Cinética de secagem de folhas de manjericão-anis (Ocimum selloi Benth)

Abstract

Ocimum selloi Benth, known as anise basil, stands out for its medicinal and aromatic properties, being widely used in cooking and industry, especially in medicines and cosmetics. Due to its medicinal nature, anise basil has a high-water content in its composition, making it susceptible to degradation during storage. Given the growing cultivation of medicinal plants in Brazil and the need for information on post-harvest processes for the commercial expansion of these species, this study aimed to evaluate the effect of different temperatures and air velocities on the drying kinetics of basil plant leaves-anise. Drying of the leaves occurred under controlled temperature conditions (40, 50, 60 and 70°C) and drying air speeds of 0.4 ms-1and 0.8 ms-1in an experimental fixed-bed dryer. To carry out the experiment, two repetitions were conducted for each drying temperature and air speed, using approximately 40 g in each dryer tray, with intervals of 5 to 30 minutes between weighings. The experimental data on the moisture ratio during drying were subjected to non-linear regression analysis using the Gauss-Newton method to adjust the diffusion model and obtain the effective diffusion coefficient. Among the mathematical models adjusted to predict the drying process of basil-anise leaves, only the Midilli model presented a satisfactory fit in all drying air conditions. With the increase in temperature and air velocity, a reduction in the drying time of the basil-anise leaves was observed. Air temperature had a more significant impact on decreasing drying time, while air velocity showed a more pronounced effect on reducing drying time for air temperature of 40 °C. The values of the effective diffusion coefficient increased with increasing temperature and drying air speed.