Structure preservation of Aloe vera (barbadensis Miller) mucilage in a spray drying process

•Linear viscoelastic data for SD Aloe vera mucilage showed weak gel characteristics.•Aqueous solutions of Aloe vera showed similar elastic properties as fresh mucilage.•The best spray drying conditions minimized the degradation of fresh mucilage.•Structure preservation (random coil configuration) was achieved.•Antioxidant properties of fresh mucilage are preserved at the best drying conditions.

Aloe vera (barbadensis Miller) mucilage in powder form was obtained by spray-drying following by suspension in aqueous solution, to enable microstructure recovery. The rheological behavior of the reconstituted mucilage was evaluated as a function of mucilage concentration, temperature, pH and ionic-strength. Mucilage solutions exhibited shear-thinning non-Newtonian behavior. The viscosity was found dependent on ionic-strength. This dependence is more evident when divalent cations are used, although a strong rise in viscosity upon increasing pH is observed. Linear viscoelastic data show a predominant viscous behavior, but with a crossover point (storage module G′ = loss module G″) suggesting a change in molecular conformation to a random-coil arrangement of the mucilage microstructure. The spray-dried powders were compared with fresh mucilage, with regard to chemical composition and mechanical flow behavior. Results reveal a small structure modification during the spray-drying process, evidencing preservation of the mucilage microstructure when optimum spray-drying conditions are used, i.e., 1.5 L/h inlet flow, temperature of 150 °C and atomization rate of 27,500 rpm.