Blackberry (Rubus fruticosus) juice possesses compounds with antioxidant activity, which can be protected by different biopolymers used in the microencapsulation. Therefore, the effects of cell wall material including maltodextrin (MD), Arabic gum (GA) and whey protein concentrate (WPC) were evaluated on the physicochemical and antioxidant properties of encapsulated blackberries using a spray-drying technique. Anthocyanin concentration, polymeric colour, total polyphenols, radical scavenging activity of the 1,1-diphenyl-2-picrilhydrazil radical, reducing power and the stability at different storage conditions were evaluated. GA and MD conferred a similar protection to the antioxidant compounds when the microcapsules were stored at low water activities (aw < 0.515) in contrast to at a high moisture content (aw > 0.902), whereas WPC presented a high protection. Therefore, the selection of the best wall material for blackberry juice encapsulation depends of the conditions of storage of the powder.

The aim of this work was to optimize the drying process of vegetal pear and minimize energy resources (cost) under prefixed limits involving vegetal pear moisture, color, and productivity. The optimization of vegetal pear drying was made by using response surface methodology (RSM) for minimum process cost and color difference between fresh and dried samples (moisture ≤0.10 g water g d.m.⁻¹). A pilot-plant dryer was used for dehydrating vegetal pear slices (0.5 cm thickness). The tests were carried out at different air temperature (60 to 70°C), samples diameter (4 to 7 cm), and pretreatment with ascorbic acid solutions (0–0.1% w/w). The optimum drying conditions were found at air temperature of 63°C with 5-cm sample diameter and 0.075% of ascorbic acid concentration. On the optimized drying conditions, dried vegetal pear presented values with moisture content of 0.052 g water g d.m.⁻¹, color difference of 11.65, production rate of 0.0073 kg h⁻¹, and total cost of $30.58/kg dried product⁻¹