Carotenoids identification and quantification were performed by HPLC analysis according to a modified method of Mendes et al. [26]. A Supelcosil™ LC-18 column, 15 cm × 4.6 cm, 5 μm (Supelco Inc., Bellefonte, PA) was used to separate individual carotenoids at ambient temperature. Samples (50 μL) were dissolved in methanol/dichloromethane (1:1, v/v) and the mobile phase, methanol with 10% (v/v) acetonitrile, was delivered at a flow rate of 1 mL/min under isocratic conditions. The separated lutein, α-carotene and β-carotene peaks were monitored at 450 nm wavelength. β-Carotene and lutein standards were used for identification and quantification based on a calibration curve. Since it was not possible to obtain α-carotene standard, it was assumed that α-carotene has a similar response factor to that of β-carotene [27] and the concentration of α-carotene in various samples were calculated based on the calibration curve of β-carotene.