Selected fructooligosaccharide (1-kestose, nystose, and 1(F)-beta-fructofuranosylnystose) composition of foods and feeds

Fructooligosaccharides (FOS) are naturally occurring sugars with potentially beneficial nutritional effects. They are widely distributed throughout the plant kingdom. An ion chromatographic method was developed to rapidly and accurately measure FOS in selected food and feed ingredients ingested by humans and animals. The objective of this study was to determine the 1-kestose (1-kestotriose; GF(2)), nystose (1,1-kestotetraose; GF(3)), and 1(F)-beta-fructofuranosylnystose (1,1,1-kestopentaose; GF(4)) content of a wide variety of foods and feedstuffs. After extraction with water and appropriate filtration, samples were chromatographed, using an alkaline sodium acetate gradient, through an ion exchange column and guard fitted to a Dionex chromatography unit equipped with a pulsed electrochemical detector. All samples were prepared both with and without spikes of standards to verify recovery and peak identification. Samples of the Compositae family were highest in total FOS followed by Allium species of the Amaryllidadeae family. The method provided excellent separation, recovery, and quantification of the GF(n) units of FOS. Accurate quantitation of FOS will allow more precise nutritional formulations to be developed with respect to inclusion of this functional food component in human and animal diets.