Search

Honeydew honey is less studied than nectar honey, although it is characterized by peculiar nutritional properties. This is mainly due to its challenging production, which leads to easy counterfeiting and difficult valorization. This contribution aims to provide a comprehensive characterization of the physico-chemical, palynological, functional, and food safety properties of a large sampling of honeydew honeys collected throughout Italy. The honeydew elements, conductivity, color, antioxidant properties, total polyphenol content, hydroxymethylfurfural, major and trace elements, toxic and rare earth elements, and pesticide residues were measured in 59 samples of honeydew honey from forest, eucalyptus, fir, oak, and citrus sources. Physico-chemical and antioxidant properties were unable to differentiate the botanical origin of Italian honeydew honeys. Similarly, the mineral composition did not vary significantly, whereas rare earth elements appeared to be promising markers for classifying their origin. Multivariate analysis allowed discriminating fir honeydews from the other varieties. Concerning safety aspects, pesticide residues were detected in 90% of the samples, with fir honeydews exhibiting the lowest contamination levels, probably due to its production in less industrialized areas. Acetamiprid and imidacloprid were the most prevalent pesticide residues, but their concentrations were below the limit indicated by the EFSA. These findings suggest the need for a continuous monitoring program for contaminants to ensure safety and to assess risk. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate and compare some of the main indicators characterizing Bulgarian linden honey depending on the geographical origin. A total of 18 samples were collected from the six regions of Bulgaria, with 3 samples from each region taken from different producers during the 2023 harvest. The physicochemical indicators: hydroxymethylfurfural content, diastase activity, pH, color, water content and electrical conductivity, as well as organoleptic and pollen characteristics, were analyzed. Antioxidant activity was also investigated by several methods: total phenolic content (TPC), phenolic compounds by the Glories method, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical activity, CUPRAC (Cupric Reducing Antioxidant Capacity), iron-reducing antioxidant capacity (FRAP) assay, and radical scavenging capacity in terms of ABTS•+, ORAC (oxygen radical antioxidant capacity). Differences were found depending on the region. All the studied honeys from the Northern Central Region contained higher Tilia sp. pollen. In the Southwestern Region, Tilia sp. pollen was not detected in any of the honey samples. The highest sensory score was awarded to linden honey from the Northern Central Region. An overall assessment ranks linden honey from the Northern Central region, the richest in linden forests, as the highest quality among the six studied regions. Another key finding was that 39% of linden honey labeled or declared as monofloral linden honey on the Bulgarian market does not meet the established criteria for monofloral honey. [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]

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]

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 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]

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 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]

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]

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]

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]

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

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

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

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

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

Most of the foods we eat undergo a cooking process before they are eaten. During such a process, the non-enzymatic browning occurs, which generates compounds such as furosine, 5-hydroxymethylfurfural (HMF) and furfural. These are considered markers of cookedness and can therefore be used as quality indicators. In this work, we study the production of these compounds in different foods (both of plant and animal origin) that are cooked with different techniques. Additionally, we investigate correlations between the production of these markers of cookedness and the antioxidant capacity produced after in vitro digestion and fermentation. We observe that, in general, cereals and vegetables are more thermally damaged. Toasting and frying produce the highest concentrations of Maillard compounds whereas boiling the lowest. Furosine content shows a significant positive correlation with in vitro digestion data in fried foods, and with fermentation in roasted foods. Furfural content shows a significant positive correlation with in vitro digestion results in roasted foods, specifically in the Folin–Ciocalteu method. [ABSTRACT FROM AUTHOR]

The ingredients and the preparation methods influence biscuit quality and safety. In Iraq, biscuit imports are increasing every year, but no information is available in the scientific literature on their quality and safety features. This work analyzed three types of biscuits (cookies, crackers, and digestives) sampled in the Basrah markets (Iraq) but produced in Spain, Iran, Turkey, and United Arab Emirates. Nine different brands were considered for each country of origin (n = 36), with three replicates per sample. Moisture, ash, fat, proteins, fiber, water activity, peroxide value, 5-hydroxymethyl-2-furfural (HMF), acrylamide, heavy metals, and microbial load were analyzed. All the nutritional parameters were significantly influenced by the variables "Biscuit type" and "Country". Cookies showed significantly higher fat content and lower protein content than crackers and digestives, as well as higher peroxide value (which was below the limit set by the FAO/WHO within the World Wood Program). Spanish samples had more fat and fewer proteins than biscuits made in other countries. Very high variability was observed in HMF (from not detected to 62.08 mg/kg) and AA content (reaching 1421.8 μg/kg). Cadmium was always absent, and lead was considerably below the allowed limit. Yeasts and molds were above the limits in five samples. [ABSTRACT FROM AUTHOR]

Honey is known for its content of biomolecules, such as enzymes. The enzymes of honey originate from bees, plant nectars, secretions or excretions of plant-sucking insects, or from microorganisms such as yeasts. Honey can be characterized by enzyme-catalyzed and non-enzymatic reactions. Notable examples of enzyme-catalyzed reactions are the production of hydrogen peroxide through glucose oxidase activity and the conversion of hydrogen peroxide to water and oxygen by catalase enzymes. Production of hydroxymethylfurfural (HMF) from glucose or fructose is an example of non-enzymatic reactions in honey. [ABSTRACT FROM AUTHOR]

Noble metal-free catalysts based on earth-abundant and inexpensive mixed oxides are active catalysts of all steps of the reaction cascade leading from 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) using tert-butyl hydroperoxide (TBHP) as oxidation agent. Catalysts covering the whole range of composition in the Cu-Mn and Co-Fe series have been prepared and characterised. The nature and composition of the catalyst strongly affect conversion and selectivity. The distribution of products indicates that radical-type oxygen species, deriving from the activation of TBHP, play a determining role in the reaction. The early steps of reaction mainly follow the pattern expected for heterogeneous Fenton catalysts. Mixed oxide catalysts are the most effective in further oxidation steps, leading to the formation of FDCA, both in the Cu-Mn and Co-Fe systems. This behaviour can be related to the distribution of charge in the mixed oxides, suggesting a possible implication of the lattice oxygen in the last reaction steps. The results provide indications on how to optimize the reaction and minimize the formation of byproducts (humins and oligomers). [ABSTRACT FROM AUTHOR]

Three different types of biomass sourced from forestry waste (eucalyptus residues), agricultural waste (wheat straw), and energy crop (miscanthus) were used as starting materials to produce hemicellulosic sugars, furans (furfural and hydroxymethylfurfural), and oligosaccharides. A two-step hybrid process was implemented; biomass was first autohydrolysed without any additive to extract hemicelluloses and dissolve it in water. Then, the hydrolysate was treated with a solid acid catalyst, TiO2-WOx, in order to achieve hydrolysis and produce monomeric sugars and furans. This article investigates the role of the biomass type, autohydrolysis experimental conditions, polymerisation degree and composition of hemicelluloses on the performance of the process coupling autohydrolysis and catalytic hydrolysis. The highest global yields of both oligosaccharides and monomeric sugars were obtained from Eucalyptus (37% and 18%, respectively). [ABSTRACT FROM AUTHOR]

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

Fungal endophytes are an emerging source of novel traits and biomolecules suitable for lignocellulosic biomass treatment. This work documents the toxicity tolerance of Colletotrichum sp. OH toward various lignocellulosic pre treatment-derived inhibitors. The effects of aldehydes (vanillin, p-hydroxybenzaldehyde, furfural, 5-hydroxymethylfurfural; HMF), acids (gallic, formic, levulinic, and p-hydroxybenzoic acid), phenolics (hydroquinone, p-coumaric acid), and two pre treatment chemicals (hydrogen peroxide and ionic liquid), on the mycelium growth, biomass accumulation, and lignocellulolytic enzyme activities, were tested. The reported Colletotrichum sp. OH was naturally tolerant to high concentrations of single inhibitors like HMF (IC50; 17.5 mM), levulinic acid (IC50; 29.7 mM), hydroquinone (IC50; 10.76 mM), and H2O2 (IC50; 50 mM). The lignocellulolytic enzymes displayed a wide range of single and mixed inhibitor tolerance profiles. The enzymes β-glucosidase and endoglucanase showed H2O2 - and HMF-dependent activity enhancements. The enzyme β-glucosidase activity was 34% higher in 75 mM and retained 20% activity in 125 mM H2O2 . Further, β-glucosidase activity increased to 24 and 32% in the presence of 17.76 and 8.8 mM HMF. This research suggests that the Colletotrichum sp. OH, or its enzymes, can be used to pre treatment plant biomass, hydrolyze it, and remove inhibitory by-products. [ABSTRACT FROM AUTHOR]

Citrus fruits are rich sources of different phytochemicals for human health due to their high anti-oxidant capacity. However, the anti-aging effect of citrus fruits has not been well understood. In this study, methanol extracts taken at various developmental stages from tissues of Citrus unshiu was used to investigate its anti-aging effect by an elastase/collagenase inhibition assay, and a gas chromatography-mass spectrometry (GC-MS) analysis was carried out to identify the potential anti-aging compositions. The elastase/collagenase inhibitory activity was greatest in the flesh of immature green fruit (i.e., early July flesh (EJF)), and four candidate compounds were selected by GC-MS and evaluated by a collagenase inhibition assay. Three of the four candidate compounds (heptadecanoic acid, D-allose, and 5-hydroxymethyl-2-furaldehyde (HMF)) showed anti-aging activity, and the activity was highest in heptadecanoic acid, followed by D-allose and HMF. The total phenolic content (TPC), total flavonoid content (TFC), and anti-oxidant activity (DPPH and ferric reducing anti-oxidant power (FRAP) assay) were also investigated. Interestingly, the patterns of the total phenolic/flavonoid content and the anti-oxidant activity were different from that of the elastase/collagenase inhibitory activity. Flowers had the most anti-oxidant activity followed by immature fruit, and the fruit peels had more anti-oxidant activity than its flesh at all stages of development. This study demonstrated that the flesh of immature fruit and flowers of C. unshiu could be sources of anti-aging and anti-oxidant agents for human health, respectively. [ABSTRACT FROM AUTHOR]

Tumor microenvironments expose cancer cells to heterogeneous, dynamic environments by shifting availability of nutrients, growth factors, and metabolites. Cells integrate various inputs to generate cellular memory that determines trajectories of subsequent phenotypes. Here we report that short-term exposure of triple-negative breast cancer cells to growth factors or targeted inhibitors regulates subsequent tumor initiation. Using breast cancer cells with different driver mutations, we conditioned cells lines with various stimuli for 4 hours before implanting these cells as tumor xenografts and quantifying tumor progression by means of bioluminescence imaging. In the orthotopic model, conditioning a low number of cancer cells with fetal bovine serum led to enhancement of tumor-initiating potential, tumor volume, and liver metastases. Epidermal growth factor and the mTORC1 inhibitor ridaforolimus produced similar but relatively reduced effects on tumorigenic potential. These data show that a short-term stimulus increases tumorigenic phenotypes based on cellular memory. Conditioning regimens failed to alter proliferation or adhesion of cancer cells in vitro or kinase signaling through Akt and ERK measured by multiphoton microscopy in vivo, suggesting that other mechanisms enhanced tumorigenesis. Given the dynamic nature of the tumor environment and time-varying concentrations of small-molecule drugs, this work highlights how variable conditions in tumor environments shape tumor formation, metastasis, and response to therapy. [ABSTRACT FROM AUTHOR]

Hydroxymethylfurfural (HMF) has an outstanding position among bio-based platform chemicals, because high-value polymer precursors and fuel additives can be derived from HMF. Unfortunately, the large-scale industrial production of HMF is not yet realized. An open research question is the choice of hexose feedstock material. In this study, we used the highly available disaccharide sucrose for HMF synthesis. The conversion of sucrose was catalyzed by sulfuric acid in water media. Experiments were conducted at temperatures of 180, 200, and 220 °C with reaction times of 2-24 min. A carbon balance showed that the yield of unwanted side products rose strongly with temperature. We also developed a kinetic model for the conversion of sucrose, involving nine first-order reactions, to uncover the kinetics of the main reaction pathways. Within this model, HMF is produced exclusively via the dehydration of fructose. Glucose isomerizes slowly to fructose. Side products arise simultaneously from glucose, fructose, and HMF. A pathway from hexoses to xylose via reverse aldol reaction was also included in the model. We believe that sucrose is the ideal feedstock for large-scale production of HMF because it is more abundant than fructose, and easier to process than sugars obtained from lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

Enzymatic oxidation of 5-hydroxymethylfurfural (HMF) and its oxidized derivatives was studied using three fungal enzymes: wild-type aryl alcohol oxidase (AAO) from three fungal species, wild-type peroxygenase from Agrocybe aegerita (AaeUPO), and recombinant galactose oxidase (GAO). The effect of pH on different reaction steps was evaluated and apparent kinetic data (Michaelis-Menten constants, turnover numbers, specific constants) were calculated for different enzyme-substrate ratios and enzyme combinations. Finally, the target product, 2,5-furandicarboxylic acid (FDCA), was prepared in a multi-enzyme cascade reaction combining three fungal oxidoreductases at micro-scale. Furthermore, an oxidase-like reaction is proposed for heme-containing peroxidases, such as UPO, horseradish peroxidase, or catalase, causing the conversion of 5-formyl-2-furancarboxylic acid into FDCA in the absence of exogenous hydrogen peroxide. [ABSTRACT FROM AUTHOR]

We previously reported that the subcutaneous administration of 3,5,6,7,8,30,40- heptamethoxyflavone (HMF), a citrus polymethoxyflavone, attenuated depressive-like behavior and increased the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus of a corticosterone-induced depression-like mouse model. We herein demonstrated that (1) HMF was detectable in the brain 10 and 30 min after its oral administration, (2) orally administered HMF improved chronic unpredictable mild stress (CUMS)-induced pathological conditions, including body weight loss and depressive-like behavior, and CUMS-induced neurochemical changes, such as reduction in BDNF expression, decrease in neurogenesis, and decreased level of phosphorylated calcium-calmodulin-dependent protein kinase II in the hippocampus, and (3) these effects of HMF were inhibited by the pre-administration of U0126, a mitogen-activated protein (MAP) kinase inhibitor. These results suggest that orally administered HMF is beneficial for the upregulation of BDNF in the hippocampus via the extracellular signal-regulated kinase1/2 (ERK1/2)/MAP system, which may account for its antidepression effects. [ABSTRACT FROM AUTHOR]

This work deals with the development of a green and versatile synthesis of stable mono- and bi-metallic colloids by means of microwave heating and exploiting ecofriendly reagents: water as the solvent, glucose as a mild and non-toxic reducer and polyvinylpirrolidone (PVP) as the chelating agent. Particle size-control, total reaction yield and long-term stability of colloids were achieved with this method of preparation. All of the materials were tested as effective catalysts in the reduction of p-nitrophenol in the presence of NaBH4 as the probe reaction. A synergistic positive effect of the bimetallic phase was assessed for Au/Cu and Pd/Au alloy nanoparticles, the latter showing the highest catalytic performance. Moreover, monoand bi-metallic colloids were used to prepare TiO2- and CeO2-supported catalysts for the liquid phase oxidation of 5-hydroxymethylfufural (HMF) to 2,5-furandicarboxylic acid (FDCA). The use of Au/Cu and Au/Pd bimetallic catalysts led to an increase in FDCA selectivity. Finally, preformed Pd/Cu nanoparticles were incorporated into the structure of MCM-41-silica. The resulting Pd/Cu MCM-41 catalysts were tested in the hydrodechlorination of CF3OCFClCF2Cl to CF3OCF=CF2. The effect of Cu on the hydrogenating properties of Pd was demonstrated. [ABSTRACT FROM AUTHOR]

A series of Lewis acidic metal salts were used for glucose dehydration to 5-hydroymethylfurfural (HMF) in water. Effect of valence state, ionic radii of Lewis acidic cation, and the type of anions on the catalytic performance have been studied systematically. The experimental results showed that the valence state played an important role in determining catalytic activity and selectivity. It was found that a higher glucose conversion rate and HMF selectivity could be obtained over high valent Lewis acid salts, where the ionic radii of these Lewis acidic metal salts are usually relatively small. Analysis on the effect of the anions of Lewis acid salts on the catalytic activity and the selectivity suggested that a higher glucose conversion and HMF selectivity could be readily obtained with Cl-. Furthermore, the recyclability of high valence state Lewis acid salt was also studied, however, inferior catalytic performance was observed. The deactivation mechanism was speculated to be the fact that high valence state Lewis acid salt was comparatively easier to undergo hydrolysis to yield complicated metal aqua ions with less catalytic activity. The Lewis acidic activity could be recovered by introducing a stoichiometric amount of hydrochloric acid (HCl) to the catalytic before the reaction. [ABSTRACT FROM AUTHOR]

Inulin, a plant polysaccharide consisting of mainly D-fructose units, is considered an interesting feed for 5-hydroxymethylfurfural (HMF), a top 12 bio-based chemical. We here report an exploratory experimental study on the use of a wide range of homogeneous metal salts as catalysts for the conversion of inulin to HMF in water. Best results were obtained using CuCl2. Activity-pH relations indicate that the catalyst activity of CuCl2 is likely related to Lewis acidity and not to Brönsted acidity. The effects of process conditions on HMF yield for CuCl2 were systematically investigated and quantified using a central composite design (160-180 °C, an inulin loading between 0.05 and 0.15 g/mL, CuCl2 concentration in range of 0.005-0.015 M, and a reaction time between 10 and 120 min). The highest experimental HMF yield in the process window was 30.3 wt. % (39 mol %, 180 °C, 0.05 g/mL inulin, 0.005 M CuCl2 and a reaction time of 10 min). The HMF yields were modelled using non-linear, multi variable regression and good agreement between experimental data and model were obtained. [ABSTRACT FROM AUTHOR]

A family of tungstated zirconia solid acid catalysts were synthesised via wet impregnation and subsequent thermochemical processing for the transformation of glucose to 5-hydroxymethylfurfural (HMF). Acid strength increased with tungsten loading and calcination temperature, associated with stabilisation of tetragonal zirconia. High tungsten dispersions of between 2 and 7 W atoms·nm-2 were obtained in all cases, equating to sub-monolayer coverages. Glucose isomerisation and subsequent dehydration via fructose to HMF increased with W loading and calcination temperature up to 600 °C, indicating that glucose conversion to fructose was favoured over weak Lewis acid and/or base sites associated with the zirconia support, while fructose dehydration and HMF formation was favoured over Brönsted acidic WOx clusters. Aqueous phase reforming of steam exploded rice straw hydrolysate and condensate was explored heterogeneously for the first time over a 10 wt% WZ catalyst, resulting in excellent HMF yields as high as 15% under mild reaction conditions. [ABSTRACT FROM AUTHOR]

A new compound was detected during the production of 5-hydroxymethylfurfural (HMF) from glucose and cellulose in the ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) at high temperatures. Further experiments found that it was derived from the reaction of HMF with [Bmim]Cl. The structure of new compound was established as 1-butyl-2-(5′-methyl-2′-furoyl)imidazole (BMI) based on nuclear magnetic resonance and mass spectrometry analysis, and a possible mechanism for its formation was proposed. Reactions of HMF with other imidazolium-based ionic liquids were performed to check the formation of BMI. Our results provided new insights in terms of side reactions between HMF and imidazolium-based ionic liquids, which should be valuable for designing better processes for the production of furans using biomass and related materials. [ABSTRACT FROM AUTHOR]

The current trend of lowering 5-hydroxymethylfurfural (5-HMF) dietary exposure is challenging since its formation is parallel with the development of food color, flavor and aroma. We aimed to investigate the effect of gallic acid (GA) addition on 5-HMF formation, color development and antioxidant activity (AA) in a series of Maillard Reaction (MR) model systems. The effects of GA addition on browning and AA development were not uniform for all model systems, but always occurred in the same direction, indicating that these phenomena were interconnected. GA mitigated 5-HMF development in four of the nine tested systems, possibly by preventing the oxidation of MR intermediates. Correlation analysis indicated that when GA addition mitigated 5-HMF formation, browning was either promoted or not affected. The proposed strategy was effective for glucose/arginine and sucrose/arginine systems, since GA mitigated 5-HMF formation (49% and 54%, respectively) in addition to increasing color development and antioxidant activity. [ABSTRACT FROM AUTHOR]

In this study we aimed to investigate the effect of heat treatment on the spectral pattern of honey using near infrared spectroscopy (NIRS). For the research, sunflower, bastard indigo, and acacia honeys were collected from entrusted beekeepers. The honeys were not subject to any treatment before. Samples were treated at 40 °C, 60 °C, 80 °C, and 100 °C for 60, 120, 180, and 240 min. This resulted in 17 levels, including the untreated control samples. The 5-hydroxymethylfurfural (HMF) content of the honeys was determined using the Winkler method. NIRS spectra were recorded using a handheld instrument. Data analysis was performed using ANOVA for the HMF content and multivariate analysis for the NIRS data. For the latter, PCA, PCA-LDA, and PLSR models were built (using the 1300–1600 nm spectral range) and the wavelengths presenting the greatest change induced by the perturbations of temperature and time intervals were collected systematically, based on the difference spectra and the weights of the models. The most contributing wavelengths were used to visualize the spectral pattern changes on the aquagrams in the specific water matrix coordinates. Our results showed that the heat treatment highly contributed to the formation of free or less bonded water, however, the changes in the spectral pattern highly depended on the crystallization phase and the honey type. [ABSTRACT FROM AUTHOR]

The establishment of lignocellulosic biorefineries is dependent on microorganisms being able to cope with the stressful conditions resulting from the release of inhibitory compounds during biomass processing. The yeast Kluyveromyces marxianus has been explored as an alternative microbial factory due to its thermotolerance and ability to natively metabolize xylose. The lignocellulose-derived inhibitors furfural and 5-hydroxymethylfurfural (HMF) are considered promising building-block platforms that can be converted into a wide variety of high-value derivatives. Here, several K. marxianus strains, isolated from cocoa fermentation, were evaluated for xylose consumption and tolerance towards acetic acid, furfural, and HMF. The potential of this yeast to reduce furfural and HMF at high inhibitory loads was disclosed and characterized. Our results associated HMF reduction with NADPH while furfural-reducing activity was higher with NADH. In addition, furans' inhibitory effect was higher when combined with xylose consumption. The furan derivatives produced by K. marxianus in different conditions were identified. Furthermore, one selected isolate was efficiently used as a whole-cell biocatalyst to convert furfural and HMF into their derivatives, furfuryl alcohol and 2,5-bis(hydroxymethyl)furan (BHMF), with high yields and productivities. These results validate K. marxianus as a promising microbial platform in lignocellulosic biorefineries. [ABSTRACT FROM AUTHOR]

The table olive industry is producing a huge amount of wastewater, which is a post-processing cost and an environmental concern. The present study aims to valorize this processing by-product to obtain a value-added product, thereby enhancing resource efficiency and contributing to achieving sustainable development goals (SDGs). In this sense, a chemical reaction-based platform was developed to obtain valuable components, such as levulinic acid (LA) and 5-hydromethylfurfural (HMF). The products were then analyzed using NMR identification of the antioxidant phenolic fraction and microwave single-phase reaction of the sugary fraction. According to the results, the highest concentration of phenolic compounds does not correspond to the sample directly obtained from NaOH treatment (S1), indicating that water washing steps (S2–S5) are fundamental to recover phenolic substances. Moreover, glucose was presented in the sugary fraction that can be transformed into levulinic acid by a single-phase reaction under microwave irradiation. The information provided in this manuscript suggests that the wastewater from the olive processing industry can be valorized to obtain valuable products. [ABSTRACT FROM AUTHOR]

Lignocellulose and starch-based raw materials are often applied in the investigations regarding biohydrogen generation using dark fermentation. Management of the arising post-fermentation broth becomes a problem. The Authors proposed sequential processes, to improve the efficiency of both hydrogen generation and by-products management carried under model conditions. During the proposed procedure, the simple sugars remaining in broth are converted into organic acids, and when these products are used as substrates for the photo fermentation process. To enhance the broth management also conditions promoting Deep Eutectic Solvents (DES) precursors synthesis are simultaneously applied. Application of Box-Behnken design allows defining of the optimal conditions for conversion to DESs precursors. During the procedure hydrogen was obtained, the concentration of hydrogen in the photo fermentation reached up to 819 mL H2/L medium/7 d, depending on the broth type, i.e., when the broth was optimized for formic acid concentration. The DESs precursors were separated and engaged in DESs synthesis. To confirm the formation of the DESs, FT-IR analyses were performed. The Chemical Oxygen Demand of post-fermentation broths after dark fermentation optimized for formic acid was reduced by ca. 82%. The proposed procedure can be successfully used as a method of post-fermentation broth management. [ABSTRACT FROM AUTHOR]

This work aims to systematically investigate the influence of process temperature, biomass-to-water ratio, and production scales (laboratory and pilot) on the chemical composition of aqueous and gaseous phases and mass production of chemicals by hydrothermal processing of Açaí (Euterpe oleraceae, Mart.) seeds. The hydrothermal carbonization was carried out at 175, 200, 225, and 250 °C at 2 °C/min and a biomass-to-water ratio of 1:10; at 250 °C at 2 °C/min and biomass-to-water ratios of 1:10, 1:15, and 1:20 in technical scale; and at 200, 225, and 250 °C at 2 °C/min and a biomass-to-water ratio of 1:10 in laboratory scale. The elemental composition (C, H, N, S) in the solid phase was determined to compute the HHV. The chemical composition of the aqueous phase was determined by GC and HPLC and the volumetric composition of the gaseous phase using an infrared gas analyzer. For the experiments in the pilot test scale with a constant biomass-to-water ratio of 1:10, the yields of solid, liquid, and gaseous phases varied between 53.39 and 37.01% (wt.), 46.61 and 59.19% (wt.), and 0.00 and 3.80% (wt.), respectively. The yield of solids shows a smooth exponential decay with temperature, while that of liquid and gaseous phases showed a smooth growth. By varying the biomass-to-water ratios, the yields of solid, liquid, and gaseous reaction products varied between 53.39 and 32.09% (wt.), 46.61 and 67.28% (wt.), and 0.00 and 0.634% (wt.), respectively. The yield of solids decreased exponentially with increasing water-to-biomass ratio, and that of the liquid phase increased in a sigmoid fashion. For a constant biomass-to-water ratio, the concentrations of furfural and HMF decreased drastically with increasing temperature, reaching a minimum at 250 °C, while that of phenols increased. In addition, the concentrations of CH3COOH and total carboxylic acids increased, reaching a maximum concentration at 250 °C. For constant process temperature, the concentrations of aromatics varied smoothly with temperature. The concentrations of furfural, HMF, and catechol decreased with temperature, while that of phenols increased. The concentrations of CH3COOH and total carboxylic acids decreased exponentially with temperature. Finally, for the experiments with varying water-to-biomass ratios, the productions of chemicals (furfural, HMF, phenols, cathecol, and acetic acid) in the aqueous phase is highly dependent on the biomass-to-water ratio. For the experiments at the laboratory scale with a constant biomass-to-water ratio of 1:10, the yields of solids ranged between 55.9 and 51.1% (wt.), showing not only a linear decay with temperature but also a lower degradation grade. The chemical composition of main organic compounds (furfural, HMF, phenols, catechol, and acetic acid) dissolved in the aqueous phase in laboratory-scale study showed the same behavior as those obtained in the pilot-scale study. [ABSTRACT FROM AUTHOR]

Chokeberry fruit, one of the richest plant sources of bioactives, is processed into different foodstuffs, mainly juice, which generates a considerable amount of by-products. To follow the latest trends in the food industry considering waste management, the study aimed to produce chokeberry pomace extract powders and conduct experimental and chemometric assessment of the effect of different carriers and drying techniques on the physico-chemical properties of such products. The PCA analysis showed that the examined powders were classified into two groups: freeze-dried (variation in case of moisture content, water activity, colour, and browning index) and vacuum-dried (bulk density). No clear pattern was observed for the physical properties of carrier added products. The sum of polyphenolics (phenolic acids, anthocyanins and flavonols) ranged from 3.3–22.7 g/100 g dry matter. Drying techniques had a stronger effect on the polyphenols profile than the type of carrier. Hydroxymethyl-L-furfural formation was enhanced by inulin addition during high-temperature treatment. Overall, the addition of maltodextrin and trehalose mixture for freeze drying and vacuum drying at 90 °C caused the highest retention of polyphenolics and the lowest formation of hydroxymethyl-L-furfural; however, an individual and comprehensive approach is required when the obtainment of high-quality chokeberry powders is expected. [ABSTRACT FROM AUTHOR]

5-(hydroxymethyl)furan-2-carbaldehyde, better known as hydroxymethylfurfural (HMF), is a well-known freshness parameter of honey: although mostly absent in fresh samples, its concentration tends to increase naturally with aging. However, high quantities of HMF are also found in fresh but adulterated samples or honey subjected to thermal or photochemical stresses. In addition, HMF deserves further consideration due to its potential toxic effects on human health. The processes at the origin of HMF formation in honey and in other foods, containing saccharides and proteins—mainly non-enzymatic browning reactions—can also produce other furanic compounds. Among others, 2-furaldehyde (2F) and 2-furoic acid (2FA) are the most abundant in honey, but also their isomers (i.e., 3-furaldehyde, 3F, and 3-furoic acid, 3FA) have been found in it, although in small quantities. A preliminary characterization of HMF, 2F, 2FA, 3F, and 3FA by cyclic voltammetry (CV) led to hypothesizing the possibility of a comprehensive quantitative determination of all these compounds using a simple and accurate square wave voltammetry (SWV) method. Therefore, a new parameter able to provide indications on quality of honey, named "Furanic Index" (FI), was proposed in this contribution, which is based on the simultaneous reduction of all analytes on an Hg electrode to ca. −1.50 V vs. Saturated Calomel Electrode (SCE). The proposed method, validated, and tested on 10 samples of honeys of different botanical origin and age, is fast and accurate, and, in the case of strawberry tree honey (Arbutus unedo), it highlighted the contribution to the FI of the homogentisic acid (HA), i.e., the chemical marker of the floral origin of this honey, which was quantitatively reduced in the working conditions. Excellent agreement between the SWV and Reverse-Phase High-Performance Liquid Chromatography (RP-HPLC) data was observed in all samples considered. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass, a cheap and plentiful resource, could play a key role in the production of sustainable chemicals. The simple sugars contained in the renewable lignocellulosic biomass can be converted into commercially valuable products such as 5-hydroxymethyl furfural (HMF). A platform molecule, HMF can be transformed into numerous chemical products with potential applications in a wide variety of industries. Of the hexoses contained in the lignocellulosic biomass, the successful production of HMF from glucose has been a challenge. Various heterogeneous catalysts have been proposed over the last decade, ranging from zeolites to metal organic frameworks. The reaction conditions vary in the reports in the literature, which makes it difficult to compare catalysts reported in different studies. In addition, the slight variations in the synthesis of the same material in different laboratories may affect the activity results, because the selectivity towards desired products in this transformation strongly depends on the nature of the active sites. This poses another difficulty for the comparison of different reports. Furthermore, over the last decade the new catalytic systems proposed have increased profoundly. In this article, we summarize the heterogeneous catalysts: Metal Organic Frameworks (MOFs), zeolites and conventional supported catalysts, that have been reported in the recent literature and provide an overview of the observed catalytic activity, in order to provide a comparison. [ABSTRACT FROM AUTHOR]