Influence of DE-value on the physicochemical properties of maltodextrin for melt extrusion processes. (25th June 2016)

• Record Type: Journal Article
• Authors: Castro, Natalia; Durrieu, Vanessa; Raynaud, Christine; Rouilly, Antoine
• Is Part Of: Carbohydrate polymers. Volume 144(2016)
• Page Start: 464
• Page End: 473
• Publication Date: 2016-06-25
• Subjects: Maltodextrins -- Dextrose equivalent value -- Apparent viscosity -- Glass transition temperature -- Water sorption isotherm -- Molecular weight distribution; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2016.03.004
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Maltodextrins are highly polydisperse materials and present a bimodal molecular weight distribution as determined by SEC. Melt viscosity of maltodextrins decreases with the increase of DE-value whatever the plasticizer. Influence of the DE on glass transition temperature is not linear and differs according to the nature of the plasticizer. The hygroscopic behaviour of maltodextrins is complicated and the DE-value alone is not sufficient to explain it. 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.