Furfural Compounds Research Articles

Effects of saccharides on the contents of furfural compounds in modified milk

In Chinese dairy products, various saccharides including sugar substitutes are often added to modified milk or milk beverages to enhance flavor or increase benefits. That might result in the formation of furfural compounds due to the Maillard reaction between reducing sugars and proteins during heat treatment of milk. The contents of furfural compounds in dairy products vary depending on the type and proportion of sugars added, as well as the strength of heat treatment. Three monosaccharides, four disaccharides and two polysaccharides were selected to study the influences of saccharides on furfurals in modified milk. Kinetics parameters for the formation of furfural compounds were also studied under pilot processing conditions. The contents of furfurals in milk increased with the addition of monosaccharide, in the following order (from high to low) of type: fructose > galactose > glucose, and increased with the decrease in the polymerization degree of the added saccharides. The resulted prediction equations could be used to estimate the contents of furfurals in modified milk added with glucose, maltose or glucan after heat treatment at 115 °C–135 °C. This paper could provide a reference for the prediction and control of furfurals when applying saccharides in the dairy industry.

Investigation of the formation of furfural compounds in apple products treated with pasteurization and high pressure processing

The thermal treatment carried out in the processing of apple products is very likely to induce Maillard reaction to produce furfurals, which have raised toxicological concerns. This study aimed to elucidate the formation of furfural compounds in apple products treated with pasteurization and high pressure processing (HPP). The method for simultaneous determination of five furfural compounds including 5-hydroxymethyl-2-furfural (5-HMF), furfural (F), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), 2-acetylfuran (FMC), and 5-Methyl-2-furfural (MF) using high performance liquid chromatography equipped with diode array detector (HPLC-DAD) was successfully developed and validated. All five furfurals exhibited an increasing trend after the pasteurization treatment of apple clear juice, cloudy juice, and puree. 5-HMF, F, FMC, and MF were increased significantly during the precooking of apple puree. Whereas there was no significant change in the furfurals formation after apple products treated with high pressure processing (HPP) with 300 MPa and 15 min. Based on the variation of the fructose, glucose and sucrose detected in apple products after thermal treatment, it revealed that the saccharides and thermal treatment have great effect on the furfural compounds formation. The commercial fruit juice samples with different treatments and fruit puree samples treated with pasteurization were also analyzed. Five furfurals were detected more frequently in the fruit juice samples treated with pasteurization or ultra-high temperature instantaneous sterilization (UHT) than those treated with HPP. 5-HMF and FMC were detected in all fruit puree samples treated with pasteurization, followed by F, MF, and HDMF with the detection rate of 79.31 %, 72.41 %, and 51.72 %. The results could provide a reference for risk assessment of furfural compounds and dietary guidance of fruit products for human, especially for infants and young children. Moreover, moderate HPP treatment with 300 MPa and 15 min would be a worthwhile alternative processing technology in the fruit juice and puree production to reduce the formation of furfural compounds.

Thermotolerant acetic acid bacteria in the production of a red wine vinegar by surface culture at different temperatures: volatile and polyphenolic composition

This work aims to determine the effect on the aromatic profile and phenolic content of red wine vinegars produced by surface culture at two different temperatures (30 °C and 37 °C) and using different inocula of acetic acid bacteria (Acetobacter malorum, Gluconobacter oxydans and a mixture of bacteria isolated from a Sherry vinegar). Fifty-seven volatile compounds and 23 polyphenolic and furfural compounds were identified. Vinegars obtained at 37 °C had poorer volatile profiles, with no significant influence of the strain of acetic bacteria. For polyphenolic content, temperature was also the most significant variable, so that the vinegars produced at higher temperatures had lower total anthocyanin contents, while no clear trend was observed regarding the influence of temperature on the low-molecular-weight phenolic constituents. The total tannin content in the vinegars obtained experienced slight increases after acetification, although this was not affected by temperature, and it was observed that when using the mixture of acetic acid bacteria from the Sherry vinegar, the total tannin content was significantly higher than when individual bacteria cultures of Acetobacter malorum or Gluconobacter oxydans were used. Temperature appears as a key parameter for the volatile and phenolic composition of red wine vinegar versus the use of different acetic acid bacteria.

Determination of the Maillard reaction products in complementary rice, flour, and noodles by high performance liquid chromatography with a diode array detector

AbstractA method was established for the simultaneous determination of furosine, furanone, and four furfural compounds (5‐hydroxymethylfurfural, furfural, furyl methyl ketone, and methyl furfural) in complementary rice, flour, and noodles for infants and young children by high performance liquid chromatography with a diode array detector. The sample was extracted using oxalic acid aqueous solution as a solvent, and the protein was removed using trichloroacetic acid. Then the six Maillard reaction products were separated by an Eclipse XDB‐C18 column with a gradient elution at a flow rate of 0.6 mL/min using acetonitrile‐0.1% trifluoroacetic acid solution as the mobile phase, detected by a diode array detector and quantified by external standard method. The linear ranges of the six Maillard reaction products were 250–20000 μg/100 g with the correlation coefficients greater than 0.999, and the limits of quantification ranged from 250 to 1000 μg/100 g (S/N ≥ 10). The recoveries of the six Maillard reaction products ranged from 71.2% to 100% with a relative standard deviation of 0.9%–4.9%. The real sample analysis results showed that 5‐hydroxymethylfurfural was detected in two cookie samples, the contents of which were 335 μg/100 g and 436 μg/100 g, respectively. There are no studies on the detection of the six Maillard reaction products in rice, flour, and noodles in the previous reports. The established method provided reference for the quantification of expiration date in complementary rice, flour, and noodles for infants and young children.

DETERMINATION OF MAILLARD REACTION MARKERS IN DOCE DE LEITE BY HPLC-PDA

This study was carried out as a preliminary mapping of Maillard reaction (MR) compounds in doce de leite (DL), as possible indicators for the intermediate stage and chemical pathways in industrial processing. For that, the objective of the manuscript was to developed and validated an analytical method to simultaneously analyze four furfural compounds in DL: 5-hydroxymethylfurfural, 2-furaldehyde (F), 2-furyl-methyl ketone (FMC) and 5-methyl-2-furaldehyde (MF) by high performance liquid chromatography-photodiode-array detector (HPLC-PDA). The method fulfilled the acceptance criteria: selectivity, linearity (0.16-5 µg mL-1 for HMF, and 0.06-2 µg mL-1 for F, FMC and MF, R2 > 0.9974), precision (CV = 1.33 to 2.12% for HMF; 1.57 to 4.34% for F; 0.84 to 1.40% for FMC and 1.40 to 4.18% for MF), accuracy (94.40 to 102.25% for HMF; 92.91 to 108.15% for F; 90.13 to 108.48% for FMC and 93.31 to 107.70% for MF), limit of detection of 0.041 µg mL-1 for HMF; 0.030 µg mL-1 for F; 0.042 µg mL-1 for FMC and MF, and limit of quantification of 0.125 µg mL-1 for HMF and F, 0.066 µg mL-1 for FMC and 0.1280 µg mL-1 for MF. Thus, it was concluded that an analytical method was developed and validated for quantifying HMF, F, FMC and MF in DL.

Bi-ligand-fabricated CdS quantum dots to photo-induce aqueous-phase aldol condensation for biomass-derived carbonyl compounds.

CdS QDs were fabricated using bi-ligands 11-sulfanylundecanoic acid and proline for photo-induced aqueous-phase aldol condensation of biomass-derived furfural compounds and ketones, and they displayed acceptable selectivity, activity and recycling properties for generation of a wide range of products with diverse applications. This work facilitates understanding the molecular-level design concepts of semiconductor photocatalysts.

Unveiling bacterial consortium for xenobiotic biodegradation from Pichavaram mangrove forest soil: a metagenomic approach.

Pichavaram mangrove forest was established as a wetland of International Importance by Article 2.1 in April 2022 by the Ministry of Environment, Forest and Climate Change, India. Even though it is a conserved site, xenobiotic agrochemical leaching on the forest land during monsoon is inevitable. These threaten the microbial diversity in the environment. Xenobiotic degradation is achieved using bacterial consortia already acclimatised to this environment. This study aims to identify the indigenous microbial consortia able to degrade xenobiotic compounds such as fluorobenzoate, furfural, and steroids. Pichavaram mangrove metagenomic dataset was obtained by shotgun sequencing of soil DNA and processed using the automated tool SqueezeMeta. Further, the DIAMOND database provided the taxonomical classification of the microbes in each contig. With reference to the KEGG database, the selected xenobiotic degradation pathways were confirmed in the dataset. Of 1,253,029 total contigs, 1332, 72 and 1262 were involved in fluorobenzoate, furfural and steroid degradation, respectively. This study identified that microbial consortia comprising Marinobacter, Methyloceanibacter and Vibrio natriegens/Gramella sp. can degrade fluorobenzoate. While Afipia, Nitrosopumilus sp., and Phototrophicus methaneseepsis favour the degradation of furfural compound. The steroid degradation pathway possessed a plethora of bacteria belonging to the phylum Proteobacteria.

Rapid identification of high-temperature Daqu Baijiu with the same aroma type through the excitation emission matrix fluorescence of maillard reaction products

The flavor of high-temperature Daqu Baijiu with the same aroma type is similar but the quality and price are very different, so that the high-quality Baijiu is often pretended as low-quality Baijiu. In this study, excitation-emission matrix fluorescence spectrometry combined with chemometrics was proposed for rapid identification of high temperature Daqu Baijiu with the same aroma type. The method was based on seven components screened by alternating trilinear decomposition (ATLD), and the discriminant model was established by data-driven-soft independent modeling of class analogy (DD-SIMCA), with the discriminant rate of 100%. Some Maillard reaction products, such as pyrazine and furfural compounds, with correlation >0.8 were obtained by GC-MS combined with Pearson analysis, and the prediction accuracy between 90.32% and 96.77%. This method has the characteristics of high sensitivity, fast detection and no pre-treatment, which provides a new strategy for rapid discrimination of high-temperature Daqu Baijiu with the same aroma type.

Utilization of Bamboo Waste by Engineering Acid Hydrolysis (H2SO4) to Produce Furfural Compounds

Utilization of Bamboo Waste by Engineering Acid Hydrolysis (H2SO4) to Produce Furfural Compounds

Mechanism of sugar degradation product 5-hydroxymethylfurfural reducing the stability of anthocyanins.

The coexistence of anthocyanin with the sugar degradation product 5-hydroxymethylfurfural (5-HMF) is inevitable during the processing and storage of anthocyanin-rich juices. It was determined from our study that lower concentrations of 5-HMF have little effect on the stability of Cyanidin-3-O-glucoside (C3G), and even cause a slight increase for a short period of time. As the concentration of 5-HMF increased, the retention of C3G decreased and the color of the solution changed from orange-red to purple-red. The reaction sites of 5-HMF and C3G in its hemiketal form were predicted by quantum chemical calculations in order to investigate the pathways of action of the two. The degradation mechanism of 5-HMF on anthocyanin was verified by Ultraviolet and Visible spectrophotometer and Ultra performance liquid chromatography-mass spectrometry. Therefore, this article provides further theoretical support for the study of the effect of furfural compounds, which are sugar degradation products, on the stability of anthocyanins.

5-Hydroxymethylfurfural Ameliorates Allergic Inflammation in HMC-1 Cells by Inactivating NF-κB and MAPK Signaling Pathways.

Allergic inflammation is the foundation of multiple allergic disorders, such as allergic rhinitis and asthma. Mast cells are effector cells that initiate inflammatory response. 5-hydroxymethylfurfural (5-HMF), a furfural compound, is the heat-processed product of various fruit, foods, drinks, as well as some Chinese herbal medicines. 5-HMF was previously reported to inhibit mast cell activation. Our study aimed to explore the functions of 5-HMF in both phorbol 12-mystate 13-acetate (PMA) plus calcium ionophore (A23187)-induced allergic inflammation in human mast cell line HMC-1 and ovalbumin (OVA)-induced asthma mouse models. HMC-1 cells were pretreated with 5-HMF and then stimulated by PMA+A23187. The cytotoxicity of 5-HMF on HMC-1 cells was evaluated by MTT assay. Histamine content in cell supernatants was measured by the o-phthaldialdehyde spectrofluorometric procedure. Intracellular calcium was determined using the fluorescent dye Fura-2AM. The production and expression of pro-inflammatory cytokines were detected by ELISA and RT-qPCR. Caspase-1 colorimetric assay was employed to examine the enzymatic activity of caspase-1. Asthma mouse models were induced by OVA sensitization. The bronchoalveolar lavage fluid (BALF) and blood samples were collected for the detection of total and differential cell count as well as aspartate aminotransferase (AST), alanine aminotransferase (ALT), OVA-immunoglobulin E (OVA-IgE), OVA-immunoglobulin G1 (OVA-IgG1), and pro-inflammatory cytokine levels. The left lung of mouse was dissected for histopathological examination by hematoxylin and eosin (H&E) staining. The protein expression of pro-caspase-1 and the phosphorylation of NF-κB and MAPK pathway-associated molecules were assessed by Western blotting. Our findings revealed that 5-HMF efficiently suppressed the PMA+A23187-induced enhancement in histamine production and intracellular calcium in HMC-1 cells. Pro-inflammatory cytokine production and expression in HMC-1 cells were elevated after PMA plus A23187 stimulation, which, however, were inhibited by pretreatment of 5-HMF. Additionally, 5-HMF suppressed the activity of caspase-1 and the phosphorylation of NF-κB and MAPK-associatedmolecules including p65 NF-κB, p38 MAPK, ERK, and JNK in HMC-1 cells. In vivo experiments demonstrated that 5-HMF treatment reduced the lung/body weight index and total and differential (macrophages, neutrophils, lymphocytes, and eosinophils) cell counts in BALF of asthmatic mice, but exerted no influence on serum AST and ALT levels. Besides, 5-HMF reduced serum OVA-IgE and OVA-IgG1 levels, mitigated lung inflammation, and inhibited the NF-κB and MAPK signaling pathways in asthma mouse models. 5-HMF mitigates allergic inflammation in asthma by inactivating caspase-1 and NF-κB and MAPK signaling pathways.

Recent Advances in Metallic Catalyst Materials for Electrochemical Upgrading of Furfurals to Drop‐in Biofuels: A Mini Review

Electro‐organic synthesis is an ecologically benign and cost‐effective technique. Among other purposes, it can be used to produce a broad spectrum of biofuels for aviation applications. Metallic electrocatalyst materials employed for electro‐organic synthesis enable the conversion of biomass derived furfural compounds to various furanic biofuels. Each metallic catalyst material has its own inherent characteristics of generating specific amounts of fine chemicals and fuel components. By and large, furanic biofuels produced using metallic catalyst materials are favored explicitly under acidic or mildly acidic electrolytes. Therefore, it is intriguing to understand the nature of different catalyst materials that are compatible with acidic electrolytes. Herein, the focus will be on the recent progress in the field of electro‐organic synthesis of furanic fuels under acidic conditions. This review provides an overview of electrocatalytic conversion, its fundamentals, the reaction pathways observed during conversion, and the importance of metallic catalyst materials. Subsequently, the role of noble and nonnoble metallic catalysts on the electrocatalytic transformation of furfural compounds to various biofuels in acidic environment is discussed. In the end, perspectives are presented with regard to the challenges associated with the current technology and possible ways to look ahead to scale up the current technology.

Electrochemical reconstitution of Prussian blue analogue for coupling furfural electro-oxidation with photo-assisted hydrogen evolution reaction

Prussian blue (PB) and its analogues (PBAs) have served as effective electrocatalysts for the oxidation of biomass. However, the PBA-based catalyst is prone to structural changes in the electrochemical process under alkaline medium, which may alter the mechanism and kinetics of the electrocatalytic reaction. Herein, a PBA-based catalytic electrode (NiFe/Ni) is obtained by depositing Ni2[Fe(CN)6] on Ni foam through a wet chemistry method. It is found that Ni2[Fe(CN)6] converts to high-valence NiOOH during the electrochemical process in alkaline medium. Meanwhile, the polarons generated by lattice deformation in Ni2[Fe(CN)6] can transform into NiOOH with oxygen vacancies (v-NiOOH). The obtained v-NiOOH endows the catalytic electrode with superior performance for the electro-oxidation of furfural compounds to furoic acids. The in-situ ATR-FTIR and furfural temperature-programmed desorption further prove that the fast furfural electro-oxidation kinetics can be ascribed to the high-flux furfural adsorption ability of the v-NiOOH. In addition, the electrocatalytic oxidation of furfural and photo-assisted hydrogen evolution reaction are integrated into a water-splitting electrolyzer. Compared with the conventional water-splitting electrolyzer, the integrated electrolyzer can reduce the cell voltage by 480 mV at 100 mA cm−2. This work proves the electrochemical reconstitution of the PBA-based catalysts for biomass oxidation under alkaline electrolyte, which provides a new way for the design of PBA-based electrocatalysts.

A comparative study between some biocontrol agents and the nematicide furfural on growth of tomato plants and pathogenesis of meloidogyne javanica under green-house condition

An experiment was conducted to study the effect of three fungal biocontrol agents along with G.mosseae and nematicide furfural against root knot nematode Meloidogyne javanica infecting tomato plants(Lycopersicon esculentum) under greenhouse condition. Bioagents are Paecilomyces lilacinus, Trichoderma harzianum , T. viride and mycorrhizal fungus Glomus mosseae which were compared with the nematicide furfural . The furfural compound was the best treatment in promoting plant growth and reduction the number of root galls/plant . The result showed that the T. harzianum was the best biocontrol agent in increasing shoot length and root length 16.2 % , 26.1% respectively .The P. lilacinus was the best biocontrol agent in reduction root galling (57.53%). Combination of biocotrol agents with G. mosseae and furfural was the least effective treatment in promoting plant growth and the reduction of root galling was 31.43%.

The importance of constructing Triple-functional Sr2P2O7/Ni2P catalysts for smoothing hydrogenation Ring-rearrangement of Biomass-derived Furfural compounds in water

Rational design of catalysts with multi-function was of great importance for speeding mechanism-complicated heterogeneous reaction. Herein, a series of Sr-Ni-P catalysts characterized in (Sr2P2O7)m/Ni2P composite structure (Sr:Ni molar ratio m = 0.15–0.60) were prepared and investigated for hydrogenation ring-rearrangement of four biomass-derived Furfural compounds (FALs) to their Cyclopentanone derivatives (CPOs) in water. By properly manipulate m at 0.40, the superior and reproducible CPOs yields up to 96% were achieved under mild conditions in particular under low-pressure (0.1 MPa) H2. Chemical adsorption measurements disclosed that the attachment of Sr2P2O7 with Ni2P in nanoscale was crucial to construct triple-functional catalytic interface with modulated hydrogen activation (7.5–47.4 µmol/g), acid (196.4–327.3 µmol/g) and base (108.0–214.5 µmol/g) sites. H2-D2 exchange, H2-IR experiments and DFT simulation implied that H2 could be activated through heterolytic dissociation on Sr2P2O7 to participate in reaction; H218O, D2O, D2 isotope-label tracing experiments and DFT mechanism calculation further clarified that besides of H2, H2O was also frequently present in hydrogenation, ring opening, rearrangement and ring re-closing steps and acted as dual donors to provide H and O for CPO; in the favorable thermodynamic feature, a new pathway (with unsaturated dicarbonyl compound as key intermediate) achieved on Sr2P2O7/Ni2P was demonstrated to be more feasible than the reported pathway. The importance of the triple-functional Sr2P2O7/Ni2P catalytic interface for smoothing the aqueous hydrogenation transformation, in particular the function of base site for speeding the transformation was illustrated and discussed.

Determination of three furfural compounds in coffee and coffee products by gas chromatography-tandem mass spectrometry with internal standard isotope

To establish a method for the determination of three furfural compounds in coffee and its products by gas chromatography-tandem mass spectrometry. The samples were extracted with ethanol water(1∶2, V∶V) solution, ultrasonic with 10% Na_2CO_3 solution for 5 min, purified with 100 mg C_(18), 50 mg Srong Cation exchang(SCX), 150 mg anhydrous MgSO_4, separated by HP-INNOWAX capillary column(30 m×0.25 mm, 0.25 μm), detected by gas chromatography-tandem mass spectrometry, and quantified by isotope internal standard method. The correlation coefficients(r) of the three furfural compounds were all greater than 0.999, the limits of detection were 0.004-0.011 mg/kg, and the limits of quantitation were 0.013-0.031 mg/kg. The average recoveries were 86.0%-112% and the relative standard deviations were 4.1%-10.6%(n=6), at 3 supplemental levels in 3 different coffee substrates. Nine samples of coffee beans, instant coffee and coffee drinks were tested, and all three components to be tested were detected. The method is simple, rapid, sensitive, with good accuracy and precision. It is suitable for the determination of three furfural compounds in coffee and its products.

Effective hydrolysis for waste plant biomass impacts sustainable fuel and reduced air pollution generation: A comprehensive review

Among various natural biowastes availability in the environment, agricultural residues showed great impacts. It is due to huge availability and cheap carbon source, creating big challenges for their utility and systematic reduction. Objective of this review is to address the waste biomass availability and huge quantities issues and also put effort to minimize this nutrient load via biotransforming into value-added products. Different wastes (organic/inorganic) generation with their negative issues are due to numbers of developmental and social activities, reported. Currently, various efforts are found for these wastes minimization via generation of different types of value-added products (biogas, bioH2, alcoholic fuel, organic acids and others products) and these wastes in municipal cities are also reported with production of advanced biofuels as promising outcomes. For hydrolysis of complex organic resources including lignocellulosic biomasses, physicochemical, structural or compositional changes are needed that aid in conversion into sugar and organic compounds such as biofuels. So, efficient and effective pretreatment processes selection (physical, biological, chemical or combined one) is critical to achieve these hydrolysis goals and resultant cellulose or hemicellulose components can be accessible by biological catalysis. These can achieve final hydrolysis and fermentative or monomer sugars. And later, synthesis of fuels or value-added products during microbial fermentation or biotransformation processes can be achieved. This review discusses pretreatment techniques for improved hydrolysis for fermentative sugar with emphasis on reduced quantities of toxic compounds (furfural compound) in hydrolyzed biomasses. Minimum deterioration fuel economy also reported with production of different bioproducts including biofuels. Additionally, impacts of toxic products and gasses emission are also discussed with their minimization.

Expression of Furfural Reductase Improved Furfural Tolerance in Antarctic Bacterium Pseudomonas extremaustralis

Whole-cell biocatalysis using Antarctic bacteria is presently hampered by a lack of genetic information, limited gene tools and critically, a poor range of cultivation conditions. In this work, biological engineering strategy was employed for developing Pseudomonas extremaustralis, a metabolically-versatile and biopolymer-producing Antarctic bacterium, as a new whole-cell biocatalytic host. For this purpose, gene cloning and plasmid construction were carried out for overexpression of furfural reductase (FucO), an industrially-important enzyme for degradation of toxic furfural compound commonly found in lignocellulosic biorefinery. FucO gene from Escherichia coli BL21 was cloned in pJM105 plasmid and transformed into competent cells of P. extremaustralis to generate a biologically-engineered pFucO strain. For functional characterization of the enzyme, furfural reductase activity was assayed, where the P. extremaustralis pFucO strain exhibited increased furfural reductase activity of about 15.6 U/mg, an 18.8-fold higher than empty plasmid-carrying control pJM105 strain (0.83 U/mg). Furfural detoxification activity using whole cells was also determined by which the overexpression of FucO led to increased tolerance and cell growth with an OD600 value of 5.3 as compared to the control pJM105 strain that was inhibited with 10 mM furfural during 48-hour cultivation. Therefore, the findings obtained in this study successfully demonstrated the development of P. extremaustralis as biocatalytic host for the production of recombinant furfural reductase. The bioengineering would serve as a modular biotechnological platform for polar strain and bioproduct development tailored towards industrial biotechnology applications.

A monolith adsorbent of hyper-crosslinked polymer, graphene oxide composite chitosan cryogel for in-syringe solid phase extraction of furfural derivatives from cellulosic biomass hydrolysate

A porous composite monolith adsorbent of hyper-crosslinked polymer, graphene oxide and chitosan cryogel was fabricated for the extraction of furfural and 5-hydroxymethyl-furfural from cellulosic biomass hydrolysate. The composite adsorption materials synergistically enhanced the adsorption of furfural compounds and the porous chitosan cryogel helped to entrap and prevent the loss of the adsorbent composite. The composite monolith adsorbent was in-situ fabricated in a needle hub assembled with a disposable syringe performing in-syringe solid phase extraction. The extracted furfural compounds were quantified by high performance liquid chromatography. The fabricated adsorbent was characterized and the extraction conditions were optimized to achieve the best extraction recovery. In the optimum condition, the developed analytical approach provided linear from 1.0 to 50 ng/L for furfural and 0.5 to 50 ng/L for 5-hydroxymethyl-furfural, with respective detection limits of 0.25 ng/L and 0.20 ng/L. The developed approach was employed for the determination of furfural and 5-hydroxymethyl-furfural extracted from biomass hydrolysate of empty palm fruit bunch cellulose with satisfactory relative recoveries from 90.6 to 101.6 % with the RSDs below 6 %. The developed composite monolith adsorbent is easy to prepare and the extraction format is convenient to use. The good stability of the composite monolith adsorbent enabled reusability for 20 extraction-desorption cycles.

Maillard reaction products and amino acid cross-links in liquid infant formula: Effects of UHT treatment and storage

The formation of Maillard reaction products, including Amadori compounds (determined as furosine), advanced glycation end products (AGEs), α-dicarbonyl and furfural compounds, as well as amino acid cross-links (lysinoalanine and lanthionine) was investigated in direct (DI) and indirect (IN) UHT-treated experimental liquid infant formula (IF) during storage at 40 °C. IN-IF had higher concentrations of all investigated compounds compared to DI-IF and low pasteurized IF. IN UHT treatment induced significantly higher concentrations of α-dicarbonyl compounds (glyoxal, methylglyoxal, 3-deoxyglucosone and 3-deoxygalactosone) compared to DI, which facilitated increased formation of AGEs (N-Ɛ-(carboxymethyl)lysine, methylglyoxal- and glyoxal-derived hydroimidazolones) in unstored IFs. During storage for 6 months, concentrations of furosine and AGEs increased while α-dicarbonyl compounds decreased. Principal component analysis indicated that differences between IN-IF and DI-IF disappeared after 2 months of storage. IN-IF had higher concentrations of lysinoalanine and lanthionine and lower concentrations of available lysine and arginine than DI-IF indicating higher loss of protein quality in IN-IF.