Propolis is a complex resinous product gathered by honeybees whose chemical composition is highly variable, depending strongly on the plant sources available to the bees at the site of collection. Propolis from several locations in Portugal, including islands, was fully characterized in terms of physicochemical properties, phenolic composition and antioxidant activity, enabling the establishment of quality standards. Color, frequently used as a commercial parameter, was accessed by the first time in propolis with the CIELAB system, and proposed as a quick and reliable method for quality recognition. The results attested the existence of two different types of propolis within the six regions under study. One, the poplar propolis most common in temperate regions, revealed a high content in phenolics and show high bioactivity. The other, with darker green color is less rich in phenolics and generally less bioactive.
