This study presented adsorption isotherms of texturized
soy protein at 10, 20, 30 and 40 C. Several models
were fitted to experimental data and the monolayer
moisture content, the total heat of sorption and the
water surface area of the product were calculated.
The adsorption isotherms obtained in this range of
temperature were very close, indicating week effect of
temperature. Isotherms at 20 and at 40 C crossed over
at a water activity value around 0.9. This fact is characteristic
of sugars-rich foods.
The GAB and Peleg models presented the best fit to
experimental data. As the GAB model predicted the
crossover, it was considered as the most suitable to predict
the adsorption isotherms of TSP in the temperature
range covered.
The total heat of sorption obtained for TSP decreased
as the moisture content increased.
The monolayer moisture content of TSP varied between
4.6% and 7.4% (db), within the studied range of
temperature, and decreased with increasing temperature.
The water surface area showed a similar behavior.