Fresh samples, 0.5–1 kg each of the selected foods (except
Jerusalem artichoke) were randomly purchased from three retailed
shops at Salaya market (as a representative market sold fresh foods
from Southern part of Thailand). A common variety of Jerusalem
artichoke or Kaentawan was randomly collected from Khon Kaen
University Agronomy Farm, Thailand. All food samples were kept
in plastic bags and immediately transferred to the laboratory.
Single composite samples of each food from three retailers were
prepared. The samples, except seeds and nuts, were washed with
tap water until clean, blotted to remove excess water, weighed and
the inedible portion discarded (recorded % edible portion), rinsed
with deionised water once, blotted with clean tissue paper and
then air dried. The remaining edible portion was cut into small size
(