2.5. Preparation of aqueous sample extracts for determination of total phenolic content
Extracts were prepared according to the literature procedure, with a few modifications of Wojdylo, Oszmianski, and Czemerys (2007). Samples (1 g) were weighed and placed into a test tube. A total of 10 ml of 70% aqueous methanol was added, and homogenised with tissue tearor. Tubes were sonicated twice for 15 min at room temperature (20 °C). The extract was centrifuged for 10 min (1500g), and supernatants were used to determine the antioxidant activity of the total phenolic content