Determinação da difusividade efetiva de raiz de chicória

Inulin is a fructooligosacharide found in diverse agricultural products, amongst them garlic, banana, Jerusalem artichoke and chicory root. Inulin generally is used in developed countries, as a substitute of sugar and/or fat due to its characteristics of fitting as functional and dietary food. Chicory root is usually used as source and raw material for commercial extration of inulin. The experiments consisted on drying sliced chicory roots based on a factorial experimental design in a convective dryer whose alows the air to pass perpendicularly through the tray. Effective diffusivity (dependent variable) has been determined for each experimental combination of independent variables (air temperature and velocity). The data curves have been fitted by the solution of the second Fick law and Page's model. Effective difusivity varied from 3.51 x 10-10 m² s-1 to 1.036 x 10-10 m² s-1. It is concluded that, for the range of studied values, air temperature is the only statistically significant variable. So, a first order mathematical model was obtained, representing effective diffusivity behavior as function of air temperature. The best drying condition was correspondent to the trial using the highest drying air temperature.

Formação das substâncias de reserva durante o desenvolvimento de sementes de urucum (Bixa orellana L. - Bixaceae)

Annatto seeds do not germinate during early stages of their development because of insufficient reserve substances. In situ analysis showed that the principal reserves are proteins and starch, deposited in endosperm cells. During the early stages of development, the starch grains were elliptic, because amylose was the minor component. During development, these grains became more spherical due to an increase in amylose relative to amylopectin. Endosperm cells do not contain protein bodies, but they accumulate proteins dispersed in the cytoplasm. At the final stage of development the proteins became compacted due to the dehydration of the seeds wich is part of the global process of orthodox seeds maturation. Natural fluorescence revealed aromatic amino acids, principally tryptophan and tyrosine in the proteins. The seeds reached their maximum dry weight after moisture contents had declined to around 60%. At this point the seeds presented maximum germination capacity.