Effect of freezing, drying, and storing dried and frozen onions on its quercetin contents

摘要

In 1996-1999 research has been conducted that tried the influence of drying and freezing processes, and storing dry and frozen onions as well on quercetin contents. Slices 3 mm thick were dried of Rawska, Grabowska, Hyduro F_1 and Armstrong F_1 cultivars. The drying process was conducted in semi-technological drier operating by forced airflow. Dried proaucts were stored in room temperature for one year with quercetin contents being periodically analyzed. Dried product of one cultivar: Rawska, was stored for three years (that received 1996 in due result of initial research). Onions drying and storing process causes very slow its quercetin contents decrease. Three-year storing time of dried onion of Rawska cultivar led to 50% quercetin loss. Airflow freezing of onion cubes and slices, freezing in liquid nitrogen, as well as 6-months storage of the products did not undergo quercetin loss.