THE GLASSY STATE PHENOMENON IN APPLICATIONS FOR THE FOOD-INDUSTRY - APPLICATION OF THE FOOD POLYMER SCIENCE APPROACH TO STRUCTURE-FUNCTION-RELATIONSHIPS OF SUCROSE IN COOKIE AND CRACKER SYSTEMS

This review of the glassy state phenomenon in applications for the food industry comprises two main parts. The first is a broad but brief overview of the so-called 'food polymer science' approach and its importance to food R&D studies of glassy solid and rubbery liquid states and glass transitions in food products and processes. The following elements of this approach are discussed: (i) the glass transition temperature (T(g)) and methods for its measurement in foods: (ii) plasticization by water and its effect on T(g); (iii) the concepts of 'water dynamics' and 'glass dynamics' in non-equilibrium food systems; (iv) Williams-Landel-Ferry kinetics in the rubbery state above T(g), (v) state diagrams; and (vi) the effect of molecular weight on T(g). A comprehensive and up-to-date listing of more than 400 literature references on the glassy state phenomenon and glass transitions in food materials and systems is featured in that part of the paper, and these references are also compiled and tabulated according to specific subject headings. The second part of this review highlights the application of the food polymer science approach in recently reported studies on the structure-function relationships of sucrose in cookie and cracker systems. This part describes (i) the sucrose water state diagram as a tool in understanding cookie and cracker baking; (ii) shortcomings of the traditional AACC sugar-snap cookie method as a test-baking system, in contrast to a new test system based on a model commercial-type wire-cut cookie formula; and (iii) a revealing illustration of sucrose functionality in cookie baking. The review concludes with a word about future prospects.