Effect of spray drying on the physicochemical properties and color stability of the powdered pigment obtained from vinification byproducts of the Bordo grape (Vitis labrusca)

The aim of this work was to produce and evaluate powdered pigments obtained from vinification byproducts of Bordo red grapes (Vitis labrusca). The concentrated extract obtained from the byproducts was spray dried under different conditions of inlet air temperatures (130-170 degrees C) and carrier concentration (10-30%) in a total of 9 treatments. Besides, one sample of freeze-dried extract was obtained to comparison. The samples were analyzed by: moisture content, anthocyanin retention, hygroscopicity, water solubility, moisture sorption isotherms, infrared spectroscopy (FTIR), and changes in color during storage. Moisture content and anthocyanin retention were influenced by the drying temperature and carrier agent concentration, whereas hygroscopicity was more influenced by the carrier concentration. The moisture sorption isotherms were also influenced by the maltodextrin concentration. Infrared spectroscopy indicated that the extract was covered or encapsulated by the carrier agent. During storage, samples containing maltodextrin preserved the color more intensely than the freeze-dried sample and the liquid extract. Results suggested that spray drying of Bordo grape extracts using maltodextrin produces powders with low moisture content, low hygroscopicity, high solubility, and stable color. These results evidence that this byproduct of wine production may be used as a natural source of pigments. (C) 2013 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.