The total phenolic contents of flesh and peel samples of red pitaya were determined using a modified Folin-Ciocalteu method (Wolfe et al., 2003). A 125 ll aliquot of a known dilution of the extract was added to the test tube and combined with 0.5 ml of Folin– Ciocalteus reagent. The tubes were vortexed for 15 s and then allowed to stand for 6 min at 20 C. About 1.25 ml of 7% sodium carbonate solution was then added to the test tubes, and the mixture was diluted to 3 ml with distilled, de-ionized water. Colour developed for 90 min, and absorbance was measured at 760 nm using the Hewlett Packard UV–Vis spectrophotometer (Palo Alto, CA).