Uv 260 visible recording spectrophotometer

CPO (1 g) was dissolved in n-hexane (5 mL) and mixed with 10 mL methanol–water (80:20, v/v) in a glass tube for 2 min in a vortex (Ramadan et al. 2010 ). After centrifugation at 3000 rpm for 10 min, the hydroalcoholic extracts were separated from the lipid phase by using a Pasteur pipette then combined and concentrated in vacuo at 30 °C until a syrup consistency was reached. The lipidic residue was redissolved in 10 mL methanol:water (80:20, v/v) and the extraction was repeated twice. Hydroalcoholic extracts were redissolved in acetonitrile (15 mL) and the mixture was washed three times with n-hexane (15 mL each). Purified phenols in acetonitrile were concentrated in vacuo at 30 °C then dissolved in methanol for further analysis. Aliquots of phenolic extracts were evaporated to dryness under nitrogen. The residue was redissolved in 0.2 mL water and diluted (1:30) Folin–Ciocalteu’s phenol reagent (1 mL) was added. After 3 min, 7.5% sodium carbonate (0.8 mL) was added. After 30 min, the absorbance was measured at 765 nm using a UV-260 visible recording spectrophotometer (Shimadzu, Kyoto, Japan). Gallic acid was used for the calibration and the results of triplicate analyses are expressed as parts per million of gallic acid.