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

Pectobacterium atrosepticum, P. carotovorum subsp. brasiliensis, and Dickeya spp. cause soft rot of potato (Solanum tuberosum) worldwide. Plants respond to bacterial invasion by activating defense responses associated with accumulation of several enzymes and inhibitors, which prevent pathogen infection. This study focused on the role of polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL), chlorogenic acid, and total soluble phenols in imparting resistance to soft rot pathogens. Seven and 11 varieties grown by farmers in South Africa and Zimbabwe, respectively, were used in the study. The results showed significantly higher (P < 0.001) enzyme activity of PPO and PAL as well as higher concentrations of chlorogenic acid and total soluble phenols in Vanderplank, Pentland Dell, M69/11, Romano, M59/20, and MondialZw. PAL activity increased significantly with time in all varieties, and the highest activity was recorded 8 h after cutting. The resistance of the varieties was correlated with high PPO and PAL enzyme activity as well as increased concentrations of chlorogenic acid and total soluble phenols. PPO, POD, and PAL activities increased significantly in wounded and inoculated tubers. These findings show that PAL, PPO, POD, chlorogenic acid, and total soluble phenols play a role in imparting resistance to potato soft rot infection.

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Cultivar and seasonal variation in bioactive compounds of highbush blueberry fruits (Vaccinium corymbosum L.)

Folia Horticulturae ◽

10.2478/fhort-2013-0148 ◽

2010 ◽

Vol 22 (1) ◽

pp. 31-35 ◽

Cited By ~ 4

Author(s):

Barbara Łata ◽

Marzena Wińska-Krysiak

Keyword(s):

Enzyme Activity ◽

Seasonal Variation ◽

Chlorogenic Acid ◽

Bioactive Compounds ◽

Growing Season ◽

Vaccinium Corymbosum ◽

Seasonal Effect ◽

Highbush Blueberry ◽

Glutathione System ◽

Huge Impact

Abstract Seasonal and cultivar variations of the phenolic, thiol, and ascorbate compound contents as well as the antioxidative enzyme activity in six cultivars of highbush blueberry were investigated. Berries of the ‘Earlyblue’, ‘Patriot’, ‘Bluecrop’, ‘Duke’, ‘Darrow’ and ‘Lateblue’ cultivars were sampled in 2005 and 2006. Chlorogenic acid, (-)-epicatechins, and ascorbate contents and CAT activity were found to be at the lowest degree affected by growing season conditions. ‘Seasonal effect’ had, however, a huge impact on the GR activity, as well as L-cysteine and glutathione content, suggesting that the glutathione system was highly influenced through growing factors in blueberry fruit. Berries of ‘Earlyblue’ were the richest source of antioxidants, at the same time revealing their quite stable quantity over the examined years. The second highest in bioactive stability was ‘Duke’, classified as medium with respect to antioxidant content.

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