A critical review of some non-equilibrium situations and glass transitions on water activity values of foods in the microbiological growth range

Chirife, Jorge; Buera, M. Pilar

doi:10.1016/0260-8774(94)00033-6

Cited by 46 publications

(14 citation statements)

References 62 publications

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“…As can be seen, although both models give acceptable approximations to experimental data, the new model follows the sigmoid relationship between Tg and a w more closely. Many authors have previously reported this sigmoid relationship (Roos 1995d;Chirife and Buera 1995;Roos and Karel 1991c). In addition to the graphical comparison given in Fig.…”

Section: Resultsmentioning

confidence: 66%

Mathematical Model for Prediction of Glass Transition Temperature of Fruit Powders

Khalloufi¹,

El-Maslouhi²,

Ratti³

2000

Journal of Food Science

113

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Glass transition temperature (Tg) has been identified as a critical factor to predict quality of foodstuffs during processing or storage. Differential Scanning Calorimetry (DSC) was used to determine the Tg of 4 types of berry powders as a function of water content, and equilibrium moisture content was measured over different saturated solutions using the gravimetric method. The Guggenheim-Anderson-deBoer model was used to predict water activity (a w ). Four models were tested for their ability to predict Tg as a function of the solid fraction. The combined effects of Tg and a w were incorporated into a new mathematical expression. The expression requires the determination of Tg (dry solids) of the product and data on equilibrium moisture sorption. The mean percent error of the model predictions is less than 3.6% when compared to experimental data.

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Section: Resultsmentioning

confidence: 66%

Mathematical Model for Prediction of Glass Transition Temperature of Fruit Powders

Khalloufi¹,

El-Maslouhi²,

Ratti³

2000

Journal of Food Science

113

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“…Water plays a role of plasticizer (Chang et al, 2000;Chirife & Buera, 1995;Li, Kloeppel, & Hsieh, 1998;Roos, 1995;Slade & Levine, 1995). Transformation glass-rubber causes dissipation of elastic energy and relaxation of stresses, hence possibility of fragile breaks is reduced substantially (Poliszko et al, 1995).…”

Section: Discussionmentioning

confidence: 98%

Antiplasticization of cereal-based products by water. Part II: Breakfast cereals

Gondek

Lewicki

2006

Journal of Food Engineering

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“…However, in many cases, the glass transition concept alone does not predict shelf‐life stability very well. Much experimental evidence does not support a clear correlation between T g and microbial activity (Chirife and Buera 1994, 1995, 1996; Buera and others 1998; Vittadini and Chinachoti 2003). Similarly, many investigations show that glass transition alone cannot explain enzymatic and nonenzymatic activities below T g .…”

Section: Introductionmentioning

confidence: 99%

NMR State Diagram Concept

Lin

Ruan

Chen

et al. 2006

Journal of Food Science

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This article introduces a new concept, the NMR (nuclear magnetic resonance) state diagram, in the context of food shelf-life stability as affected by the molecular mobility of the food matrix. Our literature review shows that some shelf-life-related changes cannot be explained or predicted by the current a w and glass transition temperature concepts. This article presents the theoretical principles and some experimental evidence of the NMR state diagram concept that could be complementary to the a w and glass transition concepts. An NMR state diagram is a curve of NMR relaxation time versus temperature. Some of the curve features were found to correlate highly to the physiochemical states and changes of food polymers, for example, caking, stickiness, and firming. The potential applications of this concept in quality and safety of food products, especially dry and intermediate moist foods, may include ingredients screening, prediction of physiochemical changes, chemical degradation, and microbiological activity. The goal concept of this article is to provoke more in-depth studies to analyze the relationships among NMR relaxation, molecular mobility, and stability of foods.

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A critical review of some non-equilibrium situations and glass transitions on water activity values of foods in the microbiological growth range

Cited by 46 publications

References 62 publications

Mathematical Model for Prediction of Glass Transition Temperature of Fruit Powders

Mathematical Model for Prediction of Glass Transition Temperature of Fruit Powders

Antiplasticization of cereal-based products by water. Part II: Breakfast cereals

NMR State Diagram Concept

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