Polyphenols of avocado (Persea americana) and their endogenous oxidation.

Polyphenols from the peel, pulp, seed and seed coat of avocado were separated and identified by paper chromatography. Catechin, epi-catechin and 3 leucoanthocyanidins were present in all the tissues of the fruit. Cis- and trans-chlorogenic acids and 2 flavonol glycosides were present exclusively in the peel. p-Coumaric and caffeic acids were detected only in pulp, while isoflavone was present in both pulp and seed coat. Chromatograms sprayed with endogenous polyphenol oxidase preparations showed that catechin and epi-catechin were the major browning substrates in all the tissues of avocado, and leucoanthocyanidins considerably contributed towards browning.