| Popis: |
Summary Leaves of erva-mate (Ilex paraguariensis St. Hill) were heat treated with different combinations of time and temperature. Polyphenol oxidase (PPO) and peroxidase (POD) residual activities and colouring (L, a, b and ΔE) were studied after treatment for 3 weeks. The best results for enzyme inactivation after heat treatment were obtained with the leaves treated at 450 °C for 15 s and at 500 °C for 10 s, with reductions of 90.6% and 83.4% for PPO and 94.5% and 92.7% for POD. These groups also showed low levels of enzyme activity during the first few days of storage, and a few days later no enzyme activity was detected. The data on the colours, specially –a values (green colour), were in accordance with results for enzyme activity and helped in the research on the changes that occur in the leaves during storage. Data from this work can be suggested for the improvement of the current method of erva-mate processing, which is still performed empirically. |
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