Investigations on inulin-type oligosaccharides with regard to HPLC analysis and prospective food applicability

Abstract  

Relevance of research on prebiotic food components is recently largely enhanced as consumption of health-promoting functional foodstuffs displays a definite increase. Since there is a direct correlation between oligomer distribution of inulin and its prebiotic effect, it is of crucial importance to be capable to characterize its actual composition in thermally treated food samples. A newly developed high performance liquid chromatography method is applied for the examination of plant inulin samples using evaporative light scattering detection. The procedure contains a direct detection procedure of native inulin/fructo-oligosaccharide components after dissolving the samples in water at room temperature and by detecting the chain-distribution with HPLC coupled with evaporative light scattering detection. The method is accurate, simple, and without interferences from the detectable signals of mono- and disaccharides as thermal decomposition products of inulin. The analytical procedure eliminates the need to use artificial chemical hydrolysis of the macromolecule. The fructo-oligosaccharide components have been investigated by mass spectrometric detection with APCI ionization. The composition of several industrial samples and the thermal properties of inulin have also been investigated in order to reveal exact composition of inulin comprising bakery products exposed to thermal treatment. The thermal degradation leads to increase of the prebiotic feature as well.