36B-22 |
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A. R. P. Scamparini1, G. C. CENI2, E. M. Baldissera2, C. Dariva2, D. Oliveira2, O. A. C. Antunes3, and E. G. O. Abarzua3. (1) Food Science, UNICAMP, Monteiro Lobato, 80, Campinas/SP, Brazil, (2) Food Engineering, URI - Campus de Erechim, Av. Sete de Setembro 1621, Erechim, Brazil, (3) Biochemistry, Instituto de Química - UFRJ, Rio de Janeiro/RJ, Rio de Janeiro, Brazil Mate (Ilex paraguariensis) is an important natural product of South Brazil. Peroxidase and polyphenol oxidase are the enzymes responsible for browning in mate tea leaves. However, the enzymatic extract can be used in biotechnological processes as catalyst of oxidation reactions. In this context, the objective of this work is to establish an experimental condition that leads to better extraction and measurement of the oxidases activities presented in mate leaves. The results showed that, the mass of raw material and polyvinylpyrrolidone had a positive effect on the process. On the other hand, the pH of measurement of activity had a negative effect for peroxidase and a positive effect for polyphenol oxidase. Related to the stability, the peroxidase presented thermal stability in the temperature range of 20 to 60oC and a residual activity of only 16% after a exposure time of 30 min at 80oC. The activity of polyphenol oxidase was affected by handlings of 20 to 60oC and the enzyme was entirely inactivated when exposed to 6 min at 80oC. The storage at –4 and –80oC did not injure the activity of polyphenol oxidase. The activity of the peroxidase which presented a decrease with freezing and was regenerated after 15th day.
Session 36B, Biotechnology: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |