Partially hydrolyzed guar gum characterization and sensitive quantification in food matrices by high performance anion exchange chromatography with pulsed amperometric detection—Validation using accuracy profile

Interest concerning functional ingredients and especially dietary fibres has been growing in recent years. At the same time, the variety of ingredient accepted as dietary fibres and their mixing at low level in complex matrices have considerably complicated their quantitative analysis by approved AOAC methods. These reasons have led to the specific development of an innovative analytical method performed by high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD) to detect and quantify partially hydrolyzed guar gum (PHGG) in fruit preparation and dairy matrices. The analytical methodology was divided in two steps which could be deployed separately or in conjunction. The first, consists in a complete characterization of PHGG by size exclusion chromatography (SEC) with multi-angle light scattering and refractive index detection and HPAEC–PAD to determine its physico-chemical properties and galactomannans content, and the second step is the development of a new HPAEC–PAD method for PHGG direct quantification in complex matrices (dairy product). Validation in terms of detection and quantification limits, linearity of the analytical range, average accuracy (recovery, trueness) and average uncertainty were statistically carried out with accuracy profile. Overall, this new chromatographic method has considerably improved the possibility to quantify without fractionation treatment, low level of dietary fibres emerging from specific galactomannans, in complex matrices and many foodstuffs.

► An innovative methodology using in combination SEC–MALLS and HPAEC–PAD for the characterization of polysaccharides.
► A new chromatographic method, sensitive and reliable, for PHGG direct quantification in complex matrices.
► A validation procedure as realistic as possible with the use of accuracy profile.
► An analytical tool which could further be deployed to other type of low molecular weight polysaccharides.
► A methodology allowing dietary fibres determination when AOAC methods suffer a lack of sensitivity.