Formation of aroma-active Strecker-aldehydes by a direct oxidative degradation of Amadori compounds

Citation
T. Hofmann et P. Schieberle, Formation of aroma-active Strecker-aldehydes by a direct oxidative degradation of Amadori compounds, J AGR FOOD, 48(9), 2000, pp. 4301-4305
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Agricultural Chemistry","Chemistry & Analysis
Journal title
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
ISSN journal
0021-8561 → ACNP
Volume
48
Issue
9
Year of publication
2000
Pages
4301 - 4305
Database
ISI
SICI code
0021-8561(200009)48:9<4301:FOASBA>2.0.ZU;2-C
Abstract
alpha-Dicarbonyls, generated by sugar degradation, catalyze the formation o f the so-called Strecker aldehydes from a-amino acids. To check the effecti veness of Amadori compounds (suggested as important intermediates in a-dica rbonyl formation from carbohydrates) in Strecker aldehyde formation, the am ounts of phenylacetaldehyde (PA) formed from either an aqueous solution of L-phenylalanine/glucose or the corresponding Amadori compound N-(1-deoxy-D- fructosyl-1-yl)-L-phenylalanine (ARP-Phe) were compared. The results reveal ed the ARP-Phe asa much more effective precursor in PA generation. On the c ontrary, a binary mixture of glucose/phenylalanine yielded preferentially p henylacetic acid, in particular, when reacted in the presence of oxygen and copper ions. Further model experiments gave evidence that a transition-met al-catalyzed oxidation of the ARP-Phe by air oxygen into the 2-hexosulose-( phenylalanine) imine is the key step responsible for the favored formation of phenylacetaldehyde from the Amadori compound. This mechanism might expla in differences in the ratios of Strecker aldehydes and the corresponding ac ids depending on the structures of carbohydrate degradation products involv ed.