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Involvement of antioxidant activity in flesh browning of astringent persimmon
- Besada, C., Salvador, A., Vázquez-Gutiérrez, J.L., Herando, I., Pérez-Munuera, I.
- Acta horticulturae 2012 v. no.934 pp. 713-718
- antioxidant activity, astringency, carbon dioxide, catechol oxidase, cell walls, cultivars, intercellular spaces, mechanical damage, microstructure, persimmons, tannins
- Flesh browning caused by mechanical damage is one of the most important disorders during shelf-life of persimmon 'Rojo Brillante', which is an astringent cultivar. Our previous studies have shown that browning manifestation is influenced by the level of astringency of the fruit; the present work studies the implication of polyphenol oxidase activity and total antioxidant capacity. Astringent and non-astringent fruit (fruit submitted to a deastringent treatment of 95% CO2 for 24 h at 20°C) were mechanically damaged and stored at 20°C for 4 days simulating shelf-life period. Mechanical damage caused flesh browning in non-astringent fruit. However, this disorder was not observed in astringent fruit. No differences in PPO activity were observed between astringent and non-astringent fruit. Non-astringent fruit showed much lower antioxidant capacity than astringent fruit. Antioxidant capacity of the fruit seems to play a protective role in the manifestation of flesh browning of persimmon fruit. Microstructure analysis of non-astringent fruit showed the membranes of the flesh tissue affected after deastringency treatment, especially in tannin cells where the precipitation of the tannins occurred. The microstructure of this tissue after shelf-life of mechanically damaged fruit showed degradation of the cell walls and the cellular cements. The observed browning could be related to the precipitated tannins which are found inside the cells or in the intercellular spaces.