F. Richard-Forget, M. Rouet-Mayer, P. Goupy
Nov 1, 1992
Citations
1
Influential Citations
76
Citations
Quality indicators
Journal
Journal of Agricultural and Food Chemistry
Abstract
The oxidation of chlorogenic acid (CG), (+)-catechin (CA), (-)-epicatechin (EC), and 4-methylcatechol (4MC) catalyzed by apple polyphenol oxidase (PPO) was followed between pH 4 and 5 by polarography, spectrophotometry, and HPLC. In the presence of cysteine, the stoichiometry O 2 /phenol consumed was always close to 0.5 regardless of the time of measurement, the initial O 2 /phenol ratio, and the phenols tested at pH between 4 and 5. In the absence of cysteine, the observed stoichiometries greatly varied with the preceding factors