Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2005
Publication Date: 10/1/2005
Citation: Manderson, K., Pinart, M., Tuohy, K.M., Grace, W.E., Hotchkiss, A.T., Widmer, W.W., Yadav, M.P., Gibson, G.R., Rastall, R.A. 2005. In vitro determination of the prebiotic properties of oligosaccharides derived from an orange juice manufacture byproduct stream. Applied and Environmental Microbiology. 71:8383-8389. Interpretive Summary: The enormous volume of fruit and vegetable processing residues, such as orange peels and sugar beet pulp, represents an underutilized domestic resource of valuable health-promoting compounds. These residues have been used as cattle feed components, but as such their value is low (< 5 cents/pound) and there is more supply than demand for cattle feed. However, these residues are rich in valuable carbohydrates. Prebiotics are carbohydrates that are selectively fermented by gut bacteria which provide health benefits to people who consume them. New sources of inexpensive prebiotics are needed to supply the growing demand created by increasingly health-conscious consumers. We demonstrated, for the first time, that carbohydrates derived from pectin found in orange peel have prebiotic properties. A method was developed to produce these prebiotic carbohydrates from a by-product stream of orange juice processing. Orange peel is an inexpensive source of health-promoting prebiotics that can be used as functional food and animal feed ingredients. Development of these prebiotics into commercial products will add value to citrus processing residues and will benefit citrus growers and processors.
Technical Abstract: The fermentation properties of oligosaccharides derived from orange peel pectin were assessed in mixed faecal bacterial culture. The orange peel oligosaccharide fraction contained glucose in addition to rhamnogalacturonan and xylogalacturonan pectic oligosaccharides. Temperature and pH-controlled, stirred anaerobic faecal batch cultures were used and fermentation end products, bacterial populations and subsequently a prebiotic index (PI) were all determined. Pectic-oligosaccharides (POS) were able to increase numbers of bifidobacteria and eubacteria, albeit resulting in a lower prebiotic index than did fructo-oligosaccharide (FOS) metabolism. Orange albedo maintained the growth of most bacterial populations and gave a similar PI to soluble starch. Fermentation of POS resulted in an increase in the number of eubacteria and concomitantly increased butyrate production.