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The photocatalytic oxidation of biomass-derived building blocks such as 5-hydroxymethylfurfural (HMF) is a promising reaction for obtaining valuable chemicals and the efficient long-term storage of solar radiation. In this work, we developed innovative TiO 2 -based materials capable of base-free HMF photo-oxidation in water using simulated solar irradiation. The materials were prepared by combining microemulsion and spray-freeze drying (SFD), resulting in highly porous systems with a large surface area. The effect of titania/silica composition and the presence of gold-copper alloy nanoparticles on the properties of materials as well as photocatalytic performance were evaluated. Among the lab-synthesized photocatalysts, Ti 15 Si 85 SFD and Au 3 Cu 1 /Ti 15 Si 85 SFD achieved the higher conversions, while the best selectivity was observed for Au 3 Cu 1 /Ti 15 Si 85 SFD. The tests with radical scavengers for both TiO 2 -m and Au 3 Cu 1 /Ti 15 Si 85 SFD suggested that primary species responsible for the selective photo-oxidation of HMF are photo-generated electrons and/or superoxide radicals.

False indigo ( Amorpha fruticosa L., A. fruticosa ) is the preferred tree indigenous for windbreak and sand control in Northwest China, while information on nutritional and bioactive characteristics of its honey is rare. Herein, 12 honey of Amorpha fruticosa L. (AFH) were sampled in Northwest China and the nutritional composition was determined. Sixteen mineral element and ten dominant polyphenols content were identified and quantified by ICP-MS (Inductively coupled plasma mass spectrometry) and HPLC-QTOF-MS (High performance liquid chromatography-Quadrupole time-of-flight mass spectrometry), respectively. Moreover, AFH demonstrated high levels of DPPH (1,1-Diphenyl-2-picrylhydrazyl) radical scavenging activity (IC50 100.41 ± 15.35 mg/mL), ferric reducing antioxidant power (2.04 ± 0.29 µmol FeSO 4 ·7H 2 O/g), and ferrous ion-chelating activity (82.56 ± 16.01 mg Na 2 EDTA/kg), which were significantly associated with total phenolic contents (270.07 ± 27.15 mg GA/kg) and ascorbic acid contents (213.69 ± 27.87 mg/kg). The cell model verified that AFH exhibited dose-dependent preventive effects on pBR322 plasmid DNA and mouse lymphocyte DNA damage in response to oxidative stress. Taken together, our findings provide evidence for the future application of AFH as a potential antioxidant dietary in food industry.

Background: Sterilization of milk is aimed at killing the microorganisms present. There are three main sterilization methods commonly used in milk processing: high temperature and short time (HTST) pasteurization, ultrahigh pasteurization (UP), and ultrahigh temperature (UHT) sterilization. The Maillard reaction is of special interest in studying the effect of heat treatment on milk quality. Furfural compounds are one of the typical intermediates of the Maillard reaction, which have safety risks related to mutagenic and genotoxic effects. The furfural compounds content is directly related to the heat treatment intensity., Results: The furfural compounds content was measured using high-performance liquid chromatography with ultraviolet detection in 12 min. Then, 13 levels of heat treatment intensity (combinations of temperature and time) and three levels of homogenization pressure were selected to study the change of the furfural compounds content after different processing technologies in a pilot plant. The results show a higher temperature treatment can stimulate more Maillard reaction intermediates, such as hydroxymethylfurfural and furfural. A temperature regression evaluation model and content prediction models of hydroxymethylfurfural and furfural were developed to quantify the relationship between the furfural content and heat treatment with the data from the pilot plant., Conclusion: Based on the temperature evaluation model, the heating temperature of three milk products was evaluated. The homogenization pressures had little effect on the furfural content in liquid milk. The emergence of the furyl methyl ketone and methylfurfural can be detected after overprocessing of the liquid milk. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

In this work, 5-(formyloxymethyl)furfural (FMF) has been produced from biomass-derived hexose sugars within a biphasic reaction mixture consisting of aqueous formic acid (85%), a strong Brønsted acid catalyst, and 1,2-dichloroethane as an organic extractant. Using a combination of aqueous hydrobromic acid and formic acid, under optimized condition (80 °C, 8 h, 10 wt% substrate loading), 68% isolated yield of FMF was obtained from fructose. FMF has been demonstrated as a renewable chemical building block for the synthesis of renewable chemicals of commercial significance such as 5-methylfurfural, 2,5-diformylfuran, and 2,5-furandicarboxylic acid in good to excellent isolated yields., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Nb(0.05 moles%)-zeolites prepared via a post synthesis methodology (BEA, Y, ZSM-5), or a direct sol-gel method (Silicalite-1) were investigated in the hydroxymethylfurfural (HMF) oxidation by both molecular oxygen, in aqueous phase, and organic peroxides, in acetonitrile. The catalysts prepared through the post synthesis methodology (i.e., Nb-Y5, Nb-ZSM25, Nb-Y30, Nb-BEA12, and Nb-BEA18) displayed a mono-modal mesoporosity and contain residual framework Al-acid sites, extra framework isolated Nb(V)O-H and Nb 2 O 5 pore-encapsulated clusters, while Nb-Sil-1, prepared through a direct synthesis procedure, displayed a bimodal micro-mesoporosity and contains only -Nb=O species. These modified zeolites behave as efficient catalysts in both HMF/glucose wet oxidation to succinic acid (SA) and HMF oxidation with organic peroxides to the 2,5-furandicarboxylic acid (FDCA). The catalytic behavior of these catalysts, in terms of conversion and especially the selectivity, mainly depended on the base/acid sites ratio. Thus, the HMF/glucose wet oxidation occurred with a total conversion and a selectivity to SA of 37.7% (from HMF) or 69.1% (from glucose) on the Nb-Y5 catalyst, i.e., the one with the lowest base/acid sites ratio. On the contrary, the catalysts with the highest base/acid sites ratio, i.e., Nb-ZSM25 and Nb-Sil-1, afforded a high catalytic efficiency in HMF oxidation with organic peroxides, in which FDCA was produced with selectivities of 61.3-63.8% for an HMF conversion of 96.7-99.0%.

5-Hydroxymethylfurfural (HMF) is a promising bio-derived platform chemical with a broad scope of application, for example, in the production of solvents, fuels, polymers, or adhesives. The wood and foundry industries are among the largest adhesive users and currently both rely to a large extent on the use of fossil-based binders, such as by using formaldehyde as a crosslinker in many commercial adhesive systems. The industry is thus looking for suitable alternatives to replace fossil-based chemicals. HMF and its derivatives are considered to be key renewable reactants in adhesive systems. The core of this Review is the critical evaluation of the potential of HMF and its derivatives in adhesive systems. The technological performance was assessed in the fields of wood-based materials, sand casting and composites. As an overall conclusion, HMF and its derivatives have a high application potential in alternative adhesives. Clearly, further research is needed to improve the performance and produce economically competitive adhesives., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

Aminomethylhydroxymethylfuran derivatives are well known compounds which are used in the pharmaceutical industry. Reductive amination of 5-hydroxymethylfurfural (HMF) derived from available non-edible lignocellulosic biomass is an attractive method for the synthesis of this class of compounds. In the present study, the synthesis of N-substituted 5-(hydroxymethyl)-2-furfuryl amines and 5-(acetoxymethyl)-2-furfuryl amines was performed by two-step process, which includes the condensation of furanic aldehydes (HMF and 5-acetoxymethylfurfural) with primary amines in methanol on the first step and the reduction of obtained imines with hydrogen in a flow reactor over CuAlO x catalyst derived from layered double hydroxide on the second step. This process does not require isolation and purification of intermediate imines and can be used to synthesize a number of aminomethylhydroxymethylfurans in good to excellent yield.

Three different metal oxides (basic MgO, basic-acidic Al 2 O 3 and acidic-basic Nb 2 O 5 ) characterized by comparable surface areas (MgO-130 m 2 /g; Al 2 O 3 -172 m 2 /g and Nb 2 O 5 -123 m 2 /g) and pore systems (domination of mesopores with narrow pore size distribution) were modified with tris(2-aminoethyl)amine (TAEA) via two methods: (i) direct anchoring of amine on metal oxide and (ii) anchoring of amine on metal oxide functionalized with (3-chloropropyl)trimethoxysilane. The obtained hybrid materials were characterized in terms of effectiveness of modifier anchoring (elemental analysis), their structural/textural properties (nitrogen adsorption/desorption, XRD), acidity/basicity of support (2-propanol dehydration and dehydrogenation, dehydration and cyclization of 2,5-hexanedione), states of modifier deposited on supports (XPS, FTIR, UV-VIS) and the strength of interaction between the modifier and the support (TG/DTG). It was evidenced that acidic-basic properties of metal oxides as well as the procedure of modification with TAEA determined the ways of amine anchoring and the strength of its interaction with the support. The obtained hybrid materials were tested in Knoevenagel condensation between furfural and malononitrile. The catalysts based on MgO showed superior activity in this reaction. It was correlated with the way of TAEA anchoring on basic MgO and the strength of modifier anchoring on the support. To the best of our knowledge tris(2-aminoethyl)amine has not been used as a modifier of solid supports for enhancement of the catalyst activity in Knoevenagel condensation.

Catalytic strategies were developed to synthesize and release chemicals for applications in fine chemicals, such as drugs and polymers, from a biomass-derived chemical, 5-hydroxymethyl furfural (HMF). The combination of the diene and aldehyde functionalities in HMF enabled catalytic production of acetalized HMF derivatives with diol or epoxy reactants to allow reversible synthesis of norcantharimide derivatives upon Diels-Alder reaction with maleimides. Reverse-conversion of the acetal group to an aldehyde yielded mismatches of the molecular orbitals in norcantharimides to trigger retro Diels-Alder reaction at ambient temperatures and released reactants from the coupled molecules under acidic conditions. These strategies provide for the facile synthesis and controlled release of high-value chemicals., (© 2020 Wiley-VCH GmbH.)

Furfural has been produced in 53% isolated yield from d-xylose within an aqueous HCl-1,2-dichloroethane biphasic reaction mixture using benzyltributylammonium chloride (BTBAC) as a phase transfer catalyst. The use of BTBAC noticeably improved the yield of furfural compared to that in the control reaction. The reaction was optimized on the reaction temperature, duration, concentration of HCl, and the loading of BTBAC. Furfural and 5-(chloromethyl)furfural (CMF) have also been coproduced from a mixture of pentose and hexose sugars. Under optimized conditions (100 °C, 3 h, 20.2% HCl, 10 wt% BTBAC), CMF and furfural were isolated in 17% and 53% yield, respectively, from a mixture of glucose and xylose. In addition, levulinic acid was isolated from the aqueous layer in 31% yield., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Controlling the formation of nanosized branched nanoparticles with high uniformity is one of the major challenges in synthesizing nanocatalysts with improved activity and stability. Using a cubic-core hexagonal-branch mechanism to form highly monodisperse branched nanoparticles, we vary the length of the nickel branches. Lengthening the nickel branches, with their high coverage of active facets, is shown to improve activity for electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF), as an example for biomass conversion., (© 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

Background: The aims of this study are to (i) evaluate the effects of color enhancers, caramel (C) and molasses (M), on acrylamide and 5-hydroxylmethylfurfural (HMF) formation in non-centrifugal cane sugar (NCS) and to (ii) perform nine-point hedonic scale and evaluation of sensory attributes, encompassing the appearance, flavor, texture and aftertaste, by 71 consumers on NCS, NCS&#95;C, and NCS products made with a blend of molasses and sugar (NCS&#95;MS) and steam processing (NCS&#95;S)., Results: With the addition of molasses and caramel at the maximum allowable level of 5 g kg -1 in sugarcane juice, significantly greater acrylamide or HMF did not accumulate in NCS&#95;C and NCS&#95;M during the thermal manufacturing process, while color values of NCS&#95;C significantly changed (P < 0.05). The increases in acrylamide and HMF contents were influenced by pH because they were produced by the Maillard reaction. Hedonic responses showed that NCS&#95;MS was rated with the highest score for overall acceptance, whereas NCS&#95;S, with the lowest content of acrylamide, exhibited the lowest score for every attribute. In addition, the appearance acceptance score of NCS&#95;C was significantly higher than that of NCS (P < 0.05). Significant differences were also found between NCS and NCS&#95;C in the frequency of 9 of 16 items with which consumers selected to characterize the appearance in a check-all-that-apply questionnaire (P < 0.05)., Conclusions: The association between hedonic evaluations and sensory profiles in visual attributes of NCS&#95;C indicated that caramel could be a promising addition in Maillard reaction-mitigated NCS products to improve consumer preferences through color strengthening without safety concerns. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

A series of defect pyrochlores of the composition (H3O)1+pSb1+pTe1-pO6 have been prepared by ion exchange from K-containing pyrochlores K1+pSb1+pTe1-pO6 in sulfuric acid at 280 °C for 24 h. The structural characterization of the hydronium-containing pyrochlores, including the location of the H3O+ units within the three-dimensional framework, was possible from neutron powder diffraction data in undeuterated samples. The crystal structure for all the compounds is defined in the Fd3[combining macron]m space group, and consists of a covalent framework of SbVO6 and TeVIO6 octahedra distributed at random and connected by their vertices with (Sb,Te)-O1-(Sb,Te) angles close to 136°, conforming to large cages where the hydronium species are located off-center. The absence of K+ ions in the ion-exchanged pyrochlores was confirmed by inductively coupled plasma optical emission spectroscopy and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The shape and size of the hydronium units evolve along with the series, becoming more compact as the framework covalence and Lewis-basicity decrease upon Sb enrichment of the structure (for greater p values). The amount and lability of the H3O+ species also increase throughout the series, as wanted: a straightforward correlation of the catalytic activity in the fructose dehydration reaction to 5-hydroxymethylfurfural has been observed, reaching conversion rates up to 88.5% of concentrated fructose solution for the p = 0.25 catalyst. Moreover, a pseudo-first-order kinetic mechanism was simulated, and the kinetic constants obtained from diluted and concentrated enhanced reaction systems were determined and compared.

The production of furfural from renewable sources, such as lignocellulosic biomass, has gained great interest within the concept of biorefineries. In lignocellulosic materials, xylose is the most abundant pentose, which forms the hemicellulosic part. One of the key steps in the production of furfural from biomass is the dehydration reaction of the pentoses. The objective of this work was to assess the conditions under which the concentration of furfural is maximized from a synthetic, monophasic, and homogeneous xylose medium. The experiments were carried out in a microwave reactor. FeCl 3 in different proportions and sulfuric acid were used as catalysts. A two-level, three-factor experimental design was developed for this purpose. The results were further analyzed through a second experimental design and optimization was performed by response surface methodology. The best operational conditions for the highest furfural yield (57%) turned out to be 210 °C, 0.5 min, and 0.05 M FeCl 3 .

Transformation of renewable biomass into value-added chemicals and biofuels has evolved to be a vital field of research in recent years. Accurate estimation of reducing sugars post pretreatment of lignocellulosic biomass has been very inconsistent. For a few decades, 3,5-dinitrosalicylic acid (DNS) assay has been widely employed for the estimation of reducing sugars derived from pretreatment of lignocellulosic biomass. This assay tests for the presence of free carbonyl group (C=O), the so-called reducing sugars. This involves the oxidation of the aldehyde functional group present to the corresponding acid while DNS is simultaneously reduced to 3-amino-5-nitrosalicylic acid under alkaline conditions. However, the presence of other active carbonyl groups can potentially also react with DNS leading to incorrect yields of reducing sugars. Therefore, a detailed study has been carried out to evaluate the influence of active carbonyl compounds like furfural and 5-hydroxymethylfurfural (5-HMF) in the overall estimation of reducing sugars (glucose, xylose and arabinose) by DNS assay. In addition to this, reducing sugars estimation in the presence of furans were also investigated, it reveals that reducing sugars estimation was found to be 68% higher than actual sugars. Therefore, current findings strongly indicate that the employment of DNS assay for quantifying the reducing sugars in the presence of furans is not appropriate., (Copyright © 2020. Published by Elsevier B.V.)

This study aims to investigate in depth the mechanism of acrylamide formation in coffee during roasting. For this purpose, a comprehensive kinetic model including the elementary steps for acrylamide formation was proposed. The changes in sucrose, reducing sugars, free amino acids, asparagine, acrylamide, 3-deoxyglucosone, methylglyoxal, glyoxal, and 5-hydroxymethylfurfural were monitored in coffee during roasting at 200, 220 and 240 °C. Dominant pathways of complex reactions leading to acrylamide were unravelled by means of multiresponse kinetic modelling approach. The results of the model indicated that sucrose degrades into glucose and a reactive fructofuranosyl cation. Interestingly, glucose takes part mostly in the formation of intermediates, glyoxal and especially 3-deoxyglucosone rather than acrylamide formation. On the other hand, fructofuranosyl cation contributed mostly to the formation of 5-hydroxymethylfurfural which was found to be the most important intermediate precursor of acrylamide formed in coffee during roasting., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Furans represent one of the most important classes of intermediates in the conversion of non-edible lignocellulosic biomass into bio-based chemicals and fuels. At present, bio-furan derivatives are generally obtained from cellulose and hemicellulose fractions of biomass via the acid-catalyzed dehydration of their relative C6-C5 sugars and then converted into a wide range of products. Furfural (FUR) and 5-hydroxymethylfurfural (HMF) are surely the most used furan-based feedstocks since their chemical structure allows the preparation of various high-value-added chemicals. Among several well-established catalytic approaches, hydrogenation and oxygenation processes have been efficiently adopted for upgrading furans; however, harsh reaction conditions are generally required. In this review, we aim to discuss the conversion of biomass derived FUR and HMF through unconventional (transfer hydrogenation, photocatalytic and electrocatalytic) catalytic processes promoted by heterogeneous catalytic systems. The reaction conditions adopted, the chemical nature and the physico-chemical properties of the most employed heterogeneous systems in enhancing the catalytic activity and in driving the selectivity to desired products are presented and compared. At the same time, the latest results in the production of FUR and HMF through novel environmental friendly processes starting from lignocellulose as well as from wastes and by-products obtained in the processing of biomass are also overviewed.

Background: Non-enzymatic browning (NEB) is the main quality defect in shelf-stable orange juice and other fruit juices during storage. Previous studies on NEB focused solely on the soluble fraction of orange juice, regardless of the fact that both soluble and insoluble fractions turn brown during extended storage. Clear evidence of the relative contribution of both fractions to NEB is currently lacking in the literature. This study investigated the contribution of the soluble and insoluble fractions of orange juice, which were obtained by centrifugation and ethanol precipitation, to NEB during storage. Changes in different NEB-related attributes, such as ascorbic acid (AA) degradation, and the browning index (BI), were quantified and kinetically modeled., Results: Evaluation of color during storage showed that the orange juice and the soluble compound-containing fractions turned brown whereas the insoluble fractions did not. The soluble compound-containing fractions showed exactly the same browning behavior with storage as the plain orange juice. Based on the kinetic parameters obtained, the degradation of AA, the hydrolysis of sucrose, the increase in the glucose and fructose content, and the formation of furfural and 5-hydroxymethylfurfural during storage were similar for the plain orange juice and the soluble compound-containing fractions., Conclusion: This work provided evidence that the soluble fraction of orange juice plays the major role in NEB, unlike the insoluble fraction, which seems to make no contribution. Results from this work also demonstrate the potential use of the soluble fraction as an orange-juice-based model system of reduced complexity that can be used for the further investigation of NEB processes. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

5-Hydroxymethylfurfural (HMF) can readily form by acid-catalyzed transformations of various sugars such as fructose, sucrose and to a lesser degree glucose, and is known to widely exist in various sugar-containing consumer products. Thus the potential health effect of HMF has been a subject of intensive studies. There have been earlier reports of HMF's undesirable effects at or above high micromolar concentrations. In this study, HMF is found to stimulate the H 1 receptor in vivo and in vitro. When assessed in cell culture and animal models, HMF was found to cause deformation of in cell culture studies of HUVECs at 50 μM, to increase the vascular permeability of paw skin at 1.0 mg/mL, and trigger symptoms of anaphylaxis in animal models at 32.5 μg/kg. At the molecular level, HMF was found to induce the release of NO and related cytokines, and trigger H 1 receptor-mediated inflammatory responses. Mutation studies also suggest the binding sites for HMF on the H 1 receptor. The findings described suggest the need for close monitoring of HMF contents in consumer products and their related side effects., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Aquaporin-1 (AQP1) dual water and ion channels enhance migration and invasion when upregulated in leading edges of certain classes of cancer cells. Work here identifies structurally related furan compounds as novel inhibitors of AQP1 ion channels. 5-Hydroxymethyl-2-furfural (5HMF), a component of natural medicinal honeys, and three structurally related compounds, 5-nitro-2-furoic acid (5NFA), 5-acetoxymethyl-2-furaldehyde (5AMF), and methyl-5-nitro-2-furoate (M5NF), were analyzed for effects on water and ion channel activities of human AQP1 channels expressed in Xenopus oocytes. Two-electrode voltage clamp showed dose-dependent block of the AQP1 ion current by 5HMF (IC 50 0.43 mM), 5NFA (IC 50 1.2 mM), and 5AMF (IC 50 ∼3 mM) but no inhibition by M5NF. In silico docking predicted the active ligands interacted with glycine 165, located in loop D gating domains surrounding the intracellular vestibule of the tetrameric central pore. Water fluxes through separate intrasubunit pores were unaltered by the furan compounds (at concentrations up to 5 mM). Effects on cell migration, invasion, and cytoskeletal organization in vitro were tested in high-AQP1-expressing cancer lines, colon cancer (HT29) and AQP1-expressing breast cancer (MDA), and low-AQP1-expressing SW480. 5HMF, 5NFA, and 5AMF selectively impaired cell motility in the AQP1-enriched cell lines. In contrast, M5NF immobilized all the cancer lines by disrupting actin cytoskeleton. No reduction in cell viability was observed at doses that were effective in blocking motility. These results define furans as a new class of AQP1 ion channel inhibitors for basic research and potential lead compounds for development of therapeutic agents targeting aquaporin channel activity. SIGNIFICANCE STATEMENT: 5-Hydroxymethyl-2-furfural (5HMF), a component of natural medicinal honeys, blocks the ion conductance but not the water flux through human Aquaporin-1 (AQP1) channels and impairs AQP1-dependent cell migration and invasiveness in cancer cell lines. Analyses of 5HMT and structural analogs demonstrate a structure-activity relationship for furan compounds, supported by in silico docking modeling. This work identifies new low-cost pharmacological antagonists for AQP1 available to researchers internationally. Furans merit consideration as a new class of therapeutic agents for controlling cancer metastasis., (Copyright © 2020 by The American Society for Pharmacology and Experimental Therapeutics.)

Further development of biomass conversions to viable chemicals and fuels will require improved atom utilization, process efficiency, and synergistic allocation of carbon feedstock into diverse products, as is the case in the well-developed petroleum industry. The integration of biological and chemical processes, which harnesses the strength of each type of process, can lead to advantaged processes over processes limited to one or the other. This synergy can be achieved through bioprivileged molecules that can be leveraged to produce a diversity of products, including both replacement molecules and novel molecules with enhanced performance properties. However, important challenges arise in the development of bioprivileged molecules. This review discusses the integration of biological and chemical processes and its use in the development of bioprivileged molecules, with a further focus on key hurdles that must be overcome for successful implementation.

The development of a simple and durable catalytic system for the production of chemicals from a high concentration of a substrate is important for biomass conversion. In this manuscript, 5-hydroxymethylfurfural (HMF) was converted to 1-hydroxy-2,5-hexanedione (HHD) using the combination of commercial Pd/C and acetic acid (AcOH) in water. The influence of temperature, H 2 pressure, reaction time, catalyst amount and the concentration of AcOH and HMF on this transformation was investigated. A 68% yield of HHD was able to be obtained from HMF at a 13.6 wt% aqueous solution with a 98% conversion of HMF. The resinification of intermediates on the catalyst was characterized to be the main reason for the deactivation of Pd/C. The reusability of the used Pd/C was studied to find that most of the activity could be recovered by being washed in hot tetrahydrofuran.

The formation of 6-(hydroxymethyl)pyridin-3-ol by ring expansion of 5-(hydroxymethyl)furfural (HMF) in the presence of ammonia-producing compounds was studied to determine the routes of formation of pyridin-3-ols in foods. 6-(Hydroxymethyl)pyridin-3-ol was produced from HMF in model systems, mostly at neutral pH values, as a function of reaction times and temperature and with an activation energy ( E a ) of 74 ± 3 kJ/mol, which was higher than that of HMF disappearance (43 ± 4 kJ/mol). A reaction pathway is proposed, which is general for the formation of pyridin-3-ols from 2-oxofurans. Thus, it explains the conversions of furfural into pyridin-3-ol and of 2-acetylfuran into 2-methylpyridin-3-ol, which were also studied. When honey and sugarcane honey were heated, they produced different pyridin-3-ols, although 6-(hydroxymethyl)pyridin-3-ol was the pyridine-3-ol produced to the highest extent. Obtained results suggest that formation of pyridin-3-ols in foods is unavoidable when 2-oxofurans are submitted to thermal heating and ammonia (or ammonia-producing compounds) is present.

Acrylamide, acrolein, and 5-hydroxymethylfurfural (HMF) are food-borne toxicants produced during the thermal processing of food. The α,β-unsaturated carbonyl group or aldehyde group in their structure can react easily with the amino, imino, and thiol groups in amino acids, proteins, and DNA via Michael addition and nucleophilic reactions in food and in vivo . This work reviews the interaction pathways of three toxins with amino acids and the cytotoxicity and changes after the digestion and absorption of the resulting adducts. Their interaction with DNA is also discussed. Amino acids ubiquitously exist in foods and are added as nutrients or used to control these food-borne toxicants. Hence, the interaction widely occurring in foods would greatly increase the internal exposure of these toxins and their derived compounds after food intake. This review aims to encourage further investigation on toxin-derived compounds, including their types, exposure levels, toxicities, and pharmacokinetics.

Ginseng (G) and Prepared Rehmannia Root (PRR) are commonly used in traditional Chinese medicine for blood supplementation. This study aimed to study G and PRR with different compatibility ratios changes in chemical composition and inhibition of cyclophosphamide-induced myelosuppression. HPLC was used to determine the chemical constituents of 13 ginsenosides, 5-hydroxymethylfurfural (5-HMF) and verbascoside in different proportions of G-PRR. Balb/c mice were injected intraperitoneally with cyclophosphamide (CTX) to induce bone marrow suppression. The effects of different proportions of G-PRR on peripheral blood, bone marrow nucleated cells, thymus and spleen index of myelosuppressed mice were analyzed. The results showed that the compatibility of G and PRR can promote the dissolution of ginsenosides, and the content of conventional ginsenosides decreased, and the content of rare ginsenosides increased. Different proportions of G-PRR increased the number of peripheral blood and bone marrow nucleated cells in cyclophosphamide-induced bone marrow suppression mice (p < 0.01), increased thymus index (p < 0.01), decreased spleen index (p < 0.01). Different proportions of G-PRR can improve the myelosuppression induced by cyclophosphamide in mice, and the combined effect of G-PRR is better than the single decoction of G and PRR. Among them, G-PRR 2 : 3 and G-PRR 1 : 2 were better than the other groups. These results indicate that different proportion of G-PRR can improve bone marrow suppression, and the combined decoction of G-PRR is better than the separate Decoction in improving bone marrow suppression. This improvement may be related to the changes of the substance basis and active ingredients of G-PRR.

Chemical manufacturing involves carbon sources releasing CO 2 into the atmosphere. By contrast, seaweeds are carbon sinks that can absorb released CO 2 and therefore have great potential for use as feedstocks in sustainable chemical manufacturing. In particular, seaweeds could contribute to mitigating vast amounts of global CO 2 emissions. Accordingly, seaweeds could be an excellent candidate biomaterial for sustainable production of hydroxymethylfurfural (HMF), called a 'sleeping giant' platform chemical due to its wide versatility in chemical manufacturing. HMF is produced through sugar dehydration mechanisms, and seaweed storage glucans comprised of glucose can be appropriate feeding substrates for its production. This opinion article introduces a new opportunity for sustainable production of HMF using storage glucan-rich seaweeds., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

5-Hydroxymethylfurfural (5-HMF) is present in numerous carbohydrate-containing consumer products and is readily converted into two oligomers (II and III) by acid-catalyzed transformations. Previous studies have demonstrated various undesirable effects of 5-HMF at relatively high concentrations. In this study, we demonstrate that 5-HMF and its two oligomers exert neurotoxic effects in vivo and in vitro. All three substances blocked the proliferation of PC12 and HT22 cells at the S or G2-M phase in dose- and time-dependent manners. In addition, [Ca 2+ ]i and reactive oxygen species levels were both significantly increased by treatment with these substances at 100 μM, individually, compared with the control group. Although no motor and cognitive deficits are observed, 5-HMF and III can induce anxiety- and depression-like behavior in adolescent mice at administered doses of 0.15 mg kg -1 and 1.5 mg kg -1 in vivo, which are close to or less than the reported 24 h dietary intake of 5-HMF in humans. Together, our findings suggest the need for close monitoring of the content of these substances in food, as well as the need for studies on the effects of long-term exposure to them.

The incidence of adverse reactions in food is very low, however, some food products contain toxins formed naturally due to their handling, processing and storage conditions. 5-(Hydroxymethyl)-2-furfural (HMF) can be formed by hydrogenation of sugar substances in some of manufactured foodstuffs and honey under elevated temperatures and reduced pH conditions following Maillard reactions. In previous studies, it was found that HMF was responsible for harmful (mutagenic, genotoxic, cytotoxic and enzyme inhibitory) effects on human health. HMF occurs in a wide variety of food products like dried fruit, juice, caramel products, coffee, bakery, malt and vinegar. The formation of HMF is not only an indicator of food storage conditions and quality, but HMF could also be used as an indicator of the potential occurrence of contamination during heat-processing of some food products such as coffee, milk, honey and processed fruits. This review focuses on HMF formation and summarizes the adverse effects of HMF on human health.

New Zealand manuka honeys are known for their propensity to increase apparent C4 sugar content during storage. Depending on the particular storage regime and the initial content of dihydroxyacetone (DHA) in honey, the ready-to-market product often fails the C4 sugar test because of the above phenomenon. We have used DHA labeled with a radioactive 14 C isotope in a set of honeys subject to an incubation experiment. These honeys were analyzed for DHA, methylglyoxal (MG), hydroxymethylfurfural (HMF), apparent C4 sugars, and 14 C scintillation counts over a period of 18 months. The major conclusion of this experiment is that neither DHA nor MG is responsible for the δ 13 C shift in the honey protein extract. There must be some other yet unknown substance of manuka honey, which binds to the protein and causes negative δ 13 C shift. One identified candidate for such a binding is carbon dioxide.

Biobased plasticizers, as substitutes for phthalates, have been synthesized from 5-hydroxymethylfurfural (HMF) and carboxylic acids (or esters) through a chemoenzymatic cascade process that involves as its first step the reduction of 5-hydroxymethylfurfural into 2,5-bis(hydroxymethyl)furan (BHMF), followed by the esterification of BHMF with carboxylic acids (or esters) by using a supported lipase (Novozym 435). The reduction of HMF into BHMF is performed by using monodisperse metallic Co nanoparticles with a thin carbon shell (Co@C) with high activity and selectivity. After optimization of reaction conditions (temperature, hydrogen pressure, and solvent), it is possible to achieve 97 % conversion of HMF with 99 % selectivity to BHMF after 2 h reaction time. The reduction of HMF and esterification of BHMF using carboxylic acids or vinyl esters as acyl donors by lipase are optimized separately in batch and in fixed-bed continuous reactors. The coupling of two flow reactors (for reduction and subsequent esterification) working under optimized reaction conditions affords the diesters of BHMF in roughly 90 % yield with no loss of activity during 60 h of operation., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Jabara ( Citrus jabara Hort. ex Y. Tanaka) is a type of citrus fruit known for its beneficial effect against seasonal allergies. Jabara is rich in the antioxidant narirutin whose anti-allergy effect has been demonstrated. One of the disadvantages in consuming Jabara is its bitter flavor. Therefore, we fermented the fruit to reduce the bitterness and make Jabara easy to consume. Here, we examined whether fermentation alters the anti-allergic property of Jabara. Suppression of degranulation and cytokine production was observed in mast cells treated with fermented Jabara and the effect was dependent on the length of fermentation. We also showed that 5-hydroxymethylfurfural (5-HMF) increases as fermentation progresses and was identified as an active component of fermented Jabara, which inhibited mast cell degranulation. Mast cells treated with 5-HMF also exhibited reduced degranulation and cytokine production. In addition, we showed that the expression levels of phospho-PLC γ 1 and phospho-ERK1/2 were markedly reduced upon FcεRI stimulation. These results indicate that 5-HMF is one of the active components of fermented Jabara that is involved in the inhibition of mast cell activation.

This paper demonstrates an integrated zero liquid discharge (ZLD) process for time-dependent recovery of 5-hydroxymethyl furfural (HMF), levulinic acid (LA) and potassium, nitrogen and sulphur rich mother liquor (KNS-ML) - manure from agar/agarose containing seaweed aqueous solution using transition metal-free KHSO 4 as an eco-friendly and reusable catalyst. The selectivity of HMF is higher at 115 °C in 3 h and favorable to LA in 6 h in autoclave conditions. The proposed concept could be fine-tuned for the selective production of 5-HMF (up to 91% yield) or levulinic acid (56% yield) in the presence of the KHSO 4 catalyst. We have also achieved recyclability of KHSO 4 up to nine (09) cycles and the gram-scale reaction has been demonstrated. The (KNS-ML) obtained after nine cycles followed by neutralization with ammonia solution utilized for manure makes the process zero-liquid discharge and more cost-effective. The efficacy of the KNS-ML after nine cycles has been tested on groundnut plants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this study, chemoenzymatic synthesis of furfuryl alcohol from biomass (e.g., corncob, bamboo shoot shell, and rice straw) was attempted by the tandem catalysis with Lewis acid (SnCl 4 or solid acid SO 4 2- /SnO 2 -bentonite) and biocatalyst in one-pot manner. Compared with SnCl 4 , solid acid SO 4 2- /SnO 2 -bentonite had higher catalytic activity for converting biomass into furfural, which could be biologically converted into furfuryl alcohol with Escherichia coli CCZU-H15 whole-cell harboring reductase activity. Sequential catalysis of biomass into furfural with SO 4 2- /SnO 2 -bentonite (3.0 wt%) at 170 °C for 0.5 h and bioreduction of furfural with whole cells at 30 °C for 4.5 h were used for the effective synthesis of furfuryl alcohol in one-pot media. Corncob, bamboo shoot shell, and rice straw (3.0 g, dry weight) could be converted into 65.7, 50.3, and 58.5 mM furfuryl alcohol with the yields of 0.26, 0.25, and 0.23 g furfuryl alcohol/(g xylan in biomass) in 40 mL reaction media. Finally, an efficient process of recycling and reusing of SO 4 2- /SnO 2 -bentonite catalyst and immobilized whole-cell biocatalyst was developed for the chemoenzymatic synthesis of furfuryl alcohol from biomass in the one-pot reaction system.

Catalytic transformation of biomass-derived furans into value-added chemicals and biofuels has received considerable interest recently. In this work, aldehyde dehydrogenases (ALDHs) were identified from Comamonas testosteroni SC1588 for the oxidation of bio-based furans into furan carboxylic acids. Of the whole-cell biocatalysts constructed, Escherichia coli expressing a vanillin dehydrogenase (E. coli&#95;CtVDH1) proved to be the best for the oxidation of 5-hydroxymethylfurfural (HMF). 5-Hydroxymethyl-2-furancarboxylic acid (HMFCA) was obtained in the yield of approximately 92 % within 12 h using this recombinant strain when the HMF concentration was up to 200 mM. In a fed-batch process, 292 mM of HMFCA was produced within 20.5 h, thereby providing a productivity as high as 2.0 g/L h. Other furan carboxylic acids were synthesized in the yields of 83-95%. Besides, the partially purified HMF was smoothly converted into HMFCA by this recombinant strain, with a 90% yield., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Our previous research showed that thioacetal and Schiff base formed between 5-hydroxymethylfurfural (HMF) and cysteine or lysine considerably decreased the cytotoxicity of HMF. In this study, two adol condensation adducts, named 2β-amino-3α-hydroxy-3-(5-(hydroxymethyl)furan-2-yl)propanoic acid (HGA) and 2α-amino-3β-hydroxy-3-(5-(hydroxymethyl)furan-2-yl)propanoic acid (HGB), were prepared from the reaction products of glycine and HMF, and their cytotoxicities were investigated in Caco-2 cells. Compared with HMF, HGA and HGB displayed lower cytotoxicities against Caco-2 cells with IC 50 values of 36.50 and 43.47 mM, respectively, versus 16.11 mM (HMF). In contrast to our findings in thioacetal and Schiff base products, HGA and HGB underwent a very high metabolism rate (99%) in Caco-2 cells. HGA and HGB may degrade to other products instead of HMF since no extracellular or intracellular HMF was detected.

Thermal treatment of food leads to the formation of melanoidins by reactions of carbohydrates with free amino acids or proteins in the late stage of Maillard reaction. The aim of this study was the identification of reaction mechanisms responsible for the formation of melanoidins involving active methylenes with the heterocyclic structure and the structural characterization of the resulting products. For this purpose, norfuraneol was incubated with the aldehydes pyrrole-2-aldehyde or furfural at 125 °C. With the help of high-resolution mass spectrometry, the structural composition of oligomers of up to fifteen C 5 -units could be described for the first time. Aldol and Michael reactions could be identified as crucial steps for the formation of new C-C-bonds. With increasing heating time, the elimination of water from the products was facilitated, and oxidation reactions of integrated reductone structures lead to the expansion of conjugated double-bond systems responsible for the color formation of the samples.

Background: Non-enzymatic glycation of proteins plays a significant role in the pathogenesis of secondary diabetic complications via the formation of advanced glycation end products (AGEs) and increased oxidative stress. Methylglyoxal (MG), a highly reactive dicarbonyl of class α-oxoaldehyde that generates during glucose oxidation and lipid peroxidation, contributes to glycation., Objective: This comparative study focuses on methylglyoxal induced glycoxidative damage suffered by immunoglobulin G (IgG) and fibrinogen, and to unveil implication of structural modification of serum proteins in diabetes-associated secondary complications., Methods: The methylglyoxal induced structural alterations in IgG and fibrinogen were analyzed by UVvis, fluorescence, circular dichroism and Fourier transform infrared (FT-IR) spectroscopy. Ketoamine moieties, carbonyl contents, 5-Hydroxymethylfurfural (HMF) and malondyaldehyde were also quantified. Free lysine and arginine estimation, detection of non-fluorogenic carboxymethyllysine (CML) and fibril formation were confirmed by thioflavin T (ThT) assay., Results: Structural alterations, increased carbonyl contents and ketoamines were reported in MG glycated IgG and fibrinogen against their native analogues., Conclusion: The experiment results validate structural modifications, increased oxidative stress and AGEs formation. Thus, we can conclude that IgG-AGEs and Fib-AGEs formed during MG induced glycation of IgG and fibrinogen could impede normal physiology and might initiates secondary complications in diabetic patients., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The non-enzymatic glycosylation is a very common phenomenon in the physiological conditions which is mediated by distinct chemical entities containing reactive carbonyl species (RCS) and participates in the modification of various macromolecules particularly proteins. To date, various carbonyl species, i.e., glucose, fructose, D-ribose and methylglyoxal have been used frequently to assess the in-vitro non-enzymatic glycosylation. Similarly, 2'-Deoxyribose is one of the most abundant reducing sugar of the living organisms which forms the part of deoxyribonucleic acid and may react with proteins leading to the production of glycation intermediates, advanced glycation end products (AGEs) and highly reactive RCS. Thymidine phosphorylase derived degradation of thymidine contributes to the formation of 2'-Deoxyribose, therefore, acting as a major source of cellular 2'- Deoxyribose. Since albumin is a major serum protein which plays various roles including binding and transporting endogenous and exogenous ligands, it is more prone to be modified through different physiological modifiers; therefore, it may serve as a model protein for in-vitro experiments to study the effect of 2'Deoxyribose mediated modifications in the protein. In this study, Bovine Serum Albumin (BSA) was glycated with 50 and 100 mM 2'-Deoxyribose followed by examining secondary and tertiary structural modifications in BSA as compared to its native (unmodified) form by using various physicochemical techniques. We evident a significant modification in 2'-Deoxyribose-glycated BSA which was confirmed through increased hyperchromicity, keto amine moieties, carbonyl and hydroxymethylfurfural content, fluorescent AGEs, altered secondary structure conformers (α helix and β sheets), band shift in the amide-I region and diminished free lysine and free arginine content. These modifications were reported to be higher in 100 mM 2'-Deoxyribose-glycated BSA than 50 mM 2'- Deoxyribose-glycated BSA. Our findings also demonstrated that the rate of glycation is positively affected by the increased concentration of 2'-Deoxyribose. The results of the performed study can be implied to uncover the phenomenon of serum protein damage caused by 2'-Deoxyribose leading towards diabetic complications and the number of AGE-related diseases., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

A polar modified post-cross-linked poly (divinylbenzene-co-ethyleneglycol-dimethacrylate) (PCL-PDE) resin was synthesized by suspension polymerization of ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB), and a post-cross-linked reaction. After characterization, the adsorption behaviors of 5-hydroxymethylfurfural (5-HMF) on PCL-PDE resin were determined in comparison with the starting copolymers PDE resin. The equilibrium adsorption capacity of 5-HMF on PCL-PDE resin was much larger than PDE resin and the increase rate was greater than 52.6%. The equilibrium data of 5-HMF onto PCL-PDE resin were found to be better fitted by the Langmuir isotherm model. The kinetic data shows that the adsorption reached equilibrium in a short time (less than 20 min) can be fitted by the pore diffusion model (PDM) at various operating conditions. The effective pore diffusion coefficient was dependent upon adsorption temperature, and were 6.706 × 10 -10 , 8.958 × 10 -10 , 1.136 × 10 -9 and 1.429 × 10 -9  m 2  s -1 at 288, 298, 308 and 318 K, respectively. Furthermore, the effects of feed flow rate (Q f  = 0.6, 1.5, 3.0 and 6.0 mL min -1 ) and initial 5-HMF concentration (c f  = 0.52, 1.02, 2.00 and 4.96 g L -1 ) on the adsorption were investigated systematically. Besides, a general rate model (GRM) was used to predict adsorption breakthrough curves of 5-HMF. The simulation results are highly consistent with the experimental data, indicating that the GRM can successfully simulate this process. In the desorption process, the desorption capacity reaches 99.6% of adsorbed capacity, suggesting that the PCL-PDE resin exhibited good reusability. Therefore, it could be suggested that the PCL-PDE resin has a potential application in the separation and purification of 5-HMF., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Furan-2,5-dicarboxylic acid (FDCA) is a building block of biodegradable plastics that can be used to replace those derived from fossil carbon sources. In recent years, much interest has focused on the synthesis of FDCA from the bio-based 5-hydroxymethylfurfural (HMF) through a cascade of enzyme reactions. Aryl-alcohol oxidase (AAO) and 5-hydroxymethylfurfural oxidase (HMFO) are glucose-methanol-choline flavoenzymes that may be used to produce FDCA from HMF through three sequential oxidations, and without the assistance of auxiliary enzymes. Such a challenging process is dependent on the degree of hydration of the original aldehyde groups and of those formed, the rate-limiting step lying in the final oxidation of the intermediate 5-formyl-furancarboxylic acid (FFCA) to FDCA. While HMFO accepts FFCA as a final substrate in the HMF reaction pathway, AAO is virtually incapable of oxidizing it. Here, we have engineered AAO to perform the stepwise oxidation of HMF to FDCA through its structural alignment with HMFO and directed evolution. With a 3-fold enhanced catalytic efficiency for HMF and a 6-fold improvement in overall conversion, this evolved AAO is a promising point of departure for further engineering aimed at generating an efficient biocatalyst to synthesize FDCA from HMF., (Copyright © 2019 Elsevier B.V. All rights reserved.)

5-Acetoxymethyl-2-furfural (AMF) was prepared from D-fructose via 1,6-diacetylfructose (DAF) through a simple two-step reaction pathway. Immobilized enzyme (Novozym 435) was found to be the best enzymatic catalyst for the trans-esterification step (yielding 94.6% DAF). In the dehydration step, while soluble H 2 SO 4 was found to be the best acidic catalyst (yielding 86.6% AMF), we opted to utilize heterogeneous cation exchange resin (Amberlyst 15) together with recyclable industrial solvents (1,4-dioxane) for a more sustainable AMF synthesis procedure. Although the total yield of AMF was a little lower, both the enzyme and the solid acid catalyst could be recycled for five cycles without a significant loss of activity, which has a major contribution to the cost-efficient aspect of the entire process.

An efficient and environmentally friendly system for producing 5-hydroxymethylfurfural (5-HMF) from fructose has been proposed. Substrate concentration is an important factor for practical application of the process; however, use of a high concentration of fructose has rarely been tested in the reaction because the conditions accelerate intermolecular side reactions to form adhesive humins. Humin byproducts stuck on reactor surfaces can make the production of 5-HMF on an industrial scale difficult. Therefore, developing a catalytic reaction system that can promote the synthesis of 5-HMF from highly concentrated fructose without causing adhesion of humins to reactors is needed. The present study demonstrated that activated carbons are promising materials for this system. Activated carbon catalyzed the conversion of fructose to 5-HMF without adhesion of humins to reactor vessels under practical conditions of high substrate concentration up to 73.2%. The catalytic activity was determined not only by the amount of surface weakly acidic oxygenated groups but also by the adsorption of fructose. In addition, strong adsorption of 5-HMF led to low selectivity of 5-HMF and the formation of adhesive humins. This is the first report to describe the synthesis of 5-HMF from solutions containing a fructose concentration greater than 70%., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Hawthorn seed can be used to produce various bioactive compounds through destructive distillation. In this study, an accurate and feasible analytical method based on a gas chromatography mass spectrometer (GC-MS) was developed for simultaneous determination of six major compounds (contributing to more than 3% in total peak area) in destructive distillation extracts of hawthorn seed collected at different temperatures ranging from 150 to 270 °C. Then, a broth microdilution method coupled with grey correlation analysis was engaged in the evaluation of their antimicrobial activities and the screening of primarily active compounds. Results indicate that the extract collected from 211 to 230 °C had the highest content of six major compounds (furfural, 2-methoxyphenol, 2-methoxy-4-methylphenol, 4-ethyl-2-methoxyphenol, 2,6-dimethoxyphenol, and 5-tertbutylpyrogallol) and the strongest antibacterial activity. Besides, 2,6-dimethoxyphenol was found to be a potential compound in inhibiting the growth of vaginitis pathogens. This study provided an optimum temperature for the destructive distillation of hawthorn seed, reducing the waste of energy, and saving the cost of production in the hawthorn industry.

Determining acrylamide (AA) content in foods using chromatographic methods is expensive and time-consuming. Therefore, there is a need to develop a simple, economical method for monitoring the content of acrylamide in foods. This study analysed whether there is a relationship between acrylamide levels with some heat-induced parameters, such as 5-hydroxymethylfurfural (HMF) and browning, in order to assess their usefulness in predicting the potential acrylamide levels in market-purchased food. Sixty plant-based food products were tested. The correlation coefficients for AA levels with L*, a* and b* values and HMF content were significant ( p < 0.05) for French fries and potato chips. There was no statistically significant correlation between thermal-processing indexes (HMF and colour parameters) and acrylamide levels in commercial bread, breakfast cereals and biscuits. The results indicate that these classical thermal-processing indexes are not directly related to the acrylamide content in commercial cereal-based food and they cannot be indicators of AA level. Thus, the correlation between HMF and colour parameters with acrylamide content depends on the type of food and it is difficult to estimate the amount of AA based on these classical thermal-processing indexes of market-purchased food.

Furancarboxylic acids are promising biobased building blocks in pharmaceutical and polymer industries. In this work, dual-enzyme cascade systems composed of galactose oxidase (GOase) and alcohol dehydrogenases (ADHs) are constructed for controlled synthesis of 5-formyl-2-furancarboxylic acid (FFCA) and 2,5-furandicarboxylic acid (FDCA) from 5-hydroxymethylfurfural (HMF), based on the catalytic promiscuity of ADHs. The byproduct H 2 O 2 , which is produced in GOase-catalyzed oxidation of HMF to 2,5-diformylfuran (DFF), is used for horseradish peroxidase (HRP)-mediated regeneration of the oxidized nicotinamide cofactors for subsequent oxidation of DFF promoted by an ADH, thus implementing H 2 O 2 internal recycling. The desired products FFCA and FDCA are obtained with yields of more than 95 %., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The work described in this Research Communication concerns the production of Dulce de leche (DL), that is a traditional product from South America obtained by concentration. Maillard reaction (MR) products are mainly responsible for the formation of color and flavor in this product. Lactose-hydrolyzed products have been developed to supply consumer demand, but this hydrolysis may affect the flavor, color, taste, texture and even some nutritional aspects of the product. We studied the influence of different levels of lactose-hydrolysis, sucrose addition and initial pH on the development of MR, appraised by the determination of 5-hydroxymethylfurfural (HMF). A process simulator with multi-monitoring system was used to produce 15 DL. Box-Behnken 33 experimental design was applied for the three factors: pH, lactose-hydrolysis level and sucrose concentration. Lipids, protein, ashes, carbohydrates, water activity, dissolved solids, colorimetric analysis and HMF (free and total) are among the physicochemical attributes and MR indicators analyzed in this work. The products showed significant differences in composition but all the values were in agreement with the literature. Moreover, higher levels of lactose hydrolysis and higher pH presented a direct relation with the development of MR, observed by an increase in coloration (lower luminosity) and more formation of HMF, both free and total. The present study expands the knowledge about DL spread made of lactose-hydrolyzed milk, allowing the food industries to produce a lactose free DL with nutritional and sensory characteristics closer to the traditional product.

Fructooligosaccharides have important potential use in the food industry due to their properties such as solubility in water, stability in acidity of fruit juices and during storage, low-calorie value and prebiotic effects. In this study, for the first time, Zymomonas mobilis levansucrase was used for in situ 6-kestose production in carob molasses. The produced kestose was stable during storage at 20 °C for 4 months. The product was evaluated for color, non-enzymatic browning index and titratable acidity during storage and the quality of the product was found comparable to that of control. Furthermore, the decreased amount of sucrose resulted in the prevention of 5-hydroxymethylfurfural (5-HMF) formation during storage. As a result, carob molasses was converted into a high-quality prebiotic product with decreased sucrose content and reduced 5-HMF quantities, and a new method was developed to prevent 5-HMF formation in fruit juices and molasses., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Acrylamide and 5-hydroxymethyl-2-furfural (5-HMF) are two of the most abundant compounds generated during thermal processing. A simple method for the simultaneous quantitation of acrylamide and 5-HMF was developed and successfully applied in thermally processed foods. Acrylamide and 5-HMF were co-extracted with methanol and then purified and enriched by an Oasis HLB solid-phase extraction cartridge, simultaneously analyzed by high-performance liquid chromatography and detected with a diode array detector, respectively, at their optimal wavelength. The linear concentration range was found to be 25-5000 μg/L with high linear correlation coefficients (R > 0.999). The limit of detection and the limit of quantitation for acrylamide and 5-HMF were 6.90 μg/L and 4.66 μg/L, and 20.90 μg/L and 14.12 μg/L, respectively. The recovery of acrylamide and 5-HMF in biscuits, bread, Chinese doughnuts, breakfast cereals, and milk-based baby foods was achieved at 87.72-96.70% and 85.68-96.17% with RSD at 0.78-3.35% and 0.55-2.81%, respectively. The established method presents simplicity, accuracy and good repeatability, and can be used for the rapid simultaneous quantitation of acrylamide and 5-HMF in thermally processed foods.

Acting as a "green" manufacturing route, the enzyme toolbox made up of galactose oxidase, catalase, and horseradish peroxidase can achieve a satisfactory yield of 2,5-diformylfuran derived from 30 mM hydroxymethylfurfural. However, as the concentration of hydroxymethylfurfural increases, the substrate causes oxidative damage to the activity of the tri-enzyme system, and the accumulated hydrogen peroxide produced by galactose oxidase causes tri-enzyme inactivation. The cost of tri-enzymes is also very high. These problems prevent the utilization of this enzyme toolbox in practice. To address this, galactose oxidase, catalase, and horseradish peroxidase were co-immobilized into Cu 3 (PO 4 ) 2 nanoflowers in this study. The resulting co-immobilized tri-enzymes possessed better tolerance towards the oxidative damage caused by hydroxymethylfurfural at high concentrations, as compared to free tri-enzymes. Moreover, the 2,5-diformylfuran yield of co-immobilized tri-enzymes (95.7 ± 2.7%) was 1.06 times higher than that of separately immobilized enzymes (90.4 ± 1.9%). This result could be attributed to the boosted protective effect provided by catalase to the activity of galactose oxidase, owing to the physical proximity between them on the same support. After 30 recycles, co-immobilized tri-enzymes still achieves 86% of the initial yield. Moreover, co-immobilized tri-enzymes show enhanced thermal stability compared with free tri-enzymes. This work paves the way for the production of 2,5-diformylfuran from hydroxymethylfurfural via co-immobilized tri-enzymes.

Treating large acute or chronic wounds remains a challenging task because of a lack of effective methods to accelerate wound healing. Though growth factor-based wound products are found to be effective, they are costly and are potentially associated with increased cancer mortality. Effective, safe, and affordable strategies to tackle large or chronic wounds need to further be designed and developed. Here, we designed a new antioxidant-embedded hydrogel system for speeding up the wound healing process. We prepared multifunctional poly (vinyl alcohol)/sodium alginate (PVA/SA) hydrogels with the incorporation of 5-hydroxymethylfurfural (5-HMF) and silver nanoparticles (Ag-NPs), and investigated their physiochemical and biological properties in vitro and in vivo. PVA, SA, 5-HMF, and Ag-NPs were employed for good mechanical properties, good biocompatibility, anti-inflammation, and anti-bacterial activity, respectively. 5-HMF is commonly found in many food products (e.g. honey, coffee, and black garlic) and is known as an antioxidant. In our in vitro study, 5-HMF was found to effectively facilitate the proliferation and migration of human skin fibroblasts (HSF), and collagen production. Besides, 5-HMF-embedded PVA/SA hybrid hydrogels supported controlled release and good cell compatibility, and more importantly accelerated wound healing in vivo through ameliorated inflammation, enhanced angiogenesis/vascularization, increased collagen production, and promoted re-epithelialization., (Copyright © 2019 Elsevier B.V. All rights reserved.)