Inhibition of Apple Polyphenol Oxidase Activity by Procyanidins and Polyphenol Oxidation Products

• Published in: Journal of agricultural and food chemistry 2004-01, Vol.52 (1), p.122-130
• Main Authors: Le Bourvellec, Carine, Le Quéré, Jean-Michel, Sanoner, Philippe, Drilleau, Jean-François, Guyot, Sylvain
• Format: Article
• Language: English
• Subjects: Alcoholic beverages and cider; Beverages - analysis; Biflavonoids; Biological and medical sciences; Catechin - metabolism; Catechin - pharmacology; Catechol Oxidase - antagonists & inhibitors; Catechol Oxidase - metabolism; Chromatography, High Pressure Liquid; Enzyme Inhibitors - pharmacology; Fermented food industries; Flavonoids - metabolism; Food engineering; Food industries; Fruit - enzymology; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Kinetics; Life Sciences; Malus - enzymology; Oxidation-Reduction; Phenols - metabolism; Polyphenols; Proanthocyanidins; Quinic Acid - analogs & derivatives; Quinic Acid - metabolism
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf034461q

The rate of consumption of dissolved oxygen by apple polyphenol oxidase in cider apple juices did not correlate with polyphenol oxidase activity in the fruits and decreased faster than could be explained by the decrease of its polyphenolic substrates. The kinetics parameters of a crude polyphenol oxidase extract, prepared from apple (Braeburn cultivar), were determined using caffeoylquinic acid as a substrate. Three apple procyanidin fractions of n 80, 10.5, and 4 were purified from the parenchyma of cider apples of various cultivars. Procyanidins, caffeoylquinic acid, (−)-epicatechin, and a mixture of caffeoylquinic acid and (−)-epicatechin were oxidized by reaction with caffeoylquinic acid o-quinone in order to form oxidation products. All the fractions were evaluated for their inhibitory effect on PPO activity. Native procyanidins inhibited polyphenol oxidase activity, the inhibition intensity increasing with n. The polyphenol oxidase activity decreased by 50% for 0.026 g/L of the fraction of n 80, 0.17 g/L of the fraction of n 10.5, and 1 g/L of the fraction of n 4. The inhibitory effect of oxidized procyanidins was twice that of native procyanidins. Oxidation products of caffeoylquinic acid and (−)-epicatechin also inhibited polyphenol oxidase. Keywords: Cider; browning; tannin; polyphenols; enzymatic inhibition