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In this study, a magnetically recoverable nano photocatalyst (Fe3O4/Fe2O3/TiO2/Ag) was prepared using Ag nanoparticles supported on anatase TiO2-coated Fe3O4/Fe2O3 nanoparticles. The photocatalyst was characterized by FT-IR, XRD, BET-BJH, ICP-AES, TEM, DLS, VSM, FESEM, and EDX and found to have excellent catalytic activity for synthesizing HMFCA (5-hydroxymethylfurfural-2-carboxylic acid) from HMF (5-hydroxymethylfurfural) in the presence of a deep eutectic solvent under white light irradiation. An appropriate HPLC method was established to obtain good separation of the possible metabolic substances. The advantages of this protocol consist of the use of a stable and safe light source, an environmentally friendly solvent, magnetic recyclability, and long-term stability of the catalyst for at least six consecutive runs. The synthesis of HMFCA using this method meets the requirements of green, sustainable synthetic chemistry and has potential applications in pharmaceutical chemistry and organic synthesis. Considering the yield of 98%, this novel protocol demonstrates a potential for one-pot synthesis of renewable HMFCA and a valuable product. Overall, this study showcases the advantages of green chemistry to make it a promising avenue for future research. [ABSTRACT FROM AUTHOR]

Quantum chemical methods have been intensively applied to study the pyrolytic conversion of glucose into hydroxymethylfurfural (HMF) and furfural (FF). Herein, we collect the most relevant mechanistic proposals from the recent literature and organize them into a single reaction network. All the transition structures (TSs) and intermediates are characterized using highly accurate ab initio methods and the possible reaction pathways are assessed in terms of the Gibbs energies of the TSs and intermediates with respect to β‐glucopyranose, selecting a 2D ideal‐gas standard state at 773 K to represent the pyrolysis conditions. Several pathways can lead to the formation of both HMF and FF passing through rate‐determining TSs that have ΔG‡ values of ~49–50 kcal/mol. Both water‐assisted mechanisms and nonspecific environmental effects have a minor impact on the Gibbs energy profiles. We find that the HMF → FF + CH2O fragmentation has a small ΔrxnG value and an accessible ΔG‡ barrier. Our computational results, which are in consonance with the kinetic parameters derived from lumped models, the results of isotopic labeling experiments and the reported HMF/FF molecular ratios, could be useful for modeling studies including on nonequilibrium kinetic effects that may render more information about product yields and the relevance of the various pathways. [ABSTRACT FROM AUTHOR]

Photocatalytic oxidation was a green and sustainable method for conversing the biomass derived platform molecule 5‐hydroxymethylfurfural (HMF) to high value‐added 2,5‐diformyfuran (DFF). In this work, both graphitized carbon nitride (g‐C3N4) and sulfur doped g‐C3N4 (S‐g‐C3N4) were fabricated, characterized and applied in the photocatalytic conversion of HMF. Accelerated separation of the photogenerated charge carriers was obtained on S‐g‐C3N4 with higher production of reactive oxygen species (ROS) including singlet oxygen (1O2) and superoxide radicals (⋅O2−), whereas relative higher HMF conversion rate and DFF selectivity were achieved on g‐C3N4. The mechanism investigation suggested that the contradictory phenomena may be caused by the stronger binding affinity of HMF on S‐g‐C3N4 compared with g‐C3N4 based on the temperature‐programmed desorption (TPD) measurement and theoretical calculation. The strong adsorption of HMF on the catalyst surface was unfavorable for desorption of the intermediates, and led to the accumulation of large number of carbon‐centered radicals. Part of these radicals may react with each other to generate polymerization products and block the active sites of the catalyst, resulted in the low conversion efficiency of HMF and DFF selectivity finally. This work provided a new sight and valuable theoretical and experimental basis for developing efficient photocatalysts for biomass conversion. [ABSTRACT FROM AUTHOR]

Liquid fuel, such as 2,5‐dimethylfuran (DMF), from biomass, is an efficient, potential alternative to fossil‐based fuels due to its exceptional properties, including lower volatility, a remarkable octane number, heightened energy density, and immiscibility with water. DMF can be the starting substrate for producing bio‐based p‐xylene through the Diels‐Alder reaction with ethylene to produce biobased polyethylene terephthalate (PET). This review, thus, discusses the catalytic role of various precious and non‐precious metals on different supports, such as carbon, metal‐oxide, zeolite, and hydrotalcite, for the production of DMF via catalytic hydrodeoxygenation (HDO) of 5‐hydroxymethylfurfural (HMF) based on the previously reported literature. Various characteristic properties of the employed catalytic materials, such as particle size, metal‐support and substrate interaction, surface area, porosity, and acidic and basic sites, are delineated, playing a crucial role in the HDO of HMF to DMF. The influence of various reaction parameters, such as hydrogen atmosphere, solvents‐ including hydrogen donor solvents‐ and temperature are also discussed. [ABSTRACT FROM AUTHOR]

Here, a series of nitrogen‐doped carbon (NC) supported transition metal oxide catalysts were prepared by pyrolysis of chitosan‐metal salt mixtures for the efficient synthesis 2,5‐diformylfuran (DFF) from 5‐hydroxymethylfurfural (HMF) and fructose. Among them, supported molybdenum‐based species on nitrogen‐doped carbon (Mo/NC) exhibited excellent activity and selectivity for selective oxidation of HMF to DFF. The presence of nitrogen species reduces the electron cloud density around the Mo species, thereby improving the catalytic activity. Moreover, the interaction between active MoO2 species on the catalyst surface and NC ensured the stability of the catalyst, resulting in no significant loss of activity after four catalytic cycles. 99.5 % and 55.1 % yields of DFF with full conversion were obtained from HMF and fructose respectively over Mo/NC‐chitosan‐600 in DMSO under ambient air. In order to enhance DFF yield from fructose, sulfonate groups were introduced into Mo/NC‐chitosan‐600 catalyst, leading to the highest DFF yield of 70.2 %. In addition, this catalyst also allowed 10.0%, 22.9% and 33.3% DFF yields from glucose, sucrose and inulin, respectively. [ABSTRACT FROM AUTHOR]

In this study, in order to verify the effects due to the addition of spirulina (Arthrospira platensis) in a food product, a wildflower honey was analyzed in terms of chemical composition, physicochemical properties and antioxidant activity before and after the addition of the spirulina. HS-SPME/GC–MS and HPLC/UV were applied to carry out the chemical analyses. The obtained results demonstrated that the volatile profile and also the sugar content were significantly influenced by the addition of spirulina, showing significant qualitative and quantitative differences compared to honey without spirulina. The increase in HMF in honey added with spirulina was significant, demonstrating that its presence could accelerate the Maillard reaction. Electrical conductivity measured by using a conductometer was also increased while the moisture content was reduced in honey enriched with spirulina. Instead, the pH value was similar between the two samples. On the other hand, honey fortification with spirulina determined a significant increase of 12.5% in the total phenolic content (TPC), and a 56.25% increase in protein content. Further, the total antioxidant capacity (TAC) was also evaluated and a significant increase was determined as a result of the addition of spirulina. In conclusion, honey enriched with A. platensis was found to be characterized by a high pool of bioactive metabolites as well as significant changes in almost all the measurements performed. [ABSTRACT FROM AUTHOR]

The development of biodegradable materials from biomass is a crucial strategy for leveraging biomass resources. A key component in this process is 2,5-bis(hydroxymethyl)furan (BHMF), a significant biomass-derived platform chemical. However, producing BHMF with high selectivity through the selective hydrogenation of 5-hydroxymethylfurfural, while avoiding the creation of unwanted byproducts, is a complex challenge. In our research, we have developed a novel catalyst featuring a magnetic core. This catalyst, which consists of platinum loaded onto a graphene-like shell, has been applied to the catalytic hydrogenation of HMF in an aqueous environment. Under the optimized conditions of 373 K, 3 MPa H2, and 1 h reaction time, a BHMF yield exceeding 99% was achieved. This method presents a promising and effective approach for the high-value conversion of biomass waste into polymer materials and pharmaceutical chemicals. [ABSTRACT FROM AUTHOR]

5‐Hydroxymethylfurfural (HMF) was transformed into 2,5‐diformylfuran (DFF) with nitric acid as the oxidant. The initial HMF content was as high as 12.5 wt %, and water was the sole solvent. This is an intensely exothermic reaction along with the emission of NO2 gas. A high DFF yield of 83.2 % was achieved if the oxidation ability of nitric acid matched with the requirement of target oxidation reaction while mismatched those of side reactions by regulating the initial concentration of nitric acid (59.5 wt %) and reaction temperature (50–60 °C). The oxidation reaction of HMF, overoxidation of HMF, and skeleton‐cracking reaction of FDCA preferred concentrated HNO3, hot HNO3, and concentrated or hot HNO3, respectively. After liquid‐liquid extraction, filtration, and column chromatography, light‐yellow DFF powders with purity of 92.1 wt % and isolated yield of 40.2 % were obtained and confirmed by NMR, FTIR, UV‐Vis, and elemental analysis. HMF was the dominant impurity due to its affinity to DFF. In addition, chromogenic substances were obtained as a byproduct, and they were potential pH indicators. These chromogenic substances had highly conjugated molecular structures, and they were generated via successive β‐protonation‐based ring‐opening reaction of HMF, aldol reaction, and dehydration reaction. [ABSTRACT FROM AUTHOR]

Foods contaminants pose a challenge for food producers and consumers. Due to its spontaneous formation during heating and storage, hydroxymethylfurfural (HMF) is a prevalent contaminant in foods rich in carbohydrates and proteins. Colorimetric assays, such as the Seliwanoff test, offer a rapid and cost-effective method for HMF quantification but require careful optimization to ensure accuracy. We addressed potential interference in the Seliwanoff assay by systematically evaluating parameters like incubation time, temperature, and resorcinol or hydrochloric acid concentration, as well as the presence of interfering carbohydrates. Samples were analyzed using a UV–Vis spectrophotometer in scan mode, and data obtained were validated using HPLC, which also enabled quantification of unreacted HMF for assessing the protocol's accuracy. Incubation time and hydrochloric acid percentage positively influenced the colorimetric assay, while the opposite effect was observed with the increase in resorcinol concentration. Interference from carbohydrates was eliminated by reducing the acid content in the working reagent. HPLC analyses corroborated the spectrophotometer data and confirmed the efficacy of the proposed method. The average HMF content in balsamic vinegar samples was 1.97 ± 0.94 mg/mL. Spectrophotometric approaches demonstrated to efficiently determine HMF in complex food matrices. The HMF levels detected in balsamic vinegars significantly exceeded the maximum limits established for honey. This finding underscores the urgent need for regulations that restrict contaminant levels in various food products. [ABSTRACT FROM AUTHOR]

Sulfonated carbons and commercial Amberlyst 15 and 45 served as model catalysts to explore the impact of the ratio between stronger and weaker acid sites (NS/NW) on 5‐hydroxymethylfurfural (HMF) and furfural production from fructose and xylose. Catalysts with varying structural and surface properties, and consequently different NS/NW ratios, were prepared from diverse templated mesoporous carbons and distinct sulfonation methods. HMF or furfural yields exhibited an exponential correlation with the NS/NW ratio. However, the catalytic activity per site (TON) displayed a volcano‐like plot, reaching a maximum between NS/NW=2–4. Consequently, our findings suggest the involvement of both strong (sulfonic acid) and weak acid (surface carboxylic acid, alcohol, and phenol groups) sites in monosaccharide dehydration mechanisms. These insights may guide the development of novel catalysts. [ABSTRACT FROM AUTHOR]

The thermotolerant yeast Pichia kudriavzevii (previously known as Issatchenkia orientalis), can produce ethanol from a variety of carbon sources and grows at around 45 °C. Thus, this yeast is considered a useful biocatalyst for producing ethanol from lignocellulose through simultaneous saccharification and fermentation (SSF). SSF has several advantages, such as a simplified manufacturing process, ease of operation and reduced energy input. Using P. kudriavzevii NBRC1279 and NBRC1664, we previously succeeded in producing ethanol through SSF; however, the extent to which inhibitors by-produced from lignocellulose hydrolysis affect the growth and ethanol productivity of the two strains remains to be investigated. In this study, to better understand the inhibitor tolerance capacity of the two strains, spot assay, growth experiment, real-time quantitative PCR (RT-qPCR) analysis and multiple sequence alignment analysis were carried out. When P. kudriavzevii NBRC1279 and NBRC1664, as well as Saccharomyces cerevisiae BY4742 as a control, were cultured on SCD plates containing 17% ethanol, 42 mM furfural, 56 mM 5-hydroxymethylfurfural (HMF) or 10 mM vanillin, only P. kudriavzevii NBRC1664 was able to grow under all conditions. Moreover, the inhibitor tolerance capacity of P. kudriavzevii NBRC1664 was greater than those of other strains using SCD medium containing the same concentrations of various inhibitors. When an RT-qPCR analysis of seven gene sequences from aldehyde dehydrogenase and the aldehyde dehydrogenase family protein (ADHF) was performed using P. kudriavzevii NBRC1664 cultivated in the presence of 56 mM HMF, ADHF1 and ADHF2 were up-regulated in the early logarithmic growth phase. Moreover, a multiple sequence alignment of the amino acid sequences of ADHF1, ADHF2 and the known ADH suggested that ADHF1 and ADHF2 may catalyze the reversible NAD+-dependent oxidation of HMF. Our data may be useful for future studies on the metabolic engineering of more useful strains for ethanol production from lignocellulose. [ABSTRACT FROM AUTHOR]

In this study, biochemical analyses of honey produced in Hizan district of Bitlis province which is one of the important honey centers of Turkey, were performed. In the research, 7 honey samples collected from villagers dealing with beekeeping in different regions of Hizan were studied. Hydroxymethylfurfural (HMF), antioxidant activities, sugar, flavonoid and total phenolic levels were measured with the HPLC device. As a result, the flavonoid, sugar and total phenolic levels of 1, 4, 5 and 7 honeys were similar to the properties of natural honeys. The HMF values of all honey samples were found to be in accordance with the value determined in the Turkish Food Codex Honey Communiqué. It was determined that the honeys used in our study have scavenging properties on DPPH and ABTS radicals. In addition, the maltose value of the 3 and 5 honey samples was found to be slightly higher than that of the other honey samples. Since maltose is formed as a result of the hydrolysis of starch, it cannot be found naturally in plant juices. Honey samples with high maltose content are considered to be produced under unnatural conditions. The antioxidant and chemical properties of Bitlis-Hizan honey make them high value-added quality products. As a result, it was seen that the results comply with EU standards and the Turkish Food Codex Honey Communiqué. [ABSTRACT FROM AUTHOR]

Sago pith waste (SPW), a biomass processing waste, still contains starch after the starch extraction process and consequently can add value to the starch industry's byproducts. In this study, SPW was placed in a biphasic tetrahydrofuran (THF) system. THF was used as the primary solvent during one-pot production for the in situ extraction of hydroxymethylfurfural (HMF). We aimed to obtain a higher yield of HMF from SPW using a THF–water biphasic system and to compare the life-cycle assessment (LCA) of SPW-based HMF production in the THF–water and dimethyl sulfoxide (DMSO)–water systems. Increased HMF production was seen at 160 ℃ for 45 min with aluminum sulfate as a catalyst and the addition of sodium chloride. We obtained 32.6% HMF from SPW using a THF–water biphasic system. Additionally, approximately 30% of HMF can be found in the crude extraction solutions. We then analyzed the LCA to consider the development of HMF in the industry by comparing the HMF system from our previous research on DMSO–water. The THF–water system had less environmental impact than the DMSO–water system owing to its higher HMF concentration in the crude extract. These findings can further help to develop environmentally friendly HMF production processes. [ABSTRACT FROM AUTHOR]

The selective oxidation of 5‐(Hydroxymethyl)furfural (HMF) to 2,5‐Furandicarboxylic acid (FDCA) is highly attractive for the production of renewable monomers as substitute for fossil‐based monomers. To achieve a sustainable synthesis, we report on advances for a base‐free approach, reducing waste from the process, using air as oxidant and heterogeneous catalysts. Various Carbon‐based supports, which can be bio‐sourced and cost‐efficient, for Pt particles were investigated as they allow for an easy reuse and at the end‐of‐life Pt can be recycled to enable a closed cycle. Commercially available supports with varying properties, which might replace the base, were studied with Pt particles of similar size and loading. Significant differences in the catalytic activity were observed, which were correlated with the O‐functionalities and graphitization degree of the supports derived from Raman spectroscopy, temperature‐programmed desorption, and X‐ray photoelectron spectroscopy. An activated carbon (Norit ROX) rich in quinone/pyrone‐type groups and a carbon black‐based catalyst with graphene‐layers pushed the efficiency with enhanced FDCA‐yields enabling the complete substitution of the homogeneous base. This allows to circumvent the base in this process which together with high selectivity, air as oxidant, a reusable catalyst, and the use of bio‐based feedstock contributes to the sustainability of the production of renewable monomers. [ABSTRACT FROM AUTHOR]

Selective oxidation of 5-hydroxymethylfurfural (HMF) to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) is a promising yet challenging task, producing significant chemical feedstocks. The development of nonprecious and efficient catalytic system for biomass-derived HMF is of great importance for HMFCA production. Herein, a magnetic Ag/GO/Fe3O4/γ-Fe2O3 nanocomposite with p–n heterojunctions was fabricated using a simple refluxing method followed by an autoclave step at 120 °C. The Ag/GO/Fe3O4/γ-Fe2O3 nanocomposite is employed as a photocatalyst for the selective oxidation of HMF toward HMFCA with high conversion (99%) and selectivity (98%). The products were separated and determined using high-performance liquid chromatography-ultraviolet. The structural integrity of the synthesized photocatalyst was corroborated by Fourier-transform infrared, field emission scanning electron microscopy, energy dispersive X-ray, transmission electron microscopy, vibrating sample magnetometer, dynamic light scattering, X-ray diffraction, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, photoluminescence, and BET-BJH. Various parameters were checked, such as temperature, amount of catalyst, time, base, light sources, light intensity, recyclability, and the efficiency of the photocatalyst. In result, the highest photocatalytic efficiency (98%) was obtained using 0.03 mol % of Ag/GO/Fe3O4/γ-Fe2O3 nanocomposite under green light emitting diode light irradiation (12 W) for 1.5 h. Therefore, such a protocol provides a route to enhance the photocatalytic properties and performance of semiconductor materials for synthesizing biomass-derived value-added chemicals under environmentally friendly conditions. [ABSTRACT FROM AUTHOR]

Abundantly available biomass‐based platform chemicals, including 5‐hydroxymethylfurfural (HMF), are essential stepping stones in steering the chemical industry away from fossil fuels. The efficient catalytic oxidation of HMF to its diacid derivative, 2,5‐furandicarboxylic acid (FDCA), is a promising research area with potential applications in the polymer industry. Currently, the most encouraging approaches are based on solid‐state catalysts and are often conducted in basic aqueous media, conditions where HMF oxidation competes with its decomposition. Efficient molecular catalysts are practically unknown for this reaction. In this study, we report on the synthesis and electrocatalysis of surface‐bound molecular ruthenium complexes for the transformation of HMF to FDCA under acidic conditions. Catalyst immobilisation on mesoporous indium tin oxide electrodes is achieved through the incorporation of phosphonic acid anchoring groups. Screening experiments with HMF and further reaction intermediates revealed the catalytic route and bottlenecks in the catalytic synthesis of FDCA. Utilising these immobilised electrocatalysts, FDCA yields of up to 85 % and faradaic efficiencies of 91 % were achieved, without any indication of substrate decomposition. Surface analysis by X‐ray photoelectron spectroscopy (XPS) post‐electrocatalysis unveiled the desorption of the catalyst from the electrode surface as a limiting factor in terms of catalytic performance. [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 <1 log CFU/g after 24 months of storage) compared to unprocessed honey and honey thermally treated under mild conditions (55 °C/15 min). The physicochemical characteristics of the quality of HPP-treated honey and raw unprocessed honey did change after long-term storage (24 months) but remained within regulatory standards. In conclusion, HPP emerged as a more suitable and safe preservation method for Apis mellifera honey, with a minimal risk of a loss of antioxidant activity compared to traditional industrial honey pasteurization. [ABSTRACT FROM AUTHOR]

Hydrogen bonding effect exists widely in various chemical and biochemical systems, primarily stabilizing the molecular structure as a positive factor. However, the presence of intermolecular hydrogen bonds among biomass molecules results in a formidable challenge for the efficient utilization of biomass resources. Here in, a novel strategy of "hydrogen bonds reconstruction" was developed by a series of ternary deep eutectic solvent (DESs) as molecular scissors, which disrupting the initial intermolecular hydrogen bonds and reconstructing the new ones to increase the reactivity of the biomass‐based compound. The DESs played a crucial role in enhancing the reactivity of 5‐hydroxymethylfurfural (HMF) and promoting its oxidation through reconstructing the hydrogen bonds interactions. Furthermore, DESs was also found to activate the Anderson‐type catalyst Na5IMo6O24 (IMo6) through an electron‐transfer mechanism, which facilitated the generation of oxygen vacancies and significantly enhances its ability to activate molecular oxygen. With this novel catalytic system, oxidation of HMF exhibited remarkable efficiency as HMF was almost entirely converted into FFCA with an impressive yield of 98 % under the optimized conditions. This finding offers novel insights into the utilization of biomass resources and endows the solvent with new functions in the chemical reaction. [ABSTRACT FROM AUTHOR]

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Usually costs of bio‐based products are compared to those of their fossil counterparts, most often made from crude oil. This paper adds new insights into this kind of comparison and provides approaches as to how future innovations in biorefineries and bio‐based chemicals can be compared to commercial fossil alternatives. The shift to alternative carbon sources will lead to higher costs in the short term. However, expected changes in the crude oil market and regulatory effects will cause rising costs of fossil chemicals in the near future. This work also provides strategies for implementing increased prices. [ABSTRACT FROM AUTHOR]

Garlic (Allium sativum L.), a member of the Alliaceae family, has been widely used in cuisine and traditional medicine since ancient times. Black garlic is produced by fermentation of fresh garlic under controlled conditions for a certain period at high temperature (60-90°C) and high humidity (70-90%). According to the Turkish Statistical Institute (TURKSTAT) data, Kastamonu and Gaziantep garlic varieties are the most cultivated garlic varieties in our country. Changes in protein, sugar content, antioxidant capacity (DPPH and ABTS methods), total phenolic content, 5-hydroxymethylfurfural (HMF) content, and organosulfur compound profiles were investigated in samples taken from Kastamonu and Gaziantep fresh garlic at 7, 14, 21, and 28 days of black garlic production under 65°C temperature and 70% humidity conditions. With these analyses, the differences between black garlic and fresh garlic and the changes in black garlic during the production process were revealed in detail. It was determined that the amount of total phenolic content and antioxidant capacities increased in the black garlic production processes of both regions compared to fresh garlic. While sucrose was fresh garlic's dominant sugar, fructose was black garlic's dominant sugar. Among the organosulfur compounds, allicin was dominant in fresh garlic and SAC in black garlic. It was determined that SAC was formed after the enzymatic conversion of ɣ-glutamyl-S-alk(en)yl-L-cysteine and ɣ-glutamyl and the temperature and fermentation time used in black garlic production increased the formation of SAC. The protein content ranging between 5.8%-7.3% in fresh garlic was 13.1-14.2% in black garlic. Fresh and black garlic from the Gaziantep region was determined to have higher total phenolic content, antioxidant capacity, and organosulfur compound contents. [ABSTRACT FROM AUTHOR]

The valorization of C5 sugars (xylose) from hemicellulose of agro-industrial residues to xylitol, as one of the multi-products biorefinery approach, mandates the pretreatment of biomass which releases fermentable sugars along with the generation of biological inhibitors affecting xylitol fermentation. This study was therefore evaluated to understand the inhibitory kinetics of furfural, 5-hydroxymethylfurfural and acetic acid on xylitol fermentation. Xylitol fermentation was established using Pichia stipitis NCIM 3497 with xylose as a pure substrate optimized for xylitol yield and productivity of 0.48 g/g of xylose and 0.13 g/L/h, respectively. The functional relationship of yeast specific growth rate and limiting substrate (xylose) was expressed by Monod-type kinetics. The inhibition kinetics results indicated that the effect of inhibitors on xylitol fermentation was furfural > acetic acid > HMF. Furfural (500 mg/L) and acetic acid (1000 mg/L) reduced xylitol yield by 59% and 44%, respectively, with least reduction of 9.89% exhibited by HMF. The synergistic effect of 500 mg/L furfural, 500 mg/L HMF and 1000 mg/L acetic acid showed the highest reduction in xylitol yield of 67.6% as compared to the control. Kinetic studies predicted that the maximum concentration of furfural, HMF and acetic acid which inhibited P. stipitis growth was 884 mg/L, 3258 mg/L and 2922 mg/L, respectively, whereas xylitol production was completely inhibited at 1069 mg/L furfural, 3498 mg/L HMF and 3714 mg/L acetic acid. Furfural and acetic acid were found to be a competitive inhibitor, while uncompetitive inhibition was observed with HMF indicating negligible effect on xylitol fermentation. [ABSTRACT FROM AUTHOR]

Over the past century, chemicals and energy have increasingly been derived from non-renewable resources. The growing demand for essential chemicals and shrinking inventory make reliable, sustainable sources essential. Carbohydrates offer by far the greatest carbon supply. Furan compounds, a particular family of dehydration products, are believed to offer high chemical potential. Here, we analyze 5-HMF (5, hydroxymethylfurfural) and some of its derivatives in particular, a furan-type platform chemical. To analyze the therapeutic potential of HMF and its derivatives, this study utilized cutting-edge technologies such as computer-aided drug design, virtual screening, molecular docking, and molecular dynamic simulation. We conducted 189 docking simulations and examined some of the most promising dock poses using the molecular dynamic simulator. As for the receptors for our compounds, the leading candidates are human acetylcholinesterase, beta-lactamases, P. aeruginosa LasR, and S. aureus tyrosyl-tRNA synthetases. Out of all derivatives considered in this study, 2,5-furandicarboxylic acid (FCA) performed best. [ABSTRACT FROM AUTHOR]

Honey is a natural nice substance produced by bees, physicochemical properties of bee’s honey to help beekeepers procreation high-quality bee’s honey. A total number of 20 Libyan honey samples were collected from different areas in Libya through 2016 – 2017, from east, west, southeast and southwest regions. These samples were analyzed for six physiochemical parameters of honey control i.e.,pH, moisture, ash content, insoluble mater porline control and HMF . The aim of this study is to give view about the quality of Libyan honey, which is suffering from paucity of characterization data. The results of physiochemical characteristic of Libyan honey samples, the pH of Libyan honey samples range from 3.25 to 5.00, with a mean of 4.101 . These values are comparable to the pH values of U.S. honey (range 3.4 to 6.1), the moisture content of honey samples range from 7.76 to 15 % which is found within the limits prescribed by Codex Alimentarious Commission(1969), i.e. not more than 21%. The mean of ash content of honey samples were 0.313 %, with the range of 0.1-0.95 %. These values are comparable to the values of U.S. honey which has mean of o.169%, with a range from 0.020 to 1.028%. The Hydroxymethylfurfural (HMF) content of Libyan honey samples are found within the limits prescribed by the Codex Alimentarious Commission(1969), Insoluble matter content of Libyan honey samples range from 0.005 to 0.149 % . with mean of 0.06175 % . The range of proline content of Libyan honey samples arek from 350 to 1079.4 mg / kg, with mean of 626.2 mg / kg. [ABSTRACT FROM AUTHOR]

The utilization and development of biomass resources is an efficient solution to mitigate the fossil energy crisis. Based on the advantages of mild reaction conditions, rapid reaction, and high conversion, the synthesis of 2,5-furandicarboxylic acid (FDCA) by the electrocatalytic oxidation of 5-hydroxymethylfurfural (HMFOR) has attracted considerable attention. This review will summarize the recent advances of HMFOR to FDCA, including the reaction pathway and mechanism, as well as the catalytic performance of various heterogeneous electrocatalysts. The challenges and prospects for HMFOR are also focused on. Finally, it is expected that this work may provide guidance for the design of high-efficiency electrocatalysts and thereby accelerate the industrialization process of biomass utilization. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The blue honeysuckle berry is a fruit known as a rich source of many bioactive substances with proven health-promoting effects. Due to its sour taste with a noticeable hint of bitterness, fruits of this plant are rarely consumed and the consumer prefers the processed form. The purpose of this study was to evaluate the effect of the cooking method on the biological quality of honeysuckle berry confiture. The selected recipe was used to make confiture in a vacuum evaporator using lowered pressure and in a thermomix vessel under atmospheric pressure. Then, the content of the chosen compounds and antioxidant activity of the two types of confitures were compared. The confitures were analyzed right after production and through 180 days of refrigerated storage. The pH, TA and TSS parameters remained unchanged regardless of the production process and storage time. Ascorbic acid, polyphenol and anthocyanin concentrations were greater in the confiture from vacuum cooking. Also, the same confiture showed a lower rate of degradation of bioactive substances during storage. The antioxidant activity of the two types of confiture was significantly different shortly after production, but equal at the end of 180-day storage. HMF content was four times higher in confitures cooked under atmospheric pressure than under vacuum. The confiture made from the honeysuckle berry was very rich in bioactive compounds, especially polyphenols. Vacuum cooking proved to be the best method for confiture production as a result of lower temperatures used and less aeration of the mass. [ABSTRACT FROM AUTHOR]

BACKGROUND: Anthocyanins are responsible for both attractive colour of pomegranate juice (PJ) and its health‐promoting effects against cancer and coronary heart disease. However, 5‐hydroxymethylfurfural (HMF) at some concentrations causes anthocyanin degradation. The present study aimed to reduce the degradation of PJ anthocyanins as a result of HMF at various concentrations (0–20 mg L−1) through phenolic acid [PA; ferulic (FA), gallic (GA) and caffeic acids (CA)] copigmentation during storage at 20 °C. RESULTS: A strong correlation (r = 0.872) was found between anthocyanin degradation rate and HMF concentration in PJ without PA addition. An increase in HMF concentration during storage caused faster (< 32%) anthocyanin degradation. However, PA addition reduced (< 60 times) the HMF formation rate. The lowest HMF formation rates (0.07–0.28 day−1) were determined in PJ with added GA. Although GA caused an important increase in content of cyanidin‐3‐glucoside (16–42%), which is major PJ anthocyanin, against HMF at all concentrations, CA (15%) and FA (28%) increased cyanidin‐3‐glucoside content against 10 mg of HMF L−1. FA maintained its protection effect against the highest HMF concentration (20 mg of HMF L−1), but CA lost its protection effect. Generally, FA increased stabilities of hyperchromic effect (HE) (9.6–27.7%) and colour density (CD) (57.1–74.3%) at all HMF concentrations, although CA increased HE stability (19.8–37.7%) in the presence of 10 and 20 mg of HMF L−1. Interactions of 'all individual anthocyanins‐FA' and 'delphinidin‐based anthocyanins‐GA/CA' resulted in copigmentation. CONCLUSION: FA addition was recommended to increase CD and HE for PJ containing HMF between 3.1–5.6 mg L−1, whereas the addition of GA was recommended to increase anthocyanin stability for PJ containing 12.0 mg of HMF L−1. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Summary: Cacao mucilage exudate (CME) is a highly nutritious by‐product of cacao fruit processing containing up to 15 wt% simple sugars and organic acids. We investigate the CME dehydration process to produce cacao syrup (CS) under varying temperatures (60 °C and 70 °C) and pH (4.0 and 5.0) using a 22‐factorial design with a central point (65 °C, pH 4.5). Neither temperature nor pH significantly (P < 0.05) impacts CS chemical composition. Average concentrations of fructose, glucose, and sucrose in the syrups reached 27.79, 25.56, and 12.46 wt%, respectively. Organic acids—citric, malic, lactic, tartaric, and fumaric—represent 5.12, 3.01, 0.20, 0.16, and 0.002 wt%, respectively. Although the heating treatment results in the formation of 5‐(hydroxymethyl)furfural (HMF) (12.8–13.7 mg L−1), its concentration remains below the limits of the regulatory standard. These findings have significant implications for using CME as a sustainable and nutritious source of ingredients for the food industry. [ABSTRACT FROM AUTHOR]

Owing to the abundance of availability, low cost, and environmental‐friendliness, biomass waste could serve as a prospective renewable source for value‐added chemicals. Nevertheless, biomass conversion into chemicals is quite challenging due to the heterogeneous nature of biomass waste. Biomass‐derived chemicals are appealing sustainable solutions that can reduce the dependency on existing petroleum‐based production. Metal‐organic frameworks (MOFs)‐based catalysts and their composite materials have attracted considerable amounts of interest in biomass conversion applications recently because of their interesting physical and chemical characteristics. Due to their tunability, the catalytic activity and selectivity of MOF‐based catalyst/composite materials can be tailored by functionalizing them with a variety of functional groups to enhance biomass conversion efficiency. This review focuses on the catalytic transformation of lignocellulosic biomass into value‐added chemicals by employing MOF‐based catalyst/composite materials. The main focus is given to the production of the platform chemicals HMF and Furfural from the corresponding (hemi)cellulosic biomass, due to their versatility as intermediates for the production of various biobased chemicals and fuels. The effects of different experimental parameters on the conversion of biomass by MOF‐based catalysts are also included. Finally, current challenges and perspectives of biomass conversion into chemicals by MOF‐based catalysts are highlighted. [ABSTRACT FROM AUTHOR]

Following years of its exploitation from only wild colonies, the stingless bee (Meliponula bocandei Spinola, 1853) was recently domesticated in Uganda. Products currently harvested by the beekeepers are honey and propolis. Studies from other countries have shown that stingless bees produce honey that is distinct in physicochemical properties. Therefore, in an effort to lay a foundation for the development of quality standards for stingless bee honey in Uganda, we collected M. bocandei honey from the Western Highlands and Lake Victoria Crescent agroecological zones. A selected set of physicochemical properties (moisture content, viscosity, water activity, electrical conductivity and HMF) of the honey were determined. Results reveal the following means of the physicochemical properties: moisture content (26.45 ± 3.9%), viscosity (38.32 ± 2.25 Pa.s), water activity (0.71 ± 0.04%), electrical conductivity (0.229 ± 86.91 mS/cm), pH (4.15 ± 0.68), and HMF (5.42 ± 4.78 mg kg−1), The low mean HMF reveals that stingless bee honey from these two agroecological zones is of good quality. Overall, the mean values of the physicochemical parameters measured are within the figures in the East African Community standards for stingless bee honey. We recommend investigations to establish the diversity of forage plant resources used by the stingless bee M. bocandei in order to boost meliponiculture. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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]

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]

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]

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]

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]