Document Detail

Characterization of polyphenol oxidase from the Manzanilla cultivar (Olea europaea pomiformis) and prevention of browning reactions in bruised olive fruits.
MedLine Citation:
PMID:  17628073     Owner:  NLM     Status:  MEDLINE    
The crude extract of the polyphenol oxidase (PPO) enzyme from the Manzanilla cultivar (Olea europaea pomiformis) was obtained, and its properties were characterized. The browning reaction followed a zero-order kinetic model. Its maximum activity was at pH 6.0. This activity was completely inhibited at a pH below 3.0 regardless of temperature; however, in alkaline conditions, pH inhibition depended on temperature and was observed at values above 9.0 and 11.0 at 8 and 25 degrees C, respectively. The thermodynamic parameters of substrate oxidation depended on pH within the range in which activity was observed. The reaction occurred according to an isokinetic system because pH affected the enzymatic reaction rate but not the energy required to carry out the reaction. In the alkaline pH region, browning was due to a combination of enzymatic and nonenzymatic reactions that occurred in parallel. These results correlated well with the browning behavior observed in intentionally bruised fruits at different temperatures and in different storage solutions. The use of a low temperature ( approximately 8 degrees C) was very effective for preventing browning regardless of the cover solution used.
Kharla A Segovia-Bravo; Manuel Jarén-Galan; Pedro García-García; Antonio Garrido-Fernandez
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-07-12
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  55     ISSN:  0021-8561     ISO Abbreviation:  J. Agric. Food Chem.     Publication Date:  2007 Aug 
Date Detail:
Created Date:  2007-08-01     Completed Date:  2007-10-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  6515-20     Citation Subset:  IM    
Food Biotechnology Department, Instituto de la Grasa (CSIC), Padre Garcia Tejero 4, 41012 Sevilla, Spain.
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MeSH Terms
Catechol Oxidase / metabolism*
Fruit / metabolism*
Hydrogen-Ion Concentration
Maillard Reaction*
Olea / enzymology*
Reg. No./Substance:
EC Oxidase

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