Coupling of dielectric and mechanical relaxations with glass transition and stickiness of milk solids

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

“…4 B). The T g values of lactose at 0.11-0.44 a w agreed with previous studies at a w below 0.44 (Potes et al, 2012;Silalai & Roos, 2011). The T g in carbohydrates systems depends upon their composition (Gordon & Taylor, 1952).…”

“…Glass transition temperature (T g ) of pure lactose and lactose-WPI mixtures stored from 0.11 to 0.76 a w (solid square) at 25°C to 45°C (A) and reference T g data (solid circle) fromSilalai and Roos (2011) at room temperature (B) against water content and water activities (0.54-0.76 a w ) using the Gordon-Taylor equation. Data for T g of anhydrous lactose and water were fromPotes et al (2012).…”

The effect of water plasticization and lactose content on flow properties of dairy model solids

“…Moreover, as amorphous solid has a kinetically frozen liquid-like structure and is not in a thermodynamic equilibrium state, amorphous materials exhibit increased molecular mobility and rapidly decreasing viscosity above the glass transition (Roos and Karel, 1991;Champion et al, 2000;Roudaut et al, 2004). Several studies have confirmed that stickiness was controlled by the glass transition (Hennigs et al, 2001;Ozmen and Langrish, 2002;Silalai and Roos, 2011a). Besides, changes in mechanical a-relaxations of milk solids/maltodextrin systems were also associated with powder stickiness, which was also as a result of increasing molecular mobility above the glass transition of powder components (Silalai and Roos, 2011b).…”

Relaxations, Glass Transition and Engineering Properties of Food Solids

“…The sticky point was found for skim milk-milk protein solids systems to occur at increasing temperatures above the T g with rising protein content (Silalai and Roos 2010). The results also showed that although the T g was at an almost constant, a w -dependent temperature, stickiness developed at the higher temperature the higher was the protein content leading to a larger temperature difference between the sticky point and glass transition (Silalai and Roos 2011a). The α-relaxation time corresponding to the sticky point decreased with increasing a w , but there were increases in the temperature difference of the sticky point to T g with increasing a w .…”

“…The α-relaxation time corresponding to the sticky point decreased with increasing a w , but there were increases in the temperature difference of the sticky point to T g with increasing a w . This could be related to a w -dependent interactions of the components in water-plasticised systems and availability of the carbohydrate phase for the formation of liquid bridges at particle surfaces (Silalai and Roos 2011a).…”