Co-crystallized sucrose with propolis extract as a food ingredient: Powder characterization and antioxidant stability

Propolis possesses health beneficial properties due to its antioxidant compounds; however, its solubility in alcohol and its strong and unpleasant taste limit the use of propolis extract in foods. This study explores the encapsulation of a propolis ethanolic extract by co-crystallization in a sucrose matrix to eliminate the alcohol and to obtain a propolis powder with suitable technological properties and high antioxidant activity to be used as a food ingredient. The effect of the propolis extract on colour, moisture content, solubility, particle size distribution, flow properties and spectroscopic characteristics (FTIR) of the co-crystallized powders was determined. Polyphenols and flavonoids content and antioxidant capacity (ABTS and DPPH) during storage of the powders were also analysed. The propolis co-crystallized powders showed moisture contents below 2% and good flow properties, except at the higher content of the extract. The FTIR results showed that the presence of propolis did not alter the crystalline sucrose structure. Entrapment yields higher than 84% (flavonoids) and 78% (poly-phenols) were obtained. During storage of the powders high stability of these compounds was observed at light, darkness and refrigeration conditions. Thus, co-crystallization technique constitutes a low cost alternative for the protection of bioactive compounds of propolis.