2.6. Phenolic acids
The content of phenolic acids was determined by high-performance
liquid chromatography (HPLC). Phenolic acids were extracted
from 500 mg freeze-dried material of raw and boiled
Jerusalem artichoke tubers with 15 ml of an extraction solution
(1.2 M HCl in 50% MeOH) for 16 h at 35 C. The extracts were then
centrifuged at 1277g for 15 min. The supernatants were evaporated
to dryness under reduced pressure, and made up to a total
volume of 1.5 ml with HPLC-grade MeOH.