- Characteristic flavor formation of thermally processed N-(1-deoxy-α-D-ribulos-1-yl)-glycine: Decisive role of additional amino acids and promotional effect of glyoxal
-
The role of amino acids and α-dicarbonyls in the flavor formation of Amadori rearrangement product (ARP) during thermal processing was investigated. Comparisons of the volatile compounds and their concentrations when N-(1-deoxy-α-D-ribulos-1-yl)-glycine r
- Zhan, Huan,Cui, Heping,Yu, Junhe,Hayat, Khizar,Wu, Xian,Zhang, Xiaoming,Ho, Chi-Tang
-
-
- Formation of Phenolic Compounds from d -Galacturonic Acid
-
Aqueous d-galacturonic acid (d-GalA) model systems treated at 130 °C at different pH values show an intense color formation, whereas other reducing sugars, such as d-galactose (d-Gal), scarcely react. GC-MS measurements revealed the presence of several ph
- Urbisch, Alexandra,Einhorn-Stoll, Ulrike,Kastner, Hanna,Drusch, Stephan,Kroh, Lothar W.
-
-
- D-galacturonic acid as a highly reactive compound in nonenzymatic browning. 1. Formation of browning active degradation products
-
Thermal treatment of an aqueous solution of d-galacturonic acid at pH 3, 5, and 8 led to rapid browning of the solution and to the formation of carbocyclic compounds such as reductic acid (2,3-dihydroxy-2-cyclopenten-1-one), DHCP (4,5-dihydroxy-2-cyclopenten-1-one), and furan-2-carbaldehyde, as degradation products in weak acidic solution. Studies on their formation revealed 2-ketoglutaraldehyde as their common key intermediate. Norfuraneol (4-hydroxy-5-methyl-3-(2H)-furanone) is a typical alkaline degradation product and formed after isomerization. Further model studies revealed reductic acid as an important and more browning active compound than furan-2-carbaldehyde, which led to a red color of the model solution. This red-brown color is also characteristic of thermally treated uronic acid solutions.
- Bornik, Maria-Anna,Kroh, Lothar W.
-
p. 3494 - 3500
(2013/06/05)
-
- The multiple Maillard reactions of ribose and deoxyribose sugars and sugar phosphates
-
Ribose 5-phosphate (R5P) undergoes the Maillard reaction with amines at significantly higher rates than most other sugars and sugar phosphates. The presence of an intramolecular phosphate group, which catalyzes the early stages of the Maillard reaction, provides the opportunity for the R5P molecule to undergo novel reaction paths creating unique Maillard products. The initial set of reactions leading to an Amadori product (phosphorylated) and to an α-dicarbonyl phosphate compound follows a typical Maillard reaction sequence, but an observed phosphate hydrolysis accompanying the reaction adds to the complexity of the products formed. The reaction rate for the loss of R5P is partially dependent on the pKa of the amine but also is correlated to the protonation of an early intermediate of the reaction sequence. In the presence of oxygen, a carboxymethyl group conjugated to the amine is a major product of the reaction of R5P with N-acetyllysine while little of this product is generated in the absence of oxygen. Despite lacking a critical hydroxyl group necessary for the Maillard reaction, 2-deoxyribose 5-phosphate (dR5P) still generates an Amadori-like product (with a carbonyl on the C-3 carbon) and undergoes phosphate cleavage. Two highly UV-absorbing products of dR5P were amine derivatives of 5-methylene-2-pyrrolone and 2-formylpyrrole. The reaction of dR5P with certain amines generates a set of products that exhibit an interesting absorbance at 340 nm and a high fluorescence.
- Munanairi, Admire,O'Banion, Steven K.,Gamble, Ryan,Breuer, Elizabeth,Harris, Andrew W.,Sandwick, Roger K.
-
p. 2575 - 2592
(2008/03/27)
-
- The effect of high pressure on the formation of volatile products in a model Maillard reaction
-
Reaction progress in the formation and subsequent decay of several of the volatile products from a model Maillard reaction between lysine and xylose has been followed at pH 7 and 10 and at elevated pressures. At low pH, the buildup and decay of 5-methyl-4-hydroxy-3(2H)-furanone and several minor products were observed. The application of high pressure results in a much diminished maximum concentration of each although the time to the maximum is unaffected. At pH 10, products contain nitrogen heterocycles with 2-methylpyrazine being the principal one which builds up and only slowly decays with time. Again, the yield is greatly reduced by pressure. The results are interpreted in terms of the inhibition by pressure of the formation of the precursor the Amadori rearrangement product which affects subsequent products. In some instances rates of formation are also found to be slightly inhibited while degradation of these products is accelerated. The corresponding mechanisms are examined in the light of these results.
- Bristow, Mark,Isaacs, Neil S.
-
p. 2213 - 2218
(2007/10/03)
-
- Analysis of furanone, pyranone, and new heterocyclic colored compounds from sugar-glycine model maillard systems
-
Aqueous sugar (xylose or glucose)-glycine model systems were refluxed for 2 h with the pH maintained at 5. Reverse-phase HPLC of the total reaction products gave two resolved peaks (one of which was colored) for the xylose system and five resolved peaks (two of which were colored) for the glucose system. The components responsible for these peaks were isolated from the ethyl acetate extracts by semipreparative HPLC. Using mainly NMR, the colored compound from the xylose system was identified as the new 2-acetyl-6- (hydroxymethyl)-5,6-dihydro-4H-pyridinone. The colored compounds from the glucose system were most likely to be two novel cis/trans ring isomers of the related new compound 2-acetyl-6-hydroxy-7-(hydroxymethyl)-1,5,6,7-tetrahydro- 4H-azepinone. These compounds are the first one-ring structures isolated from sugar-amino acid model systems that are reported to be colored. Two of the colorless components of the glucose system were identified, mainly by NMR experiments, as the related compounds 4-hydroxy-2-(hydroxymethyl)-5-methyl- 3(2H)-furanone and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyranone. The remaining compound from the glucose system and the colorless compound from the xylose system were identified as 5-(hydroxymethyl)furfural and 4-hydroxy- 5-methyl-3(2H)-furanone, respectively.
- Ames, Jennifer M.,Bailey, Richard G.,Mann, John
-
p. 438 - 443
(2007/10/03)
-
- Formation of Hydroxyfuranone and Hydroxypyranone Derivatives with DNA-Breaking Activity in the Maillard Reaction of Glucose and Albumin under Physiological Conditions
-
Formation of DNA breaking hydroxyfuranone and hydroxypyranone derivatives in the Maillard reaction of glucose and bovine serum albumin (BSA) under physiological conditions was investigated. A mixture of glucose and BSA was incubated at 37 deg C in water or in 1 M phosphate buffer (pH 7.4). The ethyl acetate/2-propanol extract of the reaction mixtures showed significant DNA breaking activity against supercoiled DNA especially in the presence of Fe(III) ion. Gas chromatography/mass spectrometry analysis of the mixture revelaed the formation of DNA breaking hydroxyfuranones (HMF and DMHF) and hydroxypyranone (DDMP).
- Hiramoto, Kazuyuki,Ishihara, Akira,Sakui, Norihiro,Daishima, Shigeki,Kikugawa, Kiyomi
-
p. 101 - 104
(2007/10/03)
-
- Quantitative Model Studies on the Effectiveness of Different Precursor Systems in the Formation of the Intense Food Odorants 2-Furfurylthiol and 2-Methyl-3-furanthiol
-
The yields of the two intense food odorants 2-furfurylthiol (FFT) and 2-methyl-3-furanthiol (MFT) obtained by heating mixtures of possible precursors in model systems varying in temperature, pH value, or water content were determined by using stable isotope dilution assays. Although pentoses generated much higher amounts of FFT and MFT than hexoses when heated in the presence of cysteine, glucose and rhamnose also gave significant yields. Studies on several intermediates indicated the highest yields for MFT (1.4 mol %) when hydroxyacetaldehyde and mercapto-2-propanone were reacted for 6 min at 180 °C in the absence of water. Both intermediates also generated significant amounts of FFT (0.05 mol %). However, the system furan-2-aldehyde/H2S showed a 10 times higher efficiency in generating FFT. Thiamin and norfuraneol/cysteine were less effective precursors of MFT. The results imply that different formation pathways may run in parallel during food processing and may account for the different amounts of the two odorants present in the respective food.
- Hofmann,Schieberle
-
p. 235 - 241
(2007/10/03)
-
- Method for producing 4-hydroxy-5-methyl-3[2H]-furanone and uses of same
-
Disclosed herein is a method for producing 4-hydroxy-5-methyl-3[2H]-furanone and new uses thereof. 4-hydroxy-5-methyl-3[2H]-furanone may be extracted from the plants of Pinaceae species and may advantageously be used as an anti-oxidant or for whitening the skin. The compound or extracts containing same is not irritative to the skin and can safely be applied to the skin.
- -
-
-
- Process for making furanones
-
This deals with a process for making furanones having the formula: STR1 wherein R represents a hydrogen atom or the methyl or ethyl group.
- -
-
-
- Process of the preparation of hydroxyfurenones
-
A novel technique for the preparation of 4-hydroxy-5-alkyl-3-oxo-2H-furans is disclosed wherein the reaction product of an alpha-alkyl diglycolic acid diester and an oxalic acid diester is cyclized, hydrolyzed and decarboxylated. Alternatively, the corresponding 2,5-dialkyl product can be prepared by an intermediate alkylation step.
- -
-
-