pps proceeding - Abstract Preview
pps proceeding
Symposium: S06 - Biopolymers and Polymer from Renewable Resources
Poster Presentation
 
 

MINIMIZING POLYMER DEGRADATION IN A SPRAY DRYING PROCESS OF ALOE VERA (barbadensis Miller) MUCILAGE (BIOPOLYMER)

CALDERAS FAUSTO (1)*, MEDINA-TORRES LUIS (2), NUÑEZ-RAMIREZ DIOLA MARINA (3), SANCHEZ-OLIVARES GUADALUPE (1), SANTIAGO-ADAME RUBEN (2), MANERO OCTAVIO (2)

(1) CIATEC, A.C. - LEON, GUANAJUATO - Mexico, (2) UNAM - MEXICO, D.F. - Mexico, (3) Universidad JuArez del Estado de Durango, UJED - DURANGO, DURANGO - Mexico

Rheological properties of Aloe vera mucilage reconstituted in aqueous solution by spray drying (SD) were evaluated on a shear rate range between 1 to 300 s-1, the rheological behavior was evaluated in function of mucilage concentration, temperature, pH and ionic strength. A decrease on shear viscosity was observed, showing non-newtonian behavior of the type thinning fluid (n<1) in all the imposed conditions. An increase in the pseudoplastic behavior was observed due to increased concentration of powder reconstituted in aqueous solution in the range of 3 to 6 g/100 mL. Viscosity values in the shear flows of the mucilage solution at 6 g/100 mL are higher than shown by a fresh solution mucilage, and 3 g/100mL xanthan gum at 25 °C. Cross model was properly adjusted to correlate viscosity data at shear-rate. The viscosity was found to be dependent on ionic strength, such as polyelectrolytic solutions, so, as the ionic strength increases, the viscosity decreases. This behavior was more remarkable when divalent cations are used. Aim, a marked dependence of viscosity on pH was observed, with increasing the pH of an acidic medium at an alkaline medium, viscosity increases. Aqueous solution of mucilage showed elastic flow similar at the Opuntia ficus indica mucilage. The linear viscoelastic spectrum in a frequency range of 0.1 to 200 rad/s tends to have weak gel behavior, with a crossing point between elastic module G’ and viscous modules G’’, (G’= G’’), which suggests a change in molecular conformation and a random coil arrangement in the molecule of reconstitute mucilage unlike fresh mucilage. Finally, fresh mucilage was let to spray drying at the best conditions of SD inlet: 1.5 L/ h flow, temperature of 150 °C and atomization rate of 27,500 rpm. The final powders were reconstituted in aqueous medium to compare the chemical composition and mechanical flow behavior with fresh mucilage, shown thickening and bioactive properties.