Effect of spray drying on the microencapsulation of the blueberry natural antioxidants

Phenolic compounds obtained from blueberries have gained great attention due to their more effective bioactive roles in human health than whole berries. However, they are sensitive to environmental conditions and are therefore susceptible to degradation affecting their effectiveness. Microencapsulation of these compounds by spray drying provides a solution to these problems. This work aimed to study the effect of spray drying on the microencapsulation of the blueberry phenolic compounds to optimize the production of a powder rich in stable polyphenols. The phenolic compounds from blueberries were obtained using orbital agitation (220 rpm) during 5h at 25°C of blueberries, previously destemmed and washed, with acidified ethanol (52.6% v/v; pH 2.0 with citric acid) at a mass solvent to fruits ratio 4.2. This phenolic extract was spray dried under different conditions of inlet air temperatures (140 and 160°C) and encapsulating agent concentrations (20 and 30% w/v), using maltodextrin (14.7 dextrose equivalent). The drying yield, moisture content, water-solubility, total and surface phenolic content (by Folin-Ciocalteu), and encapsulation efficiency of total phenolic were investigated. The results obtained showed that the different conditions evaluated influenced on the drying yield, moisture content, surface phenolic content, and encapsulation efficiency of total phenolic. In this sense, the powders with the best characteristics were obtained with 30% w/v of maltodextrin at 160°C inlet temperature. These powders rich in blueberry polyphenols stabilized by microencapsulation, are easier to handle for application, so they could be used as functional food ingredients.