• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.331-336
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• 2006

Effects of high temperature and pressure treatment on garlic (Allium sativum L.) treated at 110, 120, 130, 140, and $150^{\circ}C$ for 1, 2, 3, 4, and 5 hr were evaluated by investigating changes in antioxidant activities, and total polyphenol, total flavonoid, and 5-hydroxymethyl-2-furaldehyde (5-HMF) contents of garlic juice. Antioxidant activities, and total polyphenol, total flavonoid, and 5-HMF contents increased with increasing treated temperature and time. $IC_{50}$ (1.952 mg/g) was achieved at $150^{\circ}C$ for 4 hr, 50 times higher than untreated garlics. Highest total polyphenol content was 18.155 mg/g at $140^{\circ}C$ and 2 hr, seven times higher than untreated garlics. Highest total flavonoid content was $532.73\;{\mu}g/g$ at $150^{\circ}C$ and 1 hr, sixteen times higher than untreated garlics. 5-HMF content was highest (7,765.9 ppm) at $150^{\circ}C$ and 2 hr. Correlation coefficients among antioxidant activities, and total polyphenol, total flavonoid, and 5-HMF contents were very high (p<0.01).

• 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 Pharmacognosy
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• v.41 no.1
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• pp.58-61
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• 2010

Medicinal plant Rehmanniae Radix has long been used as traditional herbal medicine in Korea. In this study, we investigated quantitative changes of marker substance 5-hydroxymethyl-2-furaldehyde (5-HMF) in Rehmanniae Radix Preparata fermented with Ganoderma lucidum, Paecilomyces japonica, honey, and Nuruk, using HPLC according to the Korean Pharmacopoeia. As a result, 5-HMF was decreased in SDT and SYT, and increased in SST and SNT, comparing with control group. Quantitative increasing of 5-HMF is not exactly in direct proportion with fermentation, and it is need further studies to elucidate mechanism of quantitative changes by converted and newly produced substances with fermentation.

• 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 Journal of Agricultural Science
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• v.48 no.4
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• pp.899-910
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• 2021

This study was performed to suggest concentration methods leading to the production ofhoney with an excellent flavor by examining the effects of the concentration temperature and method on changes in 5-hydroxymethyl-2-furaldehyde (5-HMF) levels and the flavor components of honey. The 5-HMF contents of honey samples concentrated in a tray concentrator at 45, 50, 60, and 70℃ were 2.1, 2.3, 2.5, and 3.1 mg·kg^-1, respectively, demonstrating that the 5-HMF contents increased as the concentration temperatures were increased. The honey vacuum-concentrated at 70℃ showed a higher 5-HMF content than that at 60℃, similar to the tray-concentrated honey at different temperatures. The main and other minor flavor components of the honey were volatilized and significantly reduced after vacuum concentration. In the tray concentration, all of the honey samples concentrated at 40, 50, 60, and 70℃ showed flavor component patterns similar to each other, and most of the main and other minor flavor components in the honey were volatilized and significantly reduced after tray concentration. As such, most of the main and other minor flavor components of the honey were mostly removed at 70℃ after both the vacuum concentration and tray concentration processes. The effects of the concentration method and temperature on the viscosity, 5-HMF level, and flavor components of the honey were found to be significant in this study. Given that the components of honey were shown to undergo significant physicochemical changes depending on the concentration method used and temperature during laboratory-scale production, the concentration methods devised in this study can be applied industrially.

• 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 the Korean Wood Science and Technology
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• v.41 no.4
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• pp.287-292
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• 2013

Reaction of glucose and xylose to secondary hydrolysis of concentrated acid hydrolysis was quantitatively analyzed by $^1H$-NMR spectroscopic method. Anomeric hydrogen, furan and formic acid peaks were selected for quantitative analysis. The glucose was converted to the formic acid and the levulinic acid via the 5-hydroxymethylfurfural (HMF) but the xylose was converted to the fufural, which further degraded to the formic acid. The conversion to furans was slower for the glucose than the xylose. But the 5-HMF formed from the glucose was unstable in acidic aqueous medium, resulted in fast conversion to the levulinic acid and the formic acid. The furfural was relatively stable than 5-HMF at acidic aqueous medium.

• Journal of Microbiology and Biotechnology
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• v.28 no.12
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• pp.1999-2008
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• 2018

The compound 2,5-furandicarboxylic acid (FDCA), an important bio-based monomer for the production of various polymers, can be obtained from 5-hydroxymethylfurfural (HMF). However, efficient production of FDCA from HMF via biocatalysis has not been well studied. In this study, we report the identification of key genes that are involved in FDCA synthesis and then the engineering of Raoultella ornithinolytica BF60 for biocatalytic oxidation of HMF to FDCA using its resting cells. Specifically, previously unknown candidate genes, adhP3 and alkR, which were responsible for the reduction of HMF to the undesired product 2,5-bis(hydroxymethyl)furan (HMF alcohol), were identified by transcriptomic analysis. Combinatorial deletion of these two genes resulted in 85.7% reduction in HMF alcohol formation and 23.7% improvement in FDCA production (242.0 mM). Subsequently, an aldehyde dehydrogenase, AldH, which was responsible for the oxidation of the intermediate 5-formyl-2-furoic acid (FFA) to FDCA, was identified and characterized. Finally, FDCA production was further improved by overexpressing AldH, resulting in a 96.2% yield of 264.7 mM FDCA. Importantly, the identification of these key genes not only contributes to our understanding of the FDCA synthesis pathway in R. ornithinolytica BF60 but also allows for improved FDCA production efficiency. Moreover, this work is likely to provide a valuable reference for producing other furanic chemicals.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.627-632
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• 1991

The heat treatment indicators such as HMF contents, lactulose contents and whey protein denaturation rates were measured to refer to the heat treatment intensity of domestic market infant formulae. The HMF contents showed $21.0{\sim}43.9{\mu}mol/l:$ in the case of powder types, the HMF contents in enriched nutrient products(ii) were higher whereas in the case of liquid types they were packed in cans(i). The lactulose contents showed $2.5{\sim}11.4mg/100ml$ in the powder type and $27.0{\sim}164.8mg/100ml$ in the liquid type. There was much difference in the lactulose contents according to the product types. Compared with the ADPI standards, most of infant formulae were considered to be medium-heat class. The whey protein denaturation rates were $1.1{\sim}69.4%$ in the powder type and $37.4{\sim}71.3%$ in the liquid type.

• Food Science of Animal Resources
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• v.21 no.1
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• pp.56-63
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• 2001

In this study, three domestic and one foreign formulas for the infants up to 5 month old were examined to detect chemical changes such as pH, reactive sulfhydryl groups(RSH) content, 5-hydroxymethylfurfral(HMF) content, available lysine content, electrophoresis, and surface color caused by heat treatment for long term storage. In the SDS-polyacrylamide gel electrophoresis, A and B products showed similar pattern, while C product had a clearly distinguishable $\beta$-lacto-globulin band, but in casein, only D product showed a few strong casein band. RSH content, which indicate the extent of whey protein denaturation, ranged from 4.40 to 5.93 mmole/g protein. HMF content. which indicate the extent of Maillard reaction, ranged from 192 to 432 $\mu$mole/100g in formulas. B product showed the highest RSH and HMF content. Available lysine content ranged from 31 to 46 mg/g protein. Among them D product contain the highest available lysine content and others showed no significant difference. In conclusion, the domestic infant formulas showed higher RSH and HMF content than the foreign product and the available lysine content of the domestic products were lower than of the foreign product.