5-hydroxymethylfurfural and 5-hydroxymethyl-2-furoic-acid

The aim of this study was to develop a multi-analyte UHPLC method for furans and to apply it to commercial coffee samples as well as commercial roasting trials. Furans, as rising time-temperature indicators (TTIs), promised to be an alternative to unsatisfactory roasting temperature measurements. Consequently, a UHPLC-UV method for the determination of 5-hydroxymethyl-2-furfural (HMF), 5-hydroxymethyl-2-furoic acid (HMFA), 2-furfural (F), 5-methylfurfural (MF), 2-furyl methyl ketone (FMC), 2-furoic acid (FA), and for 3-caffeoylquinic acid (3-CQA) was developed and validated. Commercial roasted coffee beans contained 77.7-322 mg/kg HMF, 73.3-158 mg/kg HMFA, 109-200 mg/kg 2-F, 157-209 mg/kg MF, 12.3-32.8 mg/kg FMC, and 137-205 mg/kg FA. Roasting trial samples showed strong rising HMF contents (max.: Arabica: 769 mg/kg, Robusta: 364 mg/kg) followed by a distinct decline. Only MF and FA appeared as steady rising TTIs in the roasting process in Arabica and Robusta beans. 3-CQA fitted well as a decreasing TTI as expected.

Topics: Chlorogenic Acid; Chromatography, High Pressure Liquid; Coffee; Food Analysis; Food-Processing Industry; Furaldehyde; Furans; Hot Temperature; Seeds

Lignocellulosic biomass serves as a potential alternative feedstock for production of bacterial nanocellulose (BNC), a high-value-added product of bacteria such as Gluconacetobacter xylinus. The tolerance of G. xylinus to lignocellulose-derived inhibitors (formic acid, acetic acid, levulinic acid, furfural, and 5-hydroxymethylfurfural) was investigated. Whereas 100 mM formic acid completely suppressed the metabolism of G. xylinus, 250 mM of either acetic acid or levulinic acid still allowed glucose metabolism and BNC production to occur. Complete suppression of glucose utilization and BNC production was observed after inclusion of 20 and 30 mM furfural and 5-hydroxymethylfurfural, respectively. The bacterium oxidized furfural and 5-hydroxymethylfurfural to furoic acid and 5-hydroxymethyl-2-furoic acid, respectively. The highest yields observed were 88% for furoic acid/furfural and 76% for 5-hydroxymethyl-2-furoic acid/5-hydroxymethylfurfural. These results are the first demonstration of the capability of G. xylinus to tolerate lignocellulose-derived inhibitors and to convert furan aldehydes.

Topics: Acetic Acid; Aldehydes; Cellulose; Formates; Furaldehyde; Furans; Gluconacetobacter xylinus; Glucose; Industrial Microbiology; Levulinic Acids; Lignin

5-Hydroxymethylfurfural (HMF) is naturally formed during food processing or cooking activities, giving its ubiquity in the Western diet. HMF could be metabolised to 5-sulfooxymethylfurfural making HMF potentially harmful in an extent unknown at present. Coffee is the main exposure source. Occurrence of HMF, 5-hydroxymethyl-2-furoic acid (HMFA) and 2-furoic acid (FA) were measured in commercial ground coffee and soluble coffee marketed in Spain. Levels of 110, 625, 1734, 2480 mg HMF/kg were obtained for natural, blend, torrefacto and soluble coffee, respectively, giving four classes significantly different. Soluble coffee showed the largest variability in HMF. Levels of HMFA and FA did not change significantly being about 600 mg/kg. Dietary exposure to HMF coffee to consumption in the total Spanish population was estimated to be 8.57 mg/day by using a deterministic approach. However, median level was recalculated to 5.26 mg HMF/day when specific contribution of each type of ground and soluble coffee in the consumption habits was considered. Resultant value is above of the threshold of concern (1600 microg HMF/day, mTAMDI). A level of 8.57 mg HMF/day in persons with high consumption habits (95th percentile) was calculated for risk assessment.

Topics: Chromatography, High Pressure Liquid; Coffee; Diet; Environmental Exposure; Environmental Monitoring; Feeding Behavior; Food Analysis; Food Contamination; Furaldehyde; Furans; Humans; Risk Assessment; Spain

5-Hydroxymethylfurfural (HMF) is formed in carbohydrate-rich food during acid-catalysed dehydration and in the Maillard reaction from reducing sugars. HMF is found in mg quantities per kg in various foods. HMF is mainly metabolised to 5-hydroxymethyl-2-furoic acid (HMFA), but unknown quantities of the mutagenic 5-sulphoxymethylfurfural (SMF) may also be formed, making HMF potentially hazardous to humans. We determined the HMF content in Norwegian food items and estimated the dietary intake of HMF in 53 volunteers by means of 24h dietary recall. The estimated intakes of HMF were correlated with urinary excretion of HMFA. Coffee, prunes, dark beer, canned peaches and raisins had the highest levels of HMF. The 95th percentile of the estimated daily dietary intake of HMF and the 24h urinary excretion of HMFA were 27.6 and 28.6mg, respectively. Coffee, dried fruit, honey and alcohol were identified as independent determinants of urinary HMFA excretion. Most participants had lower estimated HMF intake than the amount of HMFA excreted in urine. In spite of this there was a significant correlation (r=0.57, P<0.001) between the estimated HMF intake and urinary HMFA. Further studies are needed to reveal alternative sources for HMF exposure.

Topics: Adult; Chromatography, High Pressure Liquid; Diet; Female; Food Analysis; Furaldehyde; Furans; Humans; Male; Norway

The formation of 5-hydroxymethyl-2-furfural (HMF) and 5-hydroxymethyl-2-furoic acid (HMFA) during roasting of coffee was studied. At 240 degrees C the maximum concentration of HMF occurs after 3 min with a quick degradation up to 10 min when most of the HMF has disappeared again. Similar to 5-hydroxymethyl-furfural, HMFA is formed in coffee but not in a model system consisting of sucrose, alanine with or without chlorogenic acid. It was shown that HMFA is produced from different precursors than HMF namely glyceraldehyde and pyruvate. The comparison of the laboratory scale roasting with industrial roasting showed that 5-hydroxymethyl-furfural decreases with a higher degree of roasting whereas HMFA did not change. In the laboratory scale experiments, the highest concentration of 5-hydroxymethyl-furfural in coffee (909 microg/g) was obtained after 3 min and the maximum concentration of HMFA after 4 min (150 microg/g). Industrially roasted coffee contained up to 350 microg/g 5-hydroxymethyl-furfural and 140 microg/g HMFA.

Topics: Alanine; Chlorogenic Acid; Coffea; Food Handling; Furaldehyde; Furans; Glyceraldehyde; Hot Temperature; Pyruvic Acid; Seeds; Sucrose; Time Factors