The oil-loaded beads were dried using two drying methods. For
freeze-drying, the beads were placed on drying trays and were
freeze dried under vacuum pressure of 0.015 kPa at a condenser
temperature of −55 ◦C for 24 h. For oven-drying, the beads were
placed on drying trays and were dried in an oven at 70 ◦C until constant
weight was achieved. The beads were placed in a container
that was sealed immediately after drying for future use.