After blood samples were collected at baseline, the
volunteers consumed 500 mL orange juice and blood samples
were taken every 60 min up to 6 h. Blood samples were collected
in heparin-coated tubes and were centrifuged at 2000 g for
15 min at 4 C. After the plasma was collected, aliquots in triplicate
were immediately mixed with an equal volume of cold 6%
(wt:vol) metaphosphoric acid containing 1 mmol/L of the metalion chelator diethylenetriaminepentaacetic acid for vitamin C
and uric acid analysis. The remaining plasma was stored at
80 C for analysis of 8-epi-PGF2. For the multiple-doseresponse
study, the subjects were instructed to drink the juice at
home in 2 doses, 250 mL in the morning and 250 mL in the afternoon,
for 2 consecutive weeks. Blood samples were taken again
during the intervention on days 7 and 14 of the study.