TY - JOUR
T1 - The contribution of coloured Maillard reaction products to the total colour of browned glucose/L-alanine solutions and studies on their formation
AU - Hofmann, Thomas
AU - Heuberger, Simone
PY - 1999
Y1 - 1999
N2 - Thermal treatment of aqueous solutions of glucose and L-alanine in the presence of furan-2-carboxaldehyde (mixture I) resulted in the formation of a variety of coloured compounds, amongst which (1R,8aR)-and (1S,8aR)-4-(2-furyl)-7-[(2-furyl)methylidene]-2-hydroxy-2H,7H,8aH-pyrano[2,3-b] pyran-3-one (1a/1b) and 3,5-dihydroxy-2-[(E)-(2-furyl)methylidene]methyl-5,6-dihydropyran-4-one(2) were identified as the most intense by application of the colour dilution analysis (CDA). To study how the colorant formation is influenced by the solvent, the Maillard mixture was then heated in a water/methanol mixture (mixture II). Besides 1a/1b and 2, additional coloured compounds were detected in mixture II, amongst which (E)- and (Z)-6-hydroxymethyl-2-methoxy-4-[(2-furyl)methylene]-2H-pyran-3-one (3a/3b), (E)- and (Z)-2-methoxy-4-[(2-furyl)methylene]-2H-pyran-3-one (4a/4b) as well as (1R,8aR)- and (1S,8aR)-4-(2-furyl)-7-[(2-furyl)methylidene]-2-methoxy-2H,7H,8aH-pyrano[2,3-b] pyran-3-one (5a/5b) could be distinguished from the less colour-active by application of CDA. To measure the contribution of these colorants to the overall colour of the browned Maillard mixtures I and II, colour activity values were calculated as the ratio of the concentration to the visual detection threshold of each colorant. By application of this colour activity concept, 3.3% of the total colour of the Maillard mixture II was shown to be caused by the 2H,7H,8aH-pyrano[2,3-b]pyran-3-one chromophore (1a/1b and 5a/5b). Based on a labelling experiment with glucose-6-[13C1], the formation pathway leading to this key chromophore, involving a retro-aldol cleavage of the C(6) carbon from the hexose skeleton, was clarified.
AB - Thermal treatment of aqueous solutions of glucose and L-alanine in the presence of furan-2-carboxaldehyde (mixture I) resulted in the formation of a variety of coloured compounds, amongst which (1R,8aR)-and (1S,8aR)-4-(2-furyl)-7-[(2-furyl)methylidene]-2-hydroxy-2H,7H,8aH-pyrano[2,3-b] pyran-3-one (1a/1b) and 3,5-dihydroxy-2-[(E)-(2-furyl)methylidene]methyl-5,6-dihydropyran-4-one(2) were identified as the most intense by application of the colour dilution analysis (CDA). To study how the colorant formation is influenced by the solvent, the Maillard mixture was then heated in a water/methanol mixture (mixture II). Besides 1a/1b and 2, additional coloured compounds were detected in mixture II, amongst which (E)- and (Z)-6-hydroxymethyl-2-methoxy-4-[(2-furyl)methylene]-2H-pyran-3-one (3a/3b), (E)- and (Z)-2-methoxy-4-[(2-furyl)methylene]-2H-pyran-3-one (4a/4b) as well as (1R,8aR)- and (1S,8aR)-4-(2-furyl)-7-[(2-furyl)methylidene]-2-methoxy-2H,7H,8aH-pyrano[2,3-b] pyran-3-one (5a/5b) could be distinguished from the less colour-active by application of CDA. To measure the contribution of these colorants to the overall colour of the browned Maillard mixtures I and II, colour activity values were calculated as the ratio of the concentration to the visual detection threshold of each colorant. By application of this colour activity concept, 3.3% of the total colour of the Maillard mixture II was shown to be caused by the 2H,7H,8aH-pyrano[2,3-b]pyran-3-one chromophore (1a/1b and 5a/5b). Based on a labelling experiment with glucose-6-[13C1], the formation pathway leading to this key chromophore, involving a retro-aldol cleavage of the C(6) carbon from the hexose skeleton, was clarified.
KW - C labelling experiments
KW - Colour activity value
KW - Coloured compounds
KW - Maillard reaction
KW - Non-enzymatic browning
UR - http://www.scopus.com/inward/record.url?scp=0002433094&partnerID=8YFLogxK
U2 - 10.1007/s002170050369
DO - 10.1007/s002170050369
M3 - Article
AN - SCOPUS:0002433094
SN - 0044-3026
VL - 208
SP - 17
EP - 26
JO - Zeitschrift fur Lebensmittel -Untersuchung und -Forschung
JF - Zeitschrift fur Lebensmittel -Untersuchung und -Forschung
IS - 1
ER -