Physical and functional properties of spray-dried powders from blackcurrant juice and extracts obtained from the waste of juice processing

Blackcurrants contain high levels of polyphenolics, particularly flavonols and anthocyanins, which contribute to their high antioxidant activity. The aims of this work were the recovery of bioactive compounds from the remaining solid (waste) after processing blackcurrant juice and to obtain spray-dried powders from the blackcurrant juice and extracts. The extraction of bioactive compounds from the fruit pulp was performed by ultrasound-assisted extraction. Experiments were conducted to select the more suitable solvent, and citric acid was chosen. Then, to optimize the extraction conditions (time, solvent concentration, and amplitude) an experimental design using a Box-Behnken Design was done. Comparing the optimized extract with the fruit, 31% total monomeric anthocyanins, 19% total phenolic compounds, and 10% antioxidant capacity were obtained. The optimized extract and the juice were mixed and spray dried, using maltodextrin as carrier matrix. A blackcurrant powder with low hygroscopicity 14.46 +/- 0.13 (g a.w./100g d.m) and high solubility 94.25 +/- 4% was obtained. High concentration of bioactive compounds and antioxidant capacity was recorded: Total monomeric anthocyanins 63.01 +/- 1 (mg cyn-3-glu/100g.d.m), total phenolic content 116.87 +/- 5 (mg gallic acid/100g d.m.), and antioxidant capacity 144.40 +/- 0.11 (mg eq Trolox/100g.d.m.).