdS QDs/MIL-101 exhibits the best performance in photocatalytic oxidation of HMF to DFF. • The process of photocatalytic HMF oxidation was explored. • The photocatalytic mechanism of CdS QDs/MIL-101 for the conversion of HMF to DFF is proposed. 5-hydroxymethylfurfural (HMF) can catalyte into 2,5-diformylfuran (DFF) which had received much attention as a potential biomass resource. Here, we used a simple and effective method to construct hollow CdS quantum dot (CdS QDs)/MIL-101 heterostructures with high contact area and multiple active sites. The structure of heterostructures could improve photocatalytic activity by charge transfer, photogenerated carrier separation and the multiple refractions of light supported within the hollow-structured CdS QDs. The detailed catalytic mechanism was illustrated by trap agent experiments and electron paramagnetic resonance (EPR) spectroscopy, in which superoxide radicals (·O 2 -) play a decisive role in the catalytic oxidation of HMF to DFF. Furthermore, the large specific surface area of MIL-101 adsorbs O 2 from the reaction system thereby accelerating the ·O 2 - formation process. Under environmental conditions, 70 % CdS QDs/MIL-101 exhibited optimal catalytic performance. Comparing with pure CdS QDs, the photocurrent enhances 1.8 times, HMF conversion is 1.5 times and DFF selectivity is 1.2 times. This work provide a useful way to improve the conversion of biomass by Z-heterostructures under ambient conditions. Oxidation of 5-hydroxymethylfurfural to 2,5-dicarbonylfuran catalysed by CdS QDs/MIL- [Display omitted] [ABSTRACT FROM AUTHOR]

• The RuZS 90 displays good catalytic activity in water as a solvent with no external base, giving 67 % FDCA. • The NH 3 -TPD analysis indicates that RuZS 90 has 2.6 and 2.3 times higher total acidity than H-Z and RuH-Z. • The metallic Ru (77.6 %) in RuZS 90 predominantly contributes to HMF oxidation to FDCA compared to Ru on unmodified HZ (45.5 % metallic Ru). • NH 3 -DRIFT spectra exhibit that RuZS 90 contains more Lewis acidic sites than parent H-Z. • The poisoning study with potassium thiocyanate (KSCN) confirms the crucial role of Lewis acidic sites. The primary focus of the present study is to develop a zeolite-based catalyst that enhances Lewis acidity for catalysing 5-hydroxymethylfurfural (HMF) oxidation. The study modifies the parent H-ZSM-5 (H-Z) via desilication followed by Ru impregnation. The results show that RuZS 90 (Ru impregnated on desilicated H-Z for 90 min) exhibits higher catalytic activity for the HMF oxidation than Ru impregnated on parent H-Z. NH 3 -temperature programmed desorption (TPD) results indicate that RuZS 90 possesses more than 2.6 and 2.3 times higher total acidity than H-Z and RuH-Z, contributing to the higher catalytic activity. A poisoning study with potassium thiocyanate (KSCN), which passivates Lewis acidic sites, suggests that RuZS 90 yields no considerable oxidised furanic products, confirming the crucial role of Lewis acidic sites. The NH 3 -DRIFT study further corroborates that RuZS 90 contains more enhanced Lewis acidic sites than the parent H-Z, playing a vital role in the oxidation of HMF. Ru impregnated on modified H-ZSM-5 (RuZS 90), possessing enhanced Lewis acidic sites, exhibits about 20 and 3 times higher catalytic activity in terms of furanic products than parent H-ZSM-5 (H-Z) and Ru on parent H-ZSM-5(RuH-Z) due to the critical role of Lewis acidic sites. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Thermochemical biorefineries for the production of chemicals and materials can play an important role in the bioeconomy. However, their economic viability is often questioned under the premise of the economy of scale. This paper presents a regional, modular biorefinery concept for the production of the platform chemicals hydroxymethylfurfural (HMF), furfural and phenols from the lignocellulosic perennial miscanthus, which can be cultivated on marginal and degraded areas. The paper focuses on the question of the minimum selling price of HMF and the optimal plant size for this purpose, using the region of Baden‐Württemberg, Germany, as an example. Based on small pilot plant results, a scalable process simulation was created via AspenPlus. This allows different scenarios and process combinations of this multi‐output biorefinery concept to be compared with each other. Using this, a minimum sales price for the main product HMF is calculated using methods of dynamic investment cost calculation according to the net present value method. Based on this, the plant capacity was scaled. The scenarios and sensitivity analyses show that, with an accuracy of ±15%, regional biorefineries could already offer platform chemicals at prices of 2.21–2.90 EUR/kg HMF at the current stage of development. This corresponds to three to four times the price of today's comparative fossil base chemicals and is thus a competitive option from the authors’ point of view. The local biomass and the heat prices were identified as the main influencing factors. As a result, the selection of the location will have a decisive influence on the economic viability of such concepts in the case of further development and optimization of the process in first demonstration plants.

With an increasing demand for safe and natural products from both industries and consumers, paired with the recent ban of decried molecules (i.e. octinoxate, avobenzone or octocrylene) due to their high negative impact on humans and the environment (i.e. endocrine disruption, coral bleaching), safe bio-based alternatives are a necessary and promising surrogate to substitute current commercialized petroleum-based UV filters. In this context, a class of bio-based molecules, displaying interesting UV-B filtering properties and great photostability were developed from furfural and 5-hydroxymethylfurfural (HMF), using the Knoevenagel condensation with a set of green conditions to minimize the impact on environment. Furthermore, those furfural- and HMF-based molecules demonstrated antimicrobial properties as secondary activity, highly sought by industries. Some furan derivatives being recognized to exhibit toxicological risks, in silico and in vitro assays were conducted and demonstrated the absence of endocrine disruption activity for these new molecules. [ABSTRACT FROM AUTHOR]

BACKGROUND: 2,3‐Dihydro‐3,5‐dihydroxy‐6‐methyl‐4(H)‐pyran‐4‐one (DDMP) and 5‐hydroxymethylfurfural (HMF) are two main enolization products in the Maillard reaction and found in some foodstuffs. For many years, whether they are functional or noxious to human health has been a matter of debate. Thus, insight into their formation pathways is important to manage Maillard reaction products. In this study, DDMP and HMF were quantified and compared with regard to their formation and degradation in the d‐glucose and l‐proline Maillard reaction models using different moisture contents (0, 0.1, 0.5, 1.0, and 4.0 mL) at 150 °C for various heating times. RESULTS: DDMP was predominantly generated in dry or low water‐content heating models along with n increased 1‐deoxyglucosone (1‐DG) generation via 2,3‐enolization. However, increasing moisture content resulted in a decay of reaction intensity, 1‐DG, and DDMP due to a change in the reaction mechanism from 2,3‐enolization to 1,2‐enolization, which facilitated 3‐deoxyglucosone (3‐DG) and HMF formation. CONCLUSION: Increased moisture content in glucose–proline models reduced reaction intensity and also inhibited DDMP and facilitated HMF formation by promoting the pathway change from 2,3‐enolization to 1,2‐enolization to generate more 3‐DG. A water content of 1.0 mL was identified as a critical value, from which the 1,2‐enolization became a primary pathway occurring in the Maillard reaction. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this study, colorimetric parameters of the red color emerging as a result of the novel modified Seliwanoff test were used for the quantitative determination of HMF in some syrup samples. Three different evaluation method (color space-based method, absorbance method and artificial neural network (ANN)) were used to determine HMF amounts of samples. While "da*" and absorbance value of red color were used to obtain a linear relationship with HMF concentration, L*, a*, b*, dL*, da*, db*, dE* were used as input variables in artificial neural network evaluation. Also HPLC method was carried out as a reference method. In addition to the absorbance value, 'da*' value also showed a linear relationship with the HMF concentration (da* = 0.0425 + 0.0612 × HMF concentration, ppm); correlation coefficient: 0.9980; p value of lack of fit: 0.579). When HMF amounts obtained by each method were compared with that by reference method HPLC, a strong correlation was found (color space-based method-HPLC, r: 0.996; absorbance method-HPLC, r: 0.997 and ANN-HPLC; r: 0.997). Among the methods, ANN evaluation method was more prominent in detecting low HMF concentrations (< 4 mg HMF/kg sample). [ABSTRACT FROM AUTHOR]

The oxidation of 5-hydroxymethylfurfural (HMF) to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) has been investigated on MO x @Nb-zeolite catalytic systems (where MO x = CoO x , MnO x or FeO x and zeolite - USY and Beta) with hierarchical texture and acid-base properties. These catalysts were exhaustively characterized by several techniques such as XRD, adsorption-desorption of liquid nitrogen at 77 K, CO 2 - and NH 3 -TPD, DRIFT, XPS, and SS NMR. The new hierarchically catalysts produced HMFCA with a selectivity of 97.0% for a X HMF = 95.0% (Mn@Nb-Y30). A synergetic effect between MO x and Nb species in the activation of t -BuOOH and oxidation of HMF has been identified. The absence of FDCA in the reaction products using MOx@Nb-zeolite catalysts can be due to the preponderant presence of the acidic sites (associated to both framework and extra framework AlO x) which prevent a further oxidation of HMFCA to FDCA. [Display omitted] • Multifunctional hierarchically zeolites with non-precious metals. • Selective oxidation of HMF to HMFCA intermediate • The new combination of oxides avoids the use of homogeneous bases • Selective oxidation control through the AlO x framework [ABSTRACT FROM AUTHOR]

In this work, a green synthetic approach to 5,5′‐[oxybis(methylene)]bis‐2‐furfural (OBMF) from 5‐hydroxymethyl‐2‐furfural (HMF) is reported for the first time. In the optimized reaction conditions, dimethyl carbonate (DMC) is used as the preferred green solvent and iron(III) sulfate as the best catalyst, recyclable up to three times. The HMF self‐etherification reaction is conducted both in milligram‐ and gram‐scale with isolated yields up to 99% and 81% respectively. OBMF is further derivatized via reduction to achieve 5,5′‐oxybis(methylene)bis(furan‐5,2‐diyl)dimethanol (OBMF‐H), a potential bisphenol‐A biobased alternative. Thus, methoxycarbonylation of OBMF‐H leads to the biscarboxymethylated derivative (OBMF‐DC) employing, once again, DMC as solvent and reagent. Both OBMF‐H and OBMF‐DC are achieved in high yields and are fully characterized. Furthermore, thermogravimetric analysis of OBMF, OBMF‐H, and OBMF‐DC establishes that these compounds are more thermally stable than HMF and its derivatives. In fact, they can withstand up to 200 °C before undergoing complete degradation rendering OBMF and its derivatives valuable bio‐based monomers for bioplastics prepared via polycondensation reaction. [ABSTRACT FROM AUTHOR]

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