Characterization and quantitation of short-chain fructooligosaccharides and inulooligosaccharides in fermented milks by high-performance anion-exchange chromatography with pulsed amperometric detection.

With the increased interest in the possible link between fructooligosaccharides (FOS) intake from functional foods and health, the need for reliable data on the individual FOS content of those foods has become very important. In this study a new high-performance anion-exchange chromatography coupled to pulsed amperometric detection (HPAEC-PAD) method is described for the selective determination of short-chain FOS and inulooligosaccharides (IOS) present in the investigated prebiotic food ingredients. Response factor of PAD was investigated in relationship with degree of polymerization and isomers. The developed HPAEC-PAD method has been applied to characterize short-chain oligosaccharides of the inulin series with DP ranging from DP3 to DP7 and IOS from DP2 to DP7. Their quantification in commercial water-soluble fibers of relevant importance as prebiotic food ingredient added in fermented milks has been performed. In order to evaluate the reliability of the proposed method, results have been compared with those obtained by the official enzymatic method. Furthermore, this new HPAEC-PAD method may contribute to clarify the real importance, prebiotic effectiveness and biological role of these carbohydrates.