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Mechanism of Browning in Fresh Highbush Blueberry Fruit ( Vaccinium corymbosum L). Partial Purification and Characterisation of Blueberry Polyphenol Oxidase
Author(s) -
Kader Farid,
Rovel Bernard,
Girardin Michel,
Metche Maurice
Publication year - 1997
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199704)73:4<513::aid-jsfa763>3.0.co;2-t
Subject(s) - chemistry , polyphenol oxidase , chlorogenic acid , vaccinium , arbutin , browning , polyphenol , caffeic acid , catechin , protocatechuic acid , chromatography , resorcinol , food science , extraction (chemistry) , botany , biochemistry , enzyme , biology , antioxidant , peroxidase , organic chemistry
The most efficient method for polyphenol oxidase (PPO) extraction from Highbush blueberry fruits was the preparation of an acetone powder. No activity was detected after direct extraction with phosphate buffer (pH 6·5) and detergents such as Triton X‐100. PPO has been purified 19‐fold, by ultrafiltration, ammonium sulphate precipitation and hydrophobic chromatography. Native‐PAGE of the purified fraction revealed the presence of two isoforms. PPO has an observed optimum pH at 4·0, followed by a shoulder at pH 5·0. Caffeic acid is the best substrate (100%), followed by chlorogenic acid (60%) and pyrocatechol (32·5%). No activity was detected towards catechin, protocatechuic acid, resorcinol and monophenols. © 1997 SCI.