Extraction and Micronization of β-glucan in One-step Process by Combining Subcritical Water and Supercritical Carbon Dioxide

Subcritical water extraction was recognized as a one of the green ways to isolate plant biomass constituents. In this work, water at subcritical conditions would be subjected as a medium to isolate β-glucans from barley (Hordeum vulgare L.) and Ganoderma lucidum (G. lucidum). The experiment would be performed at 130-190 °C and 4-40 MPa in a semi batch process. The FT-IR spectra described that, at subcritical water conditions, β-glucan was removed from barley grains and G. lucidum via dehydration and decarboxylation. To enhance the separation process, supercritical carbon dioxide (CO2) is injected. To keep and to concentrate the water soluble glucan compounds in the liquid extract product, the micronization technique was performed integratedly after extraction process. SEM image illustrated that the particle generated was shriveled or dimpled and spherical with size from 1 to 6 μm, and the β-glucans content in the particle product is around 40 to 45 wt%.