Viscous fragility of concentrated maltopolymer/sucrose mixtures

Mechanical relaxation times as indicators of stickiness in skim milk–maltodextrin solids systems

“…Miscible polymer mixtures have a single T g between the two T g values of the two components and broadening of the transition is observed as the components become more immiscible (Krause, 1986;. Increasing T g of skim milk-maltodextrin solids systems with increasing maltodextrin contents was in agreement with several studies showing that a higher molecular weight miscible component, e.g., maltodextrin in lactose, was responsible for the higher T g of the blends (Roos and Karel, 1991a Sillick and Gregson, 2009). A significant increase in T g of skim milk-maltodextrin solids systems with increasing maltodextrin content was observed at higher a w (P0.33 a w ), showing high miscibility of the carbohydrate components at higher water contents.…”

“…An increase in maltodextrin content also shifted a-relaxations to higher temperatures. The addition of high molecular weight compounds, such as maltodextrins, could increase stiffness (Frère and Gramain, 1992;Han and Nam, 2002;Sillick and Gregson, 2009) and, thus, reduce molecular mobility of lactose molecules due to a high degree of association as observed from the small magnitudes of modulus changes. This was consistent with our previous study (Silalai and Roos, 2010b) revealing the reduced molecular mobility of high protein-content skim milk solids systems.…”

“…Amorphous low molecular weight sugars, such as mono-and disaccharides, are hygroscopic and show glass transitions at low temperatures (Levine and Slade, 1986;Roos, 1993;Seo et al, 2006). Mixing a low-molecular-weight solvent with a glass-forming polymer leads to a depression of the T g (Roos and Karel, 1991a;Sillick and Gregson, 2009). Effects of miscible food components on the overall glass transition can be derived from their individual T g (Gordon and Taylor, 1952;Couchman and Karasz, 1978;Roos and Karel, 1991a;.…”

“…Glass transition and viscosity of mixtures of amorphous components are often the two key physico-chemical parameters characterizing properties of food materials (Angell et al, 1982;Levine and Slade, 1986;Borde et al, 2002;Avaltroni et al, 2004;Sillick and Gregson, 2009). Glass transition reflects the molecular mobility in formulations with miscible components, and it can be measured from changes in material characteristics Blanshard, 1992, 1993;Roudaut et al, 2004).…”

X-ray diffraction analysis of lactose crystallization in freeze-dried lactose–whey protein systems

“…Previous studies showed that crystallization of amorphous sugars could be delayed by the presence of other sugars or impurities, i.e. starch (Iglesias & Chirife, 1978), corn syrup solids (Gabarra & Hartel, 1998), trehalose (Mazzobre, Soto, Aguilera, & Buera, 2001), proteins (Sillick & Gregson, 2009), and maltodextrins (Potes, Kerry, & Roos, 2012).…”