Microencapsulation by spray-drying of bioactive compounds extracted from blackberry (rubus fruticosus)

Blackberry aqueous extract acidified with 2 % citric acid was spray-dried using gum Arabic (GA) and polydextrose (PD) as encapsulating agents at concentrations of 10 and 15 % and temperatures of 140 to 160 °C. All powders presented high solubility, ranging from 88.2 to 97.4 %, and the encapsulation conditions did not significantly affect the hygroscopicity. The powders produced with gum Arabic showed higher brightness than those with polydextrose. The anthocyanins retention in the microcapsules was 878.32 to 1300.83 mg/100 g, and the phenolics was 2106.56 to 2429.22 mg (GAE)/100 g. The antioxidant activity was quantified according to DDPH and ABTS methods, with values ​​ranging from 31.28 to 40.26 % and 27 to 45.15 %, respectively. The microscopy showed spherical particles for both encapsulating agents, and smooth surface with some concavities with the gum Arabic, and smooth or slightly rough surface when using polydextrose. The Pearson correlation coefficient showed a high correlation between the color parameters, L*, a*, b*, Hue, Chroma and browning index (BI), which were also strongly correlated with anthocyanins. Phenolic presented correlation with DPPH and ABTS values. The results showed that the best encapsulation condition was atomization at 140 °C and 15 % gum Arabic.