The composition of the extracting solvents significantly (P < 0.05) affected the
measured polyphenolic content. The acetone mixtures with the highest addition of acetic acid (solvent I: acetone/water/ acetic acid (70/28/2, v/v/v)) extracted most of the phenolic compounds when fresh and freeze-dried material had been used (Fig. 1A and C), whereas the acetone/water/acetic acid (70/29.5/0.5, v/v/v) mixtures appeared to be the best for extracting phenolics from frozen used matrices. It is well known that solvent polarity will play a key role in increasing phenolic solubility and acetone–water mixtures which were very effective solvents in our study are good solvent systems for the extraction of polar antioxidants