Influence of application of microwave energy on quality parameters of mate tea leaves

Polyphenol oxidase and peroxidase are enzymes responsible for browning and quality deterioration in mate tea leaves. The main objective of this work is to investigate the influence of microwave energy on the oxidase activity, moisture content and colour of this raw material. The polyphenol oxidase was inactivated after 30 s of microwave treatment of the samples exposed to high and low light intensity. In samples exposed to low light intensity, the peroxidase activity was reduced for about 60% after 120 s. The exposure of mate tea leaves to microwave energy for 220 s resulted in the moisture content required by the manufacturing process. The measured colour parameters showed that after microwave treatment, mate tea leaves showed a more intense green colour. In a general sense, the results show that the inhibition of polyphenol oxidase and peroxidase by microwave energy have an anti-browning effect on the colour evolution of mate tea leaves. Key words: mate tea leaves, microwave energy, oxidase activity