https://onlinelibrary.wiley.com/doi/pdf/10.1021/js9601896

Characteristics and Significance of the Amorphous State in Pharmaceutical Systems

Water, the most abundant constituent of natural foods, is a ubiquitous plasticizer of most natural and fabricated food ingredients and products. Many of the new concepts and developments in modern food science and technology revolve around the role of water, and its manipulation, in food manufacturing, processing, and preservation. This article reviews the effects of water, as a near-universal solvent and plasticizer, on the behavior of polymeric (as well as oligomeric and monomeric) food materials and systems, with emphasis on the impact of water content (in terms of increasing system mobility and eventual water "availability") on food quality, safety, stability, and technological performance. This review describes a new perspective on moisture management, an old and established discipline now evolving to a theoretical basis of fundamental structure-property principles from the field of synthetic polymer science, including the innovative concepts of "water dynamics" and "glass dynamics". These integrated concepts focus on the non-equilibrium nature of all "real world" food products and processes, and stress the importance to successful moisture management of the maintenance of food systems in kinetically metastable, dynamically constrained glassy states rather than equilibrium thermodynamic phases. The understanding derived from this "food polymer science" approach to water relationships in foods has led to new insights and advances beyond the limited applicability of traditional concepts involving water activity. This article is neither a conventional nor comprehensive review of water activity, but rather a critical overview that presents and discusses current, usable information on moisture management theory, research, and practice applicable to food systems covering the broadest ranges of moisture content and processing/storage temperature conditions.

Beyond water activity: recent advances based on an alternative approach to the assessment of food quality and safety

The field of enthalpy relaxation is reviewed. Current phenomenologies for dealing with the non-linear and non-exponential character of enthalpy relaxation are presented, and their successes and shortcomings are discussed. Qualitative experimental data and quantitative parameterizations are summarized, and some directions for future research are suggested.

Enthalpy relaxation and recovery in amorphous materials

Physical aging of polymers

M.J. Richardson

Papers

Derivation of accurate glass transition temperatures by differential scanning calorimetry

Volumetric properties of polystyrene: influence of temperature, molecular weight and thermal treatment

Factors influencing the glass transition of DGEBA-anhydride epoxy resins

Enthalpy changes in molten n-alkanes and polyethylene

The glass transition behaviour and thermodynamic properties of amorphous polystyrene