Artificial drying of Plantago major (plantain) and Justicia pectoralis var. ‘Pectoralis’ (linden)

Abstract

The study characterized the water outflow dynamics during the artificial drying of plantain (Plantago major L.) and linden (Justicia pectoralis J. var. ‘Pectoralis’). The trials were conducted at 40 °C temperature and 50 % relative humidity. The post-harvest flow and the determination of the initial moisture content of each plant were initially established by the gravimetric method. The kinetic characterization was carried out based on the determination of the drying constants and diffusion coefficients of each species. The drying constants were obtained from the mathematical adjustment of five models and the diffusion coefficient was obtained through the analytical solution of Fick’s second law. The best-fitting equation was the Henderson and Pabis equation. That model characterized the moisture loss over time when using a technology with 40 °C temperature and 50 % relative humidity and described the diffusion mechanism occurring in the leaves of the species under study. The drying time of linden is 45 h as opposed to plantain, which takes 77 h, is associated with the few adsorption points with relatively strong bonds that the plant presents. The results constitute a contribution to the knowledge that allows optimizing the drying processes of the species under study in the technological conditions of Cuba.

Keywords

• diffusion
• extraction dynamics
• medicinal plants