The PPO activity in raw and boiled Jerusalem artichoke tubers,
was determined using an adjusted procedure of Joshi, Rupasinghe,
and Khanizadeh (2007). Enzyme extracts were prepared from
500 mg of freeze-dried material by addition of 10 ml cold extraction
solution (2% wt/vol PVPP in sodium phosphate buffer
(pH = 6.5)) and immediately centrifuged at 4 C at 1277g for 15 min