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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.

The present paper reviews recent advances on the direct synthesis of 5-hydroxymethylfurfural (HMF) from different kinds of raw biomasses. In particular, in the paper HMF production from: (i) edible biomasses; (ii) non-edible lignocellulosic biomasses; (iii) food wastes (FW) have been reviewed. The different processes and catalytic systems have been reviewed and their merits, demerits and requirements for commercialisation outlined.

The development of precious-metal-free catalysts to promote the sustainable production of fuels and chemicals from biomass remains an important and challenging target. Here, we report the efficient hydrogenolysis of biomass-derived 5-hydroxymethylfurfural to 2,5-dimethylfuran over a unique core-shell structured catalyst, Co@CoO that affords the highest productivity among all catalysts, including noble-metal-based catalysts, reported to date. Surprisingly, we find that the catalytically active sites reside on the shell of CoO with oxygen vacancies rather than the metallic Co. The combination of various spectroscopic experiments and computational modelling reveals that the CoO shell incorporating oxygen vacancies not only drives the heterolytic cleavage, but also the homolytic cleavage of H 2 to yield more active H δ− species, resulting in the exceptional catalytic activity. Co@CoO also exhibits excellent activity toward the direct hydrodeoxygenation of lignin model compounds. This study unlocks, for the first time, the potential of simple metal-oxide-based catalysts for the hydrodeoxygenation of renewable biomass to chemical feedstocks. The development of precious-metal-free catalysts to promote the sustainable production of fuels and chemicals from biomass challenging. Here the authors report a unique core-shell structured Co@CoO catalyst which exhibits excellent performance in the hydrogenolysis of biomass-derived compounds.

Introduction: 5-HMF is a molecule found in carbohydrate-rich foods that is associated not only with cancer and anaphylactic reactions, but also with anti-oxidant properties. Questions arose as to whether 5-HMF exhibited a catalytic effect in relation to lipid peroxidation and lipoprotein oxidation in presence of metals and/or radicals. Methods: Peroxynitrite (ONOO−)-induced chemiluminescence and ONOO− nitration of tyrosine residues on BSA using anti-nitro-tyrosine-antibodies were used to measure the protection of 5-HMF against peroxides or nitration compared to vitamin C (VitC). The reductive potential of 5-HMF or VitC on Cu2+ or Fe3 was estimated using the bicinchoninic acid (BCA) or Fenton-complex method. Human plasma was used to measure the generation of malondialdehyde (MDA), 4-hydroxynonenal (HNE), and total thiols after Fe2+/H2O2 oxidation in the presence of different concentrations of 5-HMF or VitC. Finally, Cu2+ oxidation of LDL after 4 h was carried out with 5-HMF or VitC, measuring the concentration of MDA in LDL with the thiobarbituric assay (TBARS). Results: VitC was 4-fold more effective than 5-HMF in scavenging ONOO− to nearly 91.5% at 4 mM, with the exception of 0.16 mM, where the reduction of ONOO− by VitC was 3.3-fold weaker compared to 0.16 mM 5-HMF. VitC or 5-HMF at a concentration of 6 mM inhibited the nitration of tyrosine residues on BSA to nearly 90% with a similar course. While 5-HMF reduced free Fe3+ in presence of phenanthroline, forming Fe2+ (phenantroleine)3 [Fe2+(phe)3] or complexed Cu2+(BCA)4 to Cu+(BCA)4 weakly, VitC was 7- to 19-fold effective in doing so over all the used concentrations (0–25 mM). A Fe2+—H2O2 solution mixed with human plasma showed a 6–10 times higher optical density (OD) of MDA or HNE in the presence of 5-HMF compared to VitC. The level of thiols was significantly decreased in the presence of higher VitC levels (1 mM: 198.4 ± 7.7 µM; 2 mM: 160.0 ± 13.4 µM) compared to equal 5-HMF amounts (2562 ± 7.8 µM or 242.4 ± 2.5 µM), whereas the usage of lower levels at 0.25 µM 5-HMF resulted in a significant decrease in thiols (272.4 ± 4.0 µM) compared to VitC (312.3 ± 19.7 µM). Both VitC and 5-HMF accelerated copper-mediated oxidation of LDL equally: while the TBARS levels from 4 h oxidized LDL reached 137.7 ± 12.3 nmol/mg, it was 1.7-fold higher using 6 mM VitC (259.9 ± 10.4 nmol/mg) or 6 mM 5-HMF (239.3 ± 10.2 nmol/mg). Conclusions: 5-HMF appeared to have more pro-oxidative potential compared to VitC by causing lipid peroxidation as well as protein oxidation.

Furfural is a renewable platform compound that can be derived from lignocellulosic biomass. The highly functionalized molecular structure of furfural enables us to prepare a variety of high value-added chemicals, which will help realize biomass high-value utilization, and alleviate energy and environmental problems. This paper reviews the research progress on furfural production and upgrading to C5 chemicals from the catalyst perspective. The emphasis is placed on summarizing and refining the catalytic mechanism and in-depth analysis of available data. Specifically, the reaction mechanism of furfural production and upgrading is summarized firstly from the perspective of reaction pathways and reaction kinetics. Then, the available data are further processed to evaluate the actual reaction efficiency of different catalytic systems from multiple dimensions. Finally, based on statistical analysis, the challenges and opportunities of furfural-based research are proposed.

Nitrogen-containing compounds, especially primary amines, are vital building blocks in nature and industry. Herein, a protocol is developed that shows in situ formed N-formyl quasi-catalytic species afford highly selective synthesis of formamides or amines with controllable levels from a variety of aldehyde- and ketone-derived platform chemical substrates under solvent-free conditions. Up to 99% yields of mono-substituted formamides are obtained in 3 min. The C-N bond formation and N-formyl species are prevalent in the cascade reaction sequence. Kinetic and isotope labeling experiments explicitly demonstrate that the C-N bond is activated for subsequent hydrogenation, in which formic acid acts as acid catalyst, hydrogen donor and as N-formyl species source that stabilize amine intermediates elucidated with density functional theory. The protocol provides access to imides from aldehydes, ketones, carboxylic acids, and mixed-substrates, requires no special catalysts, solvents or techniques and provides new avenues for amination chemistry. Processes for efficient production of primary, secondary or ternary aminated compounds are constant challenges for chemical and pharmaceutical industries. Here, the authors develop selective and sustainable amination chemistry widely applicable to chemical substrates via formic acid.

Biobased furans have emerged as chemical building blocks for the development of materials because of their diverse scaffolds and as they can be directly prepared from sugars. However, selective, efficient, and cost-effective scalable conversion of biobased furans remains elusive. Here, we report a robust transaminase (TA) from Shimia marina (SMTA) that enables the scalable amination of biobased furanaldehydes with high activity and broad substrate specificity. Crystallographic and mutagenesis analyses provide mechanistic insights and a structural basis for understanding SMTA, which enables a higher substrate conversion. The enzymatic cascade process established in this study allows one-pot synthesis of 2 ,5 - bis (aminomethyl)furan (BAMF) and 5 -(aminomethyl)furan- 2 -carboxylic acid from 5 -hydroxymethylfurfural. The biosynthesis of various furfurylamines, including a one-pot cascade reaction for BAMF generation using whole cells, demonstrates their practical application in the pharmaceutical and polymer industries. Biobased furans are important chemical building blocks for the development of materials, but selective, efficient, and cost-effective scalable conversion of biobased furans remains elusive. Here, the authors report a transaminase from Shimia marina (SMTA) that enables the scalable amination of biobased furanaldehydes with high activity and broad substrate specificity and provide structural and mechanistic insights into SMTA activity.

The aim of this paper is to evaluate the protective effect of 5-hydroxymethyl-2-furfural (5-HMF) on acute alcohol-induced liver oxidative injury in mice. 5-HMF, a maillard reaction product, was isolated from the fruits of Schisandra chinensis for animal experiments. Experimental ICR mice were pretreated with different doses of 5-HMF (7.5, 15, and 30 mg/kg) for seven days by gavage feeding. Biochemical markers and enzymatic antioxidants from serum and liver tissue were examined. Our results showed that the activities of ALT (alanine aminotransferase), AST (aspartate transaminase), TC (total cholesterol), TG (triglyceride), L-DLC (low density lipoprotein) in serum and the levels of MDA (malondialdehyde) in liver tissue, decreased significantly (p < 0.05) in the 5-HMF-treated group compared with the alcohol group. On the contrary, enzymatic antioxidants CAT (catalase), GSH-Px (glutathione peroxidase), and GSH SOD (superoxide dismutase) were markedly elevated in liver tissue treated with 5-HMF (p < 0.05). Furthermore, the hepatic levels of pro-inflammatory response marker tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) were significantly suppressed (p < 0.05). Histopathological examination revealed that 5-HMF (30 mg/kg) pretreatment noticeably prevented alcohol-induced hepatocyte apoptosis and fatty degeneration. It is suggested that the hepatoprotective effects exhibited by 5-HMF on alcohol-induced liver oxidative injury may be due to its potent antioxidant properties.

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.

: Perillae Fructus (PF) ( (L.) Britt.) and stir-fried Perillae Fructus (SFPF) are commonly used clinically for the treatment of cough and asthma, yet their quality control methods have not been fully established. : The best processing techniques of PF were optimized by one-variable-at-a-time (OVAT) analysis and Box-Behnken design (BBD); fingerprint combined with chemical pattern recognition techniques was employed to establish chromatographic fingerprints of PF and SFPF from different regions. Differential compounds were screened and the reliability of the established method was verified through quantitative analysis of multi-components; image processing technology was applied to determine chromaticity values and perform cluster heatmap analysis. The composition-color correlation of PF and SFPF was investigated. : Four characteristic components were identified through 36 batches of PF and SFPF, with rosmarinic acid, 5-hydroxymethylfurfural, caffeic acid and luteolin serving as discriminant markers differentiating PF and SFPF. The contents of seven components and the corresponding chromaticity parameters ( *, *, *) were determined to generate a visualized heatmap. Rosmarinic acid and caffeic acid showed positive correlations with *, whereas a negative correlation was shown with * and 5-hydroxymethylfurfural. : This study provides a theoretical basis for judgment of processing endpoints and the rapid online quality monitoring of SFPF.