Organic acids, contained in the water/
salt-soluble extracts were determined by High Performance Liquid
Chromatography (HPLC), using an ÄKTA Purifier system (GE Healthcare,
Buckinghmshire, UK) equipped with an Aminex HPX-87H column (ion
exclusion, Biorad, Richmond, CA), and an UV detector operating at
210 nm (organic acids and acetoin) or a refractive index detector
(Perkin Elmer 200a) operating at 32 °C (carbohydrates).