Kinetic modelling of total phenolic compounds from Ilex paraguariensis (St. Hil.) leaves: Conventional and ultrasound assisted extraction

In this paper, we compared ultrasound-assisted extraction (UAE) and conventional ex-traction by agitation (AE) for total phenolic compounds (TPC) extraction from yerba mate leaves (Ilex paraguariensis St. Hil). Water and 50% aqueous ethanol solution were used as solvent and the effect of solvent-to-solid ratio, particle size, stirring speed (AE) and ul-trasound power amplitude (UAE) was examined. Two kinetic models (i.e. Peleg model and swelling / diffusion model) have been introduced to describe the kinetics of TPC extrac-tion. The experimental data were adequately fitted by swelling/diffusion model (R2 > 0.98; EP < 10%; RMSE < 0.24) that considers two mechanisms coupled at different rates. The initial extraction rate increased at a higher volume of solvent (10 ml/g), smaller particle size (0.297 mm) higher ultrasound power amplitude (100%) and the use of 50% aqueous ethanol solution. Maximum equilibrium TPC concentration was observed with the sy-nergic effect of 50% aqueous ethanol solution and the higher power amplitude (15,0 g GAE/ 100 g dm). This work would provide more information on the extraction mechanisms that occur in the microstructure of yerba mate leaves for the industrial production of TPC. (c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study compared ultrasound-assisted extraction (UAE) and conventional extraction by agitation (AE) for total phenolic compounds (TPC) extraction from yerba mate leaves. Water and 50% aqueous ethanol solution were used as solvents, and the effects of solvent-to-solid ratio, particle size, stirring speed (AE), and ultrasound power amplitude (UAE) were examined. The experimental data were fitted well by the swelling/diffusion model, which considers two mechanisms coupled at different rates. The results provide valuable information for the industrial production of TPC from yerba mate leaves.