Palm kernel expeller (PKE) was obtained from a local
palm kernel oil mill for this study. Oligosaccharides
were extracted from raw PKE using water (without enzyme)
as solvent, following the procedure of Chen et al.
(2015). Briefly, one liter of distilled water was added
to 200 g of ground PKE in a one liter Scott bottle,
shaken for 1 h at room temperature and later autoclaved.