Freeze-dried apple
fibre (100 mg) was mixed with 0.1 M NaOH (at a concentration
of 10 mg/ml, under N2), vortexed, acidified to pH 3 with 1 M HCl,
and then extracted with ethyl acetate (1:1) three times. The upper
ethyl acetate fraction was collected after centrifugation (3000g,
5 min). The three ethyl acetate extracts were combined and dried
(under N2).