Analytical methods
Ethanol and sugars concentrations (melibiose, stachyose, raffinose, sucrose, fructose and glucose) were determined by liquid chromatography (Varian HPLC) equipped with Shodex KS 801 column and IR detector. The temperature of the column oven was set at 80 °C. The standard samples were of 1 g L-1 and 5 g L-1 for all sugars and 1 g L-1, 5 g L-1 and 10 g L-1 for ethanol. The samples injected volume was 15 μL, and water was used as mobile phase. The fermented samples were centrifuged, diluted 5 times and filtered before analysis.