Yerba mate antioxidant powders obtained by co-crystallization: Stability during storage

• Yerba mate liquid extract was converted to free-flowing powder by co-crystallization.
• Powders with a high loading capacity of yerba mate polyphenols were obtained.
• Antioxidant activity of the yerba mate extract was not affected by the process.
• Co-crystallization is an alternative to protect the antioxidants during storage.
• Yerba mate powders could be used as an natural antioxidant in food formulations.

The interest on yerba mate has increased in the last years due to its high content of bioactive compounds related to health benefits. Antioxidant aqueous extracts of yerba mate were entrapped into a sucrose matrix by co-crystallization. The products were characterized in terms of their morphology, entrapment yield, loading capacity, water activity, moisture content, antioxidant activity, thermal behavior, solubility and hygroscopicity. It was found that the co-crystallization process led to high entrapment yield and maintained the antioxidant activity of the yerba mate extract towards DPPH radical. Also, the co-crystallized powders showed values of water activity, moisture content, hygroscopicity and flowability indicative of high stability and good handling properties. The total polyphenols content of the co-crystallized products remained almost constant along storage at 75% RH and 20 °C, however, fluctuations in their DPPH radical scavenging activity were observed.