Spray-drying of cactus pear juice (Opuntia streptacantha):: Effect on the physicochemical properties of powder and reconstituted product

A D-optimal experimental design with three center points was used to evaluate the influence of spray-drying conditions on the physicochemical properties of a powdered product obtained by drying cactus pear juice. Drying was performed in a laboratory spray-dryer (Pulvis GB 22 model) at two inlet air temperatures (205 and 225 degrees C), and two compressor air pressures (0.10 and 0.20 MPa). Commercial maltodextrins (10 and 20 DE) were used as carrier agents at two levels (18 and 23 %). Moisture content and hygroscopicity were evaluated in the powder, and vitamin C retention and total color change were measured in the reconstituted product. Analysis of variance (ANOVA) was performed with a confidence level of 95 % (p < 0.05). Moisture content of spray-dried powder and vitamin C retention of reconstituted product was mainly determined by the temperature-pressure, T*P, interaction. While for hygroscopicity, the pressure-concentration, P*C, interaction was the most important factor. The reconstituted product showed a slight change of total color (Delta E) with respect to natural juice and a significant effect of the maltodextrin concentration was found in this property.