Myrtle Leaves (<i>Myrtus communis</i> L) and Olive Leaves (<i>Olea europaea</i>): Effect of Drying by Fluidization and Solar Methods on Key Bioactive Compounds Contents

Abstract

The present study aimed to evaluate the influence of drying by fluidization technology, compared to a traditional solar drying, on phenolic compounds of Moroccan Myrtus communis L. and Olea europaea L. species. Two main parameters of drying by fluidization (air speed (0.3-1 m/s for myrtle leaves and 1-3 m/s for olive leaves) and air temperature (40-60 °C for the two plants leaves)) were modified and controlled. Results showed that high loss values in total polyphenols (TPP) and flavonoids (TF) were observed at (60 °C; 0.3 m/s) for myrtle leaves and at (60 °C; 1 m/s) for olive leaves. However, these compounds were more stable at (40 °C; 1 m/s) for myrtle leaves and at (40 °C; 3 m/s) for olive leaves. Regarding the solar drying method, the results showed that, for myrtle leaves, high losses were observed in the TPP and TF contents, compared to the fluidization method for all processing parameters. For olive leaves, traditional solar drying gives products with phenolic contents similar to those obtained by fluidization drying, especially at (60 °C; 3 m/s). The findings indicated that employing the fluidization drying method might be a suitable approach for enhancing the conservation of bioactive compounds within myrtle and olive leaves.