The total phenolics content were performed using the method
described by Spanos and Wrolstad (1990). For this purpose, 100 mL
of the sample extract, 900 mL of nanopure water, and 5 mL of 0.2 N
Folin–Ciocalteu reagents were added in a 15 mL volumetric flask.
The contents were mixed and allowed to stand for 5 min at room
temperature. Next, 4 mL of saturated sodium carbonate (75 g L1
)
was added. Solutions were mixed and allowed to stand at room
temperature for 2 h. The absorbance of the final solution was
recorded with a spectrophotometer (Analytic Jena UV–vis L 40,
Germany) at 765 nm with respect to the blank solution (80%
aqueous acetone). The results were expressed as mg of gallic acid
equivalent per 100 g of fresh weight (mg GAE 100 g1 fw).