Saponins from soybeans (Glycine max) were purchased
from Wako Pure Chemical Industries (Japan). Ammonium sulfate was
acquired from AppliChem GmbH (Darmstadt, Germany), ammonia
(≥25%, p.a.) from Carl Roth GmbH & Co. KG (Karlsruhe, Germany) and
acetic acid (p.a) and sulphuric acid (≥95%) from TH Geyer GmbH &
Co. KG (Renningen, Germany)