After incubation at room temperature for 2 h, the absorbance of the solution was measured at 750 nm using a UV/VIS spectropho- tometer (Beckman Coulter DU1800).
The total phenol content was calculated based on a standard curve of Gal- lic acid, which was linear within a range of 50 - 400 mg∙l−1 (R2 = 0.9954).
The results were presented as the mean of the nine analyses and expressed as milligrams of Gallic acid equivalents (GAE) per gram dry weight (mg GAE∙g−1 DW) [17].