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Effect of different levels of CO 2 on the antioxidant content and the polyphenol oxidase activity of ‘Rocha’ pears during cold storage
Author(s) -
GalvisSánchez Andrea C,
Fonseca Susana C,
GilIzquierdo Ángel,
Gil María I,
Xavier Malcata F
Publication year - 2006
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/jsfa.2359
Subject(s) - flavonols , chemistry , flesh , food science , browning , titratable acid , ascorbic acid , arbutin , polyphenol oxidase , cold storage , hydroxycinnamic acid , vitamin c , polyphenol , dehydroascorbic acid , botany , antioxidant , horticulture , biochemistry , enzyme , biology , peroxidase
Pears ( Pyrus communis L. cv. ‘Rocha’) were exposed to air or controlled atmosphere (CA) containing various concentrations of CO 2 : 0, 0.5 and 5 kPa, all with 2 kPa O 2 . After 4 months of storage at 2 °C, the fruits were transferred to air at room temperature, and assessed in terms of soluble solids, titratable acidity, pH, incidence of brown heart and flesh browning, phenolic content, vitamin C content and polyphenol oxidase activity. By 4 months of storage, soluble solids and pH increased, and acidity decreased relative to harvest, but no differences were detected between pears stored under air or any of the CA tested. Higher contents of hydroxycinnamic derivatives and flavan‐3‐ols in the peel than in the flesh were recorded. However, the content of arbutin was higher in the flesh than in the peel, whereas flavonols were only detected in the peel. In general, hydroxycinnamic derivatives and flavonols were stable throughout storage, but flavan‐3‐ols decreased in concentration under air or CA. Arbutin was the only phenolic compound that increased in concentration as time elapsed. No clear relation was found between the storage conditions tested and the phenolic concentration in pears. Regarding ascorbic acid (AA) and dehydroascorbic acid (DHA), their concentrations were higher in the peel than in the flesh. Furthermore, AA and DHA were strongly affected by storage: the former decreased, whereas the latter increased in content. A decrease in PPO activity was apparent after harvest and during storage, particularly under higher levels of CO 2 . The combination 2 kPa O 2 + 5 kPa CO 2 increased the incidence of internal disorders (viz. brown heart and flesh browning) after storage. Copyright © 2005 Society of Chemical Industry