The ethanol concentrations in the samples were analyzed using
a gas chromatography (GC-17A, Shimadzu, Kyoto, Japan) with a
flame ionization detector. A WAX-10 capillary column (length
30 m 0.25 mm ID, film thickness 0.25 mm; Supelco, USA) was used
with helium as the carrier gas at a flow rate of 1.0 ml/min.