1 PM25 Preparation of PGX-dried gum arabic and its loading with coQ10 by adsorptive precipitation Ricardo Couto a , Emily Wong a , Bernhard Seifried b , Byron Yépez b , Paul Moquin b and Feral Temelli a, * a Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada b CEAPRO Inc., 7824 – 51 Avenue, Edmonton, Alberta T6E 6W2, Canada * feral.temelli@ualberta.ca; Phone: (+1) 780 492 3829; Fax: (+1) 780 492 8914 ABSTRACT The Pressurized Gas eXpanded (PGX) liquid technology was recently developed, operating at mild temperatures (40°C) and moderate pressures (100-200 bar). It allows drying of high molecular weight water-soluble biopolymers, resulting in nano/micro-sized powders of different morphologies, depending on the processing conditions, which is not possible with conventional techniques. The drying medium is a mixture of food grade, recyclable solvents, such as pressurized carbon dioxide (CO2) and anhydrous ethanol (EtOH), forming a so-called PGX liquid. Injecting the aqueous biopolymer solution into a pressurized chamber through a nozzle together with CO2+EtOH (acting as an anti-solvent) results in the precipitation of the biopolymeric structures with large specific surface areas. Once formed, such structures can later be loaded with various bioactives to become novel delivery systems. The objective of this study was to investigate the preparation of PGX-dried gum arabic (GA), a complex mixture of high molecular weight polysaccharides, and its loading by adsorptive precipitation with co-enzyme Q10 (coQ10), a natural lipid-soluble antioxidant. In this second step, SC-CO2 transports solubilized coQ10 to the PGX-dried GA, where adsorption occurs under high pressure, followed by a fast depressurization, forcing coQ10 to precipitate on the surface of the GA. The effects of the concentration of the feed solution, flow rates, and flow rate ratios on the PGX processing of GA were studied. Surface areas ranging from 4.2 to 109.9 m 2 /g were obtained, with lower feed solution concentrations resulting in larger surface areas. The impact of different recirculation flow rates and pressurization rates on the loading efficiency of coQ10 was tested. While the recirculation flow rate did not have an effect, a higher pressurization rate (4.5 vs 1.5 MPa/min) resulted in an increase in the coQ10 loading from 0.6 to 2.0 % (w/w). The PGX drying followed by adsorptive precipitation shows great potential for the development of bioactive delivery systems. INTRODUCTION The Pressurized Gas eXpanded (PGX) liquid technology is a method targeting the drying of high molecular weight water-soluble biopolymers at mild temperatures (40 °C) and moderate pressures (100-200 bar) to avoid the challenges associated with conventional techniques. It is possible to control the types of particle structures generated by controlling the processing conditions. Pressurized carbon dioxide (CO2) and anhydrous ethanol (EtOH) form the PGX liquid,