Dielectric properties of frozen maltodextrin solutions with added NaCl across the glass transition

Abstract

The change in the dielectric properties of frozen 200 g kg −1 maltodextrin solutions upon warming has been recorded using a capacitance meter and a dielectric thermal analysis instrument. The capacitance and permittivity increased by several orders of magnitude after melting, and higher values were obtained at a higher measurement frequency or with added NaCl, while a marked increase (labelled T rise ) was seen close to the glass transition temperatures measured by differential scanning calorimetry. The transition temperatures shifted to more negative values by 4-6 • C upon the addition of 0.1 mol kg −1 NaCl, consistent with the freezing point depression of the freeze-concentrated solutions. INTRODUCTIONMaltodextrins are produced by the controlled hydrolysis of starch to generate a mixture of oligosaccharides of α-D-glucose of varying chain lengths. 1 They are classified by their dextrose equivalence (DE), a measure of total reducing sugars compared to glucose with a value of 100, which is related to the average molecular weight (M n ) as follows:

Effects of lipids on the water sorption, glass transition and structural strength of carbohydrate-protein systems

“…Changes in mechanical and electric properties during these processes around T g result in α-relaxation which can be detected by dynamic mechanical (DMA) and dielectric (DEA) analyses in a multi-frequency mode. These methods are suitable for many carbohydrates with different water contents (Ermolina, Polygalov, Bland, & Smith, 2007;Kilmartin, Reid, & Samson, 2004;Potes, Kerry, & Roos, 2012;Silalai & Roos, 2011). For amorphous powders, the structural relaxation time can be calculated from frequency of primary α-relaxation (Noel, Parker, & Ring, 2000).…”

Microencapsulation by Freeze-Drying of Potassium Norbixinate and Curcumin with Maltodextrin: Stability, Solubility, and Food Application

“…They are classified by their dextrose equivalent (DE) and due to physicochemical properties and low cost are widely used in the food industry. Both hydrophilic and hydrophobic components can be microencapsulated with maltodextrins. − …”