title: D-Galacturonic acid as a highly reactive compound in nonenzymatic browning. 1. Formation of browning active degradation products.
abstract: 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.
authors.affiliation: Institute of Food Technology and Food Chemistry, Technical University of Berlin, Berlin, Germany.
authors.forename: Maria-Anna
authors.initials: MA
authors.lastname: Bornik
authors.forename: Lothar W
authors.initials: LW
authors.lastname: Kroh
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D002384:Catalysis; D003517:Cyclopentanes / Q000737:chemistry; D005511:Food Handling; D005663:Furans / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry*; D006358:Hot Temperature; D015416:Maillard Reaction; D008956:Models, Chemical; D013237:Stereoisomerism
chemical_list: C436749:4,5-dihydroxy-2-cyclopentan-1-one; D000447:Aldehydes; D003517:Cyclopentanes; D005663:Furans; D006603:Hexuronic Acids; C064295:reductic acid; C007819:galacturonic acid