Drying processes
Leaves were subject to five different drying methods, i.e., micro-
wave-, oven-, sun-, freeze-, and air-drying. For each drying method,
1 g of fresh leaves was used. In microwave-drying, leaves were
dried in a microwave oven (Sharp R-248E; 800 W) for 4 min.
Oven-drying involved drying for 5 h in an oven (Memmert ULE
500) at 50 ?C. Leaves were sun-dried in the greenhouse for three
days with about 27 h of daylight. Mid-day temperature in the
greenhouse can reach 35 ?C. Leaves were air-dried for three days
in the laboratory at ambient temperature of 25–30 ?C and relative
humidity of 33%. For each of the above drying methods, leaf pieces
were spread out evenly on a Petri dish. In freeze-drying, leaf sam-
ples were lyophilised overnight in a vacuum flask at 0.125 mbar
and ?50 ?C in a freeze-dryer (Christ Alpha 1–4).