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 foo d industry comprises two main parts. The first is a broad but brief ov erview of the so-called 'food polymer science' approach and its import ance to food R&D studies of glassy solid and rubbery liquid states and glass transitions in food products and processes. The following eleme nts of this approach are discussed: (i) the glass transition temperatu re (T(g)) and methods for its measurement in foods: (ii) plasticizatio n by water and its effect on T(g); (iii) the concepts of 'water dynami cs' and 'glass dynamics' in non-equilibrium food systems; (iv) William s-Landel-Ferry kinetics in the rubbery state above T(g), (v) state dia grams; and (vi) the effect of molecular weight on T(g). A comprehensiv e and up-to-date listing of more than 400 literature references on the glassy state phenomenon and glass transitions in food materials and s ystems is featured in that part of the paper, and these references are also compiled and tabulated according to specific subject headings. T he second part of this review highlights the application of the food p olymer 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 unders tanding cookie and cracker baking; (ii) shortcomings of the traditiona l AACC sugar-snap cookie method as a test-baking system, in contrast t o a new test system based on a model commercial-type wire-cut cookie f ormula; and (iii) a revealing illustration of sucrose functionality in cookie baking. The review concludes with a word about future prospect s.