The edible portion of each set
was prepared and separately homogenised (Ace homogenizer, NISSEI
Ltd., Tokyo, Japan) in a dark room at 25 C. Approximately 500 g
of each of homogenised samples were pooled and re-homogenised
to obtain a single, uniform composite sample.Samples from the
other five provinces were treated similarly. Thus a total of six
composite samples were obtained for each vegetable or fruit.