Samples were processed in duplicate according to the procedure described by Iha and Sabino (2008), that was used as reference method. Briefly, 5 mL aliquots of homogenized juice samples were pipetted into 15 mL centrifuge tubes containing 0.5 g sodium bicarbonate and 5 mL ethyl acetate:hexane (96:4). The centrifuge tubes were closed and vigorously shaken for 5 min and, after centrifugation for 1 min at 580 g, 3 mL of the organic phase were transferred to tubes containing 30 ml acetic acid. The mixture was evaporated to dryness in a nitrogen stream and the residue immediately dissolved in 1 ml of 0.1% acetic acid (pH 3.2) in a Vortex mixer (Fanem) for 1 min.