2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

Heat-moisture treatments of starches have been explored with respect to glass and melting transitions of amorphous and crystalline regions of the native structure, but responses to high hydrostatic pressure (HHP) treatments have been interpreted previously only on the basis of crystalline aspects of starch. In order to explore the effects of heat and HHP on glass and crystalline transitions of starches, and the distinctive contributions of amylopectin and amylose, with respect to: annealing, gelatinization, pasting, and retrogradation, an experimental design with dent and waxy corn starches was conducted, using pressure (atmospheric to 600 MPa), temperature (room to 90°C), and time (5 to 60 min). The type and level of plasticizer were included as design factors to study the modulation of responses by: water (lowest Tg = most efficient), salt-water (non-glass-forming), and sucrose (glass-forming). As an example of the results, when 50% (w/w) starch slurries were HHP-treated for 15min at 25°C, treatment at 300 MPa showed no effects on glass or crystalline transitions, but treatment at 600 MPa showed significant extents of gelatinization, annealing, and subsequent retrogradation, for both starches. The designed use of thermal plus HHP processing could enable enhanced food quality (novel textures, retained flavors and nutrients), conformance (reduction in process variation), and safety (preservation).