Lactic acid was analysed on a Jasco LC-2000 Series
HPLC system (Jasco Inc., Japan) equipped with a Bio-rad Aminex
HPX-87H column (300 7.8 mm i.d., 9 lm particle size), a
CO-2060 PLUS column oven, a PU-2089 pump, an AS 2050 PLUS
autosampler and a MD-2018 Photodiode array detector operated
at 210 nm.