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°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 (ΔE) with respect to natural juice and a significant effect of the maltodextrin concentration was found in this property.

The objective of this study was to assess the effectiveness of the blends with different levels of lactose-maltodextrin (8:5, 10:5, and 12:5 % w/v) during the spray-drying of the passion fruit juice. The drying was carried out in a laboratory spray dryer (Pulvis GB 22 model) at two inlet air temperatures (180 and 190 ºC), and two air pressures (0.10 and 0.20 MPa). The moisture content, hygroscopicity and vitamin C retention were evaluated in the powder obtained. Response surface plots (p<0.05) showed that the lowest values of the moisture content and hygroscopicity were reached in the temperature range of 188-190 ºC and at 12:5 % (w/v) concentration of lactose-maltodextrin; the best vitamin C retention level occurred at 180 ºC and 0.2 MPa.