title: Influence of DE-value on the physicochemical properties of maltodextrin for melt extrusion processes.
abstract: In this study, five different types of maltodextrins (DE-2, DE-6, DE-12, DE-17 and DE-19) were characterized for the physico-chemical properties. TGA, DVS and SEC analyses were carried out and additionally apparent melt-viscosity (in a micro-extruder) and the glass transition temperature (analyzed by DMA) of maltodextrin/plasticizer mixtures were also measured in order to evaluate both the effect of plasticizer nature and content and the effect of the DE-value. For this, three plasticizing agents were compared: water, d-sorbitol and glycerin. The adsorption isotherms showed that depending on the DE-value and the relative humidity they were exposed to, different behavior could be obtained. For example, for relative humidities below 60% RH maltodextrin DE-2 was the least hygroscopic. And on the contrary for relative humidities above 75% RH maltodextrin DE-2 was the most hygroscopic. The rheology measurements showed that the viscosity decreased with the increase of the DE-value and with the plasticizer content, as expected. On the contrary, no direct correlation could be established between the DE-value and the glass transition temperature. These results demonstrated that to predict maltodextrins behavior and to better adapt the process conditions, combined analyses are mandatory as the DE-value alone is not sufficient. The most compelling evidence was obtained by size exclusion chromatography, which pointed out that maltodextrins had a bimodal molecular weight distribution composed of high and low molecular weight oligo-saccharides. Indeed, maltodextrins are highly polydisperse materials (i.e. polydispersity index ranging from 5 to 12) and that should be the reason why such distinct behaviors were observed in some of the physico-chemical analyses that were preformed.
authors.affiliation: Université de Toulouse, INP-ENSIACET, LCA (Laboratoire de Chimie Agro-industrielle), F-31030 Toulouse, France; INRA, UMR-1010-CAI, F-31030 Toulouse, France.
authors.forename: Natalia
authors.initials: N
authors.lastname: Castro
authors.affiliation: Université de Toulouse, INP-ENSIACET, LCA (Laboratoire de Chimie Agro-industrielle), F-31030 Toulouse, France; INRA, UMR-1010-CAI, F-31030 Toulouse, France.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Durrieu
authors.affiliation: Université de Toulouse, INP-ENSIACET, LCA (Laboratoire de Chimie Agro-industrielle), F-31030 Toulouse, France; INRA, UMR-1010-CAI, F-31030 Toulouse, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Raynaud
authors.affiliation: Université de Toulouse, INP-ENSIACET, LCA (Laboratoire de Chimie Agro-industrielle), F-31030 Toulouse, France; INRA, UMR-1010-CAI, F-31030 Toulouse, France. Electronic address: Antoine.rouilly@ensiacet.fr.
authors.forename: Antoine
authors.initials: A
authors.lastname: Rouilly
mesh_terms: D055598:Chemical Phenomena; D008970:Molecular Weight; D011134:Polysaccharides / Q000737:chemistry*; D012212:Rheology; D044366:Transition Temperature; D014783:Viscosity
chemical_list: D011134:Polysaccharides; C008315:maltodextrin
keywords: Apparent viscosity; Dextrose equivalent value; Glass transition temperature; Maltodextrins; Molecular weight distribution; Water sorption isotherm