Fixative diffusion in a frozen starch paste system

FERRERO C.; MARTINO M.N.; ZARITZKY NOEMI.

INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 1992 vol. 19 p. 595 - 605

0735-1933

Microscopic studies of frozen foods often involver indirect techniques in which the ice crystals are dissolved in a fixative solution and a porous matrix remained, where theholes represent the ice crystals. Isothermal freeze fixation was used to preserve the morphological structure of I0 % a corn starch paste. The selected fixative (commercialformaldehyde, absolute ethanol, water: I0, 45, 45 v/v), was characterized. Freezing curve of the fixative was determined; Fixative diffusion coefficient in the frozen system  was measured at different temperatures in conditions of unidirectional mass transfer in a semi-infinite medium. The activation energy for diffusion was also determined (Ea=95.11 ± 1.15 KJ/mol).Fixation times for the frozen starch paste at different temperatures were predicted from a mathematical model for unidirectional mass transfer with a discontinuous diffusioncoefficient. Predicted fixation times were verified experimentally.