Prebiotic ingredients of prebiotics (or those that boost the growth of beneficial probiotic bacteria in the gut) are derived from insoluble fibres and oligosaccharides which can be incorporated into a wider variety of end products than probiotic bacteria.

Portuguese scientists have been able to extract non-digestible oligosaccharides with prebiotic activity from corn cobs by using a technique called autohydrolysis.

The researchers, from Lisbon's National Institute of Engineering and the Higher Institute of Agriculture, degraded hemicellulose in the corn to selective release soluble oligomeric structures xylo-oligosaccharides (XOS). The prebiotic activity of two fractions with average degrees of polymerization (DP) of 3-4 and 5-6 were compared with commercial XOS (Xylo-Oligo95P, Suntory, Japan).

Moura and co-workers then tested the ability of these oligosaccharides (mainly xylotriose and xylotetraose) to promote the growth of selected gut bacteria, including Bifidobacterium adolescentis, B. longum, Lactobacillus brevis and L. fermentum.

It was found that B. adolescentis and L. brevis displayed the highest growth and XOS consumption, while growth of B. longum and L. fermentum was low.

The procedure above has been described in the August 2007 issue of LWT - Food Science and Technology.

Find more details from the full report.