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Mechanism of Browning in Fresh Highbush Blueberry Fruit (Vaccinium corymbosum L). Partial Purification and Characterisation of Blueberry Polyphenol Oxidase

✍ Scribed by Kader, Farid; Rovel, Bernard; Girardin, Michel; Metche, Maurice

Publisher: John Wiley and Sons
Year: 1997
Tongue: English
Weight: 366 KB
Volume: 73
Category: Article
ISSN: 0022-5142
DOI: 10.1002/(sici)1097-0010(199704)73:4<513::aid-jsfa763>3.0.co;2-t

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✦ Synopsis

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 bu †er (pH 6É5) and detergents such as Triton X-100. PPO has been puriÐed 19-fold, by ultraÐltration, ammonium sulphate precipitation and hydrophobic chromatography. Native-PAGE of the puriÐed fraction revealed the presence of two isoforms. PPO has an observed optimum pH at 4É0, followed by a shoulder at pH 5É0. Ca †eic acid is the best substrate (100%), followed by chlorogenic acid (60%) and pyrocatechol (32É5%). No activity was detected towards catechin, protocatechuic acid, resorcinol and monophenols.

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Mechanism of Browning in Fresh Highbush

Mechanism of Browning in Fresh Highbush Blueberry Fruit (Vaccinium corymbosum L). Role of Blueberry Polyphenol Oxidase, Chlorogenic Acid and Anthocyanins

✍ Kader, Farid; Rovel, Bernard; Girardin, Michel; Metche, Maurice 📂 Article 📅 1997 🏛 John Wiley and Sons 🌐 English ⚖ 216 KB 👁 2 views

Browning reactions which occurred after crushing fresh blueberries (V accinium corymbosum L) were followed by determination of chlorogenic acid colour density, polymer colour and the level of polymers. A polyphenol oxidase (PPO) activity plays a dominant role in enzymatic browning. Peroxidase (POD)