Kinetic Models for Ultrasound-Assisted Extraction of Water-Soluble Components and Polysaccharides from Medicinal Fungi

The aim of this study was to evaluate the suitable kinetic models for ultrasound-assisted extraction (UAE) of water-soluble constituents and polysaccharides from medicinal fungi. The fungal materials chosen for the study included several important edible/medicinal fungi in both mushroom fruit body and mycelial form. The UAE was performed of powdered fungal material in water at a fixed power and a temperature below 50 °C. The experimental data (extract yields versus time) were fitted to several kinetic models by linear regression. The total extract yields from the two mushrooms exhibited a close fit to the power law, Weibull's exponential, and Elovich's logarithmic model, and that from the fungal mycelia to the parabolic diffusion model. The polysaccharide yields isolated from the mycelial extracts also fitted closely to the parabolic model, but those from the mushroom extracts did not fit well to any of the kinetic models. The results suggested that the UAE kinetics was dependent on the biological form of fungal material and the aggregation/dispersion of solid particles in the extracting solvent. Ultrasound significantly enhanced the extraction of polysaccharides from the fungi without changing their molecular weight profiles.