Water Mobility in Glassy and Rubbery Solids as Determined by Oxygen-17 Nuclear Magnetic Resonance: Impact on Chemical Stability

Bell, Leonard N.; Bell, Harold M.; Glass, Thomas E.

doi:10.1006/fstl.2001.0807

Cited by 12 publications

(8 citation statements)

References 27 publications

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“…Water mobility was observed in the glassy state of the PVP model system. Moreover, Bell et al [11] reported that water mobility in the food system cannot be used as an indicator to explain the chemical stability of foods. Glass transition temperatures and the physical state of a system are not the only way to clarify complex chemical degradation reactions in food systems.…”

Section: Chemical Stabilitymentioning

confidence: 99%

“…The influence of glass transition temperature on selected chemical reactions is not clear, because water exhibits multiple functions in foods as a plasticizer, solvent, reactant or product of chemical reactions [30]. The analysis of the impact of T g on water mobility and chemical stability of polyvinylpyrrolidone (PVP) by nuclear magnetic resonance indicates that water mobility is not influenced by T g [11]. Water mobility was observed in the glassy state of the PVP model system.…”

Section: Chemical Stabilitymentioning

confidence: 99%

“…A set of theoretical equations (7)(8)(9)(10)(11) was developed to predict the T g 0 and corresponding solids content X s 00 on a state diagram for aqueous solutions of mono-, oligo-and polysaccharides. These are derived from standard glass transition temperatures of anhydrous solids and specific heat changes for mixtures of pure solids and water based on a water clustering model [127].…”

Section: Characterizing the Effects Of Solids Content On Equilibrium mentioning

confidence: 99%

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A Review of Methods, Data and Applications of State Diagrams of Food Systems

2010

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Understanding of the amorphous glassy state of food systems is often crucial in determining physicochemical characteristics and predicting stability of dehydrated and frozen foods. At the glass transition temperature (T g ) of food components, transformation from the amorphous glassy state to the liquid-like rubbery state occurs. T g and ice-melting temperatures (T m ) of food systems are used to construct their state diagrams, in which the different physical states/phases and state/phase transitions of food components are presented in relation to temperature and concentration. A state diagram may be used to identify the appropriate processing and storage conditions of food systems. An overview of determination methods is carried out for glass transition temperature, ice-melting temperature and conditions of maximum-freeze-concentration (glass transition temperature of maximum-freeze-concentrated solution, T g 0 and onset of ice-melting temperature, T m 0 ) for food systems. The data as T g , T m , T g 0 and T m 0 are necessary for construction of state diagrams of foods. The advantages and limitations of the determination methods are discussed. Combined data for glass transition temperature, ice-melting temperature and conditions of maximum-freeze concentration for selected food systems are presented in this study. The effect of food composition on glass line, freezing/melting curve and maximum-freezeconcentration conditions is evaluated. The significance of the state diagrams in predicting the physical, chemical and microbial stability in foods is briefly examined. Glass transition concept and state diagrams are useful for describing the physical and structural stability of food systems at specific conditions, yet they are not considered as the only determining factors of chemical, biochemical and microbial stability of food systems.

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Section: Chemical Stabilitymentioning

confidence: 99%

Section: Chemical Stabilitymentioning

confidence: 99%

Section: Characterizing the Effects Of Solids Content On Equilibrium mentioning

confidence: 99%

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A Review of Methods, Data and Applications of State Diagrams of Food Systems

2010

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“…The effect of water on food chemical stability in solids is multidimensional, being dependent upon the type of reaction and the characteristics of the system. No single explanation for how water affects chemical reactions in reduced moisture solids currently exists (Bell et al 2002). Using 1 H NMR, Partanen et al (2004) studied the plasticization of amylose films by glycerol and water.…”

Section: Water Mobility Conceptmentioning

confidence: 99%

“…Modeling revealed a correlation between denaturation of myosin rods and light chains at $53-58°C and heat-induced changes in myofibrillar water as well as between actin denaturation at $80-82°C and expulsion of water from meat. Bell et al (2002) studied the chemical stability for four chemical reactions in systems with different levels of water mobility as determined by NMR. They emphasized that water mobility was not affected by glass-rubber transition since NMR signals varied differently in different glassy matrices.…”

Section: Water Mobility Conceptmentioning

confidence: 99%