Instant food from freeze-dried rice. Process parameters obtainment through data adjustment to mathematical model

Abstract

In order to design rice-based instant food, parboiled rice was freeze-dried. The experiment was performed using a lab-scale freeze-dryer, recording the freeze-dryer chamber temperature, as well as the moisture and temperature of the samples. The latter variable allowed us to establish a treatment time of 12 hours. Through Scanning Electron Microscopy, the porous diameter (17,6μm) and porosity (0,97) of the freeze-dried rice were estimated. These data, along with the registered moisture, were adjusted to a mathematical model, using data-analysis software, in order to obtain an effective diffusion coefficient of 2,58x10-10m2xs-1. Freeze-dried rice was employed to prepare dessert and soup of similar characteristics to those of local market products. Both aliments were analysed texturometricaly. Its sensory evaluation with a semi-trained panel allowed us to establish consumer preference profiles, which proved to favour instant food products over to the commercial ones.