Thermal inactivation of peroxidase and polyphenoloxidase enzymes in mate leaves (Ilex paraguariensis) in a conveyor belt oven

Abstract

The inactivation of oxide reductases in mate leaves, a process known in Brazil as sapeco, is carried out at temperatures of 400 to 620°C. High temperatures can produce pyrolysis compounds, such as polycyclic aromatic hydrocarbons. In this study, the time/temperature binomial was determined for the inactivation of peroxidase (POD) in mate in a conveyor belt oven. POD showed greater thermal resistance than polyphenoloxidase. A 22 full factorial design (levels +1 and - 1), with two axial points (levels -α and +α) and three central points (level zero), was used. The biphasic and consecutive step models showed the best fit to the data obtained for the inactivation of POD (R2 = 0.99). The best inactivation was obtained after treatment at 255°C for 20 to 24 s, achieving a green colour the same as that obtained through processing using the traditional procedure.