• Korean Journal of Food Science and Technology
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• v.14 no.3
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• pp.265-270
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• 1982

An attempt was made to investigate the antioxidant activity of maltol, kojic acid, levulinic acid, furfural, 5-hydroxymethyl furfural (5-HMF), and pyrazine which had been known to be important intermediates of Maillard browning reactions. The activity of these compounds was determined by comparing induction periods of soybean oil substrates containing each compound at a 0.01M level with that of a control. The induction period was arbitrarily taken as the time in hours for a substrate to reach a peroxide value of 60meq/kg oil. The substrates and control were stored at $45.0{\pm}1.0^{\circ}C$ for 30 days. The induction periods of the control, kojic acid, furfural, 5-HMF, maltol, levulinic acid, and pyrazine were respectively 468, 592, 510, 498, 486, 450, and 402 hours. Kojic acid demonstrated considerable antioxidant activity, whereas furfural, 5-HMF, and maltol showed weak activivity. Pyrazine and levulinic acid showed pro-oxidant activity. Although the prooxidant activity of pyrazine seemed definite, that of levulinic acid appeared very weak.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.61-65
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• 2018

In this study, the conversion of glucosamine, which is a major monomer in chitin/chitosan of crustacean shell, using solid acid catalyst was performed to obtain chemical intermediates such as levulinic acid and 5-hydroxymethyl furfural (5-HMF). The conversion reaction was optimized with four reaction factors of selection of ionic resin catalyst, reaction temperature, catalyst amount, and reaction time. As an optimized result, the highest levulinic acid yield was achieved approximately 36.86% under the determined conditions (Amberlyst 15 as a solid-acid catalyst, $180^{\circ}C$, 5% catalyst amount and 60 min). On the other hand, 5-HMF yield was found to be 0.91% at the condition.

• Journal of the Korean Wood Science and Technology
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• v.50 no.6
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• pp.475-489
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• 2022

The objective of this study was to understand the conversion characteristics of glucose and xylose using the major monosaccharide standards for lignocellulosic biomass. The acid-catalyzed organosolv pretreatment conducted using ethanol was significantly different from the acid-catalyzed process conducted in an aqueous medium. 5-hydroxymethylfurfural (5-HMF), levulinic acid and furfural were produced from glucose conversion. The maximum yield of 5-HMF was 5.5%, at 200℃, when 0.5% sulfuric acid was used. The maximum yield of levulinic acid was 21.5%, at 220℃, when 1.0% sulfuric acid was used. Furfural was produced from xylose conversion and under 0.5% sulfuric acid, furfural reached the maximum yield 48.5% at 210℃. Ethyl levulinate and methyl levulinate were also formed from the glucose standard following the esterification reaction conducted under conditions of the combined conversion method, which proceeded under both ethanol-rich and water-rich conditions.

• Korean Journal of Pharmacognosy
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• v.36 no.3 s.142
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• pp.235-239
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• 2005

Changes in chemical composition of the ethanolic extract of roasted Asparagi Tuber were investigated by HPLC. One dramatically increased peak $(t_R\;14.85 min)$ was isolated by silica gel column chromatograph and identified as 5-hydroxymethyl furfural (HMF) by comparing its $1^H-NMR$ data with that of a commercial standard. HMF content reached its maximum level at $190^{\circ}C$ for 60 minutes. Under these conditions, HMF contents in the roasted Asparagi Tuber was increased about thirteen times (9.26mg/g) over the not-roasted control (0.71 mg/g). No significant differences were found in macrophage-activating, prolyl endopeptidase-inhibiting, antioxidative (DPPH), anti-coagulating (activated partial thromboplastin times), and ACE-inhibiting activities between roasted and not-roasted Asparagi Tuber.

• Korean Journal of Pharmacognosy
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• v.38 no.2 s.149
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• pp.133-138
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• 2007

Regarding chemical changes in oriental drugs after food processing such as roasting, fermentation, and extrusion, fifty commonly-used medicinal plants were investigated. As a result, Aurantii nobilis Pericarpium (a tangerine peel from Citrus unshu Markovich) showed remarkably different HPLC profiles after being roasted. An increased peak was isolated by repeated chromatography and identified as 5-hydroxymethyl furfral (5-HMF) by means of instrumental analyses. The 5-HMF content of Aurantii nobilis Pericarpoum reached its maximum level after being roasted for 30 min at 225$^{\circ}C$ (49.2 mg/g extract, ca 42 times of increase over untreated control). Although there were no significant changes in in vitro biological activity such as antioxidative, anti-dementia, anti-hypertension, anti-coagulation, or cytotoxicity, before and after roasting process, our results suggested that simple heat treatment might improve the value of the above oriental drug since 5-HMF has been known to possess inhibitory activities toward nitric oxide formation, tyrosinase, and sickling of red blood cells.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1319-1327
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• 2009

Marine red algae of genus Laurencia are becoming the most important resources to produce unique natural metabolites with wide bioactivities. However, reports related to Laurencia undulata, an edible species used as folk herb, are rarely found to date. In this research, 5-hydroxymethyl-2-furfural (5-HMF) was isolated and characterized by nuclear magnetic resonance (NMR) from Laurencia undulata as well as other marine algae. The following characteristics of 5-HMF were systematically evaluated: its antioxidant activities, such as typical free-radicals scavenging in vitro by electron spin resonance spectrometry (ESR) and intracellular reactive oxygen species (ROS) scavenging; membrane protein oxidation; oxidative enzyme myeloperoxidase (MPO) inhibition; as well as expressions of antioxidative enzymes glutathione (GSH) and superoxide dismutase (SOD) on the gene level using the polymerase chain reaction (PCR) method. The results demonstrated that 5-HMF could be developed as a novel marine natural antioxidant or potential precursor for practical applications in the food, cosmetic, and pharmaceutical fields.

• Korean Journal of Veterinary Service
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• v.19 no.2
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• pp.172-179
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• 1996

This study was to investigate the properties such as amounts of moisture, inverted sugar, cane sugar and 5-(hydroxymethyl)-2-furfural (HMF) in feeding-honey(n=45) and wild-honey (n=3) harvested in Chonbuk area from April to November 1995. The results obtained were summarized as follows ; The average percentages of moisture in both feeding- and wild-honey was 20.2%(range, 17.5~23.1) and 20.7%(19.4~22.2). And those of inverted sugar/cane sugar in both honeies were 64.4%(55.8~69.3)/6.8%(1.0~l5.7) and 68.9%(68.5~69.8)/3.1%(2.5~3.7), in seasonal analysis those were 65.9%/5.3% in spring, 65.7%/6.6% in summer, 62.1%/8.0% in autumn, respectively. On the other hand, the average amounts of HMF in both honeies were 44.86mg/kg(22.6~68.6) and 7.0mg/kg(6.2~7.6), its average difference between both honeies were about 37.86mg/kg regardless of region and season.

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.667-674
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• 2014

Twenty-five Saccharomyces cerevisiae strains were screened for the highest sugar tolerance, ethanol-tolerance, ethanol production, and inhibitor resistance, and S. cerevisiae KL5 was selected as the best strain. Inhibitor cocktail (100%) was composed of 75 mM formic acid, 75 mM acetic acid, 30 mM furfural, 30 mM hydroxymethyl furfural (HMF), and 2.7 mM vanillin. The cells of strain KL5 were treated with ${\gamma}$-irradiation, and among the survivals, KL5-G2 with improved inhibitor resistance and the highest ethanol yield in the presence of inhibitor cocktail was selected. The KL5-G2 strain was adapted to inhibitor cocktail by sequential transfer of cultures to a minimal YNB medium containing increasing concentrations of inhibitor cocktail. After 10 times of adaptation, most of the isolated colonies could grow in YNB with 80% inhibitor cocktail, whereas the parental KL5 strain could not grow at all. Among the various adapted strains, the best strain (KL5-G2-A9) producing the highest ethanol yield in the presence of inhibitor cocktail was selected. In a complex YP medium containing 60% inhibitor cocktail and 5% glucose, the theoretical yield and productivity (at 48 h) of KL5-G2-A9 were 81.3% and 0.304 g/l/h, respectively, whereas those of KL5 were 20.8% and 0.072 g/l/h, respectively. KL5-G2-A9 reduced the concentrations of HMF, furfural, and vanillin in the medium in much faster rates than KL5.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.389-397
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• 2016

In this study, ethanol was produced from a biomass hydrolysate that had been treated by electrodialysis (ED) and Amberlite XAD resin to remove fermentation inhibitors. Most of the acetic acid (95.6%) was removed during the ED process. Non-ionizable compounds such as total phenolic compounds, 5-hydroxymethyl furfural, and furfural were effectively removed by the XAD resin treatment. Ethanol production was improved when the ED-treated hydrolysate was treated with XAD-4 resin for a short reaction time. The highest ethanol production from ED-treated hydrolysate was $6.16g/{\ell}$ (after 72 h of fermentation) when the treatment with XAD-4 resin was for 5 min. Among the lignin-derived fermentation inhibitors tested, syringaldehyde in low concentrations (1 and 2 mM) in the hydrolysate increased ethanol production, whereas a high concentration (5 mM) inhibited the ethanol production process. A synthetic medium containing syringaldehyde and ferulic acid was prepared to investigate the synergistic effect of inhibitors on ethanol fermentation. Ethanol production decreased in the mixture of 1 mM syringaldehyde and 1 mM ferulic acid, implying that the effect of ferulic acid on ethanol fermentation is comparable to that of syringaldehyde.

• Natural Product Sciences
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• v.20 no.3
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• pp.182-190
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• 2014

An ultra-performance liquid chromatography (UPLC) coupled with electrospray ionization (ESI) tandem mass spectrometry (MS) method was established for quantitative analysis of twelve components, allantoin (1), morroniside (2), 5-hydroxymethyl-2-furfural (5-HMF) (3), loganin (4), coumarin (5), cinnamic acid (6), mesaconitine (7), cinnamaldehyde (8), hypaconitine (9), aconitine (10), alisol B (11), and alisol B acetate (12) in a Palmijihwang-hwan decoction. The twelve constituents were separated on a UPLC BEH C18 column ($2.1{\times}100mm$, $1.7{\mu}m$) at a column temperature of $40^{\circ}C$ by gradient elution with 0.1% (v/v) formic acid in water and acetonitrile as the mobile phase. The flow rate was 0.3 mL/min and the injection volume was $2.0{\mu}L$. Calibration curves of all compounds were acquired with values of the correlation coefficient ${\geq}0.99$ within the test ranges. The limits of detection and quantification for all analytes were 0.01 - 4.53 ng/mL and 0.03 - 13.60 ng/mL, respectively. The concentrations of the compounds 1 - 9 and 12 were 72.83, 4389.00, 4859.00, 3155.17, 223.67, 33.50, 1.97, 518.00, 2.25, and $25.00{\mu}g/g$, respectively. However, compounds 10 and 11 were not detected.