2.2.1. Drying

Fresh blossoms of *Sambucus nigra* L., intended for the study, were dried in a thin layer in the shade and turned periodically to a constant mass of the sample. The dried samples were homogenized, ground, packed in canvas bags, and stored at 18–20 ◦C, in the absence of light.

### 2.2.2. Determination of Antioxidant Activity (AOA)

The samples were extracted with water in a solid to solvent ratio (1:10 *w*/*v*) using an ultrasonic bath operating at 40 kHz at 40 ◦C for 20 min. The antioxidant activity of the extracts was evaluated by four methods based on different mechanisms.
