Determination of pitaya seeds as a natural antioxidant and source of essential fatty acids

The antioxidant capacity and total phenolic content of seeds of three types of pitaya namely Hylocereus polyrhizus, Hylocereus undatus and Selenicereus megalanthus and the fatty acid content of pitaya seeds oil were examined in this study. The ethanolic extracts of H. polyrhizus seeds showed significantly high (p 0.05) total phenolic (43.9 mg GAE/100g dry weight) and flavonoid (50.8 mg CAE /100g dry weight) contents as compared to H. undatus and S. megalanthus and its aqueous extracts. DPPH assay showed similar trend showing that H. polyrhizus seeds had significantly higher (p 0.05) scavenging capacities (46.6%). FRAP test also indicated that the ethanolic extracts of H. polyrhizus seeds had significantly higher (p 0.05) reducing capacity (59.1mg Trolox/100g dry weight). The main fatty acids of pitaya seeds oil were C16:0, C18:0, C18:1, C18:2 with an exceptional high level of linoleic acid, up to 660 g/kg for S. megalanthus, 540 g/kg for H. undatus and 480 g/kg for H. polyrhizus.