Polymer‐Water Interaction of Maltodextrins. Part III: Non‐freezable Water in Maltodextrin Solutions and Gels

Abstract

The non-freezability of a portion of the water in maltodextrin solutions and gels was taken as a measure for polymer-water interactions. The amount of non-freezable water was determined by measuring the melting enthalpy of freezable water in dependence on polymer concentration by means of DSC. The amount of non-freezable water or the water binding capacity of the maltodextrins depends on their mean molecular mass and distribution of molecular masses. The higher the P, the higher is the amount of non-freezable water at high polymer concentrations. The aggregation of polysaccharide molecules does not change the amount of non-freezable water. The gelation in connection with phase separation effects only a weak change in the mobility of free freezable water. Overriding and accidenthl physical and chemical variables of influence are discussed with respect to the totality of polymer-water interactions in maltodextrins. Polymer-Wasser-Wechselwirkungen von Maltodextrinen. Teil 3: Nichtgefrierbares Wasser in Maltodextrinlosungen und -gelen. Als Kriterium fur Polymer-Wasser-Wechselwirkungen der Maltodextrine wurde die Nichtgefrierbarkeit eines Teils des Wassers in Maltodextrinlosungen und Gelen herangezogen Der Anteil an nichtgefrierbarem Wasser wurde mit Hilfe der DSC-rechnik durch Messung der Schmelzenthalpie des in Abhangigkeit voii der Polymerkonzentration gefrierbaren Wassers bestimmt. Der Ante\l an nichtgefrierbarem Wasser bzw. die Wasserbindungskapazitat der Maltodextrine wird durch ihre Molmasse und Molmassenverteilung bestimmt. Je groBer der P, ist, desto hoher ist der Anteil an nichtgefrierbarem Wasser bei hohen Polymerkonzentrationen. Durch Aggregation der Polysaccharidmolekule wird der Anteil an nichtgefrierbarem Wasser nicht verandert. Die mit der Gelbildung verbundene Phasentrennung fuhrt lediglich zu einer schwachen Differenzierung des freien gefrierbaren Wassers. Die physikalischen und chemischen EinfluRgroRen der Polymer-Wasser-Wechselwirkungen von Maltodextrinen werden im Uberblick diskutiert und nach ihrer Bedeutung gewichtet. 142 starchlstarke 42 (1990) Nr. 4, S . 142-147 0 VCH Verlagsgesellschaft mbH, D-6940 Weinheim, 1990 0038-9056/90/0404-0142$02.50/0 starchlstarke 42 (1990) Nr. 4, S. 142-147 cleavage (hydrolytic) point [l-31. They show that the amylasecatalyzed reaction for maltohexaose Gg as a substrate produces glucose (G) in the highest probability, that is, probabilities of the production of maltosaccharides from G6 are 75% for Gs and G, 14% for G4 and G2, and 11% for G3 and Gs. Probabilities of glucose production from maltopentaose G5 and maltotetraose ~~~~~~ ~ ~ starchktllrke 42 (1990) Nr. 4, S. 147-151 8 VCH Verlagsgesellschaft mbH, D-6940 Weinheim, 1990 OO38-9O56/9o/wo4M47$02.50/0

Proton NMR Relaxometry as a Useful Tool to Evaluate Swelling Processes in Peat Soils~!2009-07-26~!2009-12-04~!2010-06-15~!

“…The results of the two repetition samples or replicates (RS1 and RS2) are displayed. The amounts of non-freezable water were comparable to those reported for different starch materials [15] or peats [7], but were larger than those reported by Schaumann et al [14]. Increasing amounts of non-freezable water during hydration were also found for starch gels [52].…”

“…According to the findings for maltodextrin gels [15], it can be suggested that the melting peak splitting of water in peat was due to the entrapment of water in a gel phase. By interpreting the energy transformation related with the sharp peak as quantitative measure for the amount of water in gels, the water contents related to the sharp peak at the beginning and end of hydration (Table 3) indicated the formation of new and/or the change of existing gel phases during hydration.…”

“…They are broader and split into two or more overlaying peaks. Radosta and Schierbaum found a splitting of the melting peak of water only in maltodextrin gels, but not in maltodextrin solutions, although the determined amounts of non-freezable water were comparable for both systems [15,17]. Consequently, they attributed the melting peak splitting to the entrapment of water within the gel matrix.…”

“…DSC was used to study the melting and freezing behaviour of water and to calculate the amounts of non-freezable and freezable water in hydrogels [15,16] or peat soil samples [7,14]. The melting of freezable water in moist samples is characterised by endothermic water melting peaks in the DSC thermograms, which originate from the additional energy uptake of the melting process.…”

Heat stability and freeze–thaw stability of oil-in-water emulsions stabilised by sodium caseinate–maltodextrin conjugates

“…On freezing of the emulsions, Md free in the aqueous phases would have become more concentrated in the unfrozen aqueous phase of all the emulsions and this may have eventually led to sufficient differences in levels of Md that would have led to differences in freezing temperature depression and thus slight differences in levels of unfrozen water in the aqueous phases of the different emulsions (Chronakis, 1998;Radosta & Schierbaum, 1990). Also, because of Md hydration, the level of water remaining unfrozen in the aqueous phases of the emulsions would increase with increasing concentrations of Md free in the aqueous phase of the emulsions (Chronakis, 1998).…”