Experimental and Modelling Study of Enzymatic Oxidation of 5-o-Caffeoylquinic Acid by Polyphenol Oxidases
| Autor: | Tarcila Bueno dos Santos, David Alexander Mitchell, Nadia Krieger, Vivian Rotuno Moure, Éverton Fernando Zanoelo |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: | |
| Zdroj: | Food Technology and Biotechnology, Vol 48, Iss 4, Pp 548-553 (2010) |
| Druh dokumentu: | article |
| ISSN: | 1330-9862 1334-2606 |
| Popis: | A set of experiments to investigate the enzymatic oxidation of 5-o-caffeoylquinic acid with polyphenol oxidases was carried out in the temperature range from 18 to 39 °C. The kinetic data were obtained in a batch isothermal reactor made of quartz and operated at an optimum pH (approx. 7.0) for enzyme activity, using citrate-phosphate buffer. The decay of 5-o-caffeoylquinic acid concentrations was experimentally monitored with a spectrophotometer at 323 nm. A coefficient of molar absorptivity equal to 1.96·103 mM–1m–1 was found for 5-o-caffeoylquinic acid, based on absorbance measurements with standard aqueous solutions. The kinetic experimental results were used to calculate the parameters Km and vmax of the Michaelis-Menten model, which were 0.24 mM and 2.77·10–4 mM/s at 25 °C, respectively. The effects of temperature on the maximum velocity of oxidation of 5-o-caffeoylquinic acid and on the rate of enzyme deactivation were well described using the Arrhenius equation. |
| Databáze: | Directory of Open Access Journals |
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