Ascorbic acid, phenolic content, and antioxidant capacity of red, cherry, yellow and white types of pitaya cactus fruit (Stenocereus stellatus Riccobono)

In order to sustain the growing interest in the consumption of pitaya cactus (Stenocereus stellatus Riccobono) fruit as potential neutraceutical food, the total phenolics and ascorbic acid contents were determined in four pitaya cactus fruit types (red, cherry, yellow and white). Total phenol and ascorbic acid concentrations were correlated to the antioxidant capacity (μmol Trolox eq g^-1 fresh sample). The results showed that the white and yellow types contained a higher amount of phenol compounds and ascorbic acid than the cherry and red types. A linear relationship was found between the fruit antioxidant capacity and the total phenol content (R²=0.97) and ascorbic acid content (R²=0.79), indicating that both of them contribute together to its antioxidant properties, but the contribution of ascorbic acid accounts only for 4-6 % of antioxidant capacity. The antioxidant capacity displayed by the four pitaya types are similar to those reported for some fruits of the Vaccinium genus, regarded as the fruits having the highest antioxidant capacity. The consumption of pitaya fruits could provide the same protecting effect against free radicals than berries of the Vaccinium genus, reducing risk of chronic diseases; thus pitaya fruits can be considered as potencial nutraceutical food.