OPTIMIZATION OF SUPERCRITICAL CO2 EXTRACTION, ANALYSIS OF PHYSICOCHEMICAL PROPERTIES AND ANTIOXIDANT ABILITY OF DRAGON FRUIT SEED OIL (Hylocereus polyrhizus)

Abstract

Red-fleshed dragon fruit (Hylocereus polyrhizus) seeds, an abundant agro-industrial
byproduct, contain valuable oil rich in unsaturated fatty acids with potential antioxidant
properties. This study aimed to optimize the oil’s supercritical carbon dioxide (SC-CO₂)
extraction and evaluate its physicochemical characteristics and antioxidant activity. Using a
Central Composite Design based on Response Surface Methodology (RSM), optimal
extraction conditions were identified as 49.58 °C, 6526 psi, and a 6.46 L/min CO₂ flow rate,
achieving an oil yield of 13.41 ± 0.42% (w/w), corresponding to 52.89 ± 1.67% recovery. The
extracted oil exhibited a high iodine value (129.15 ± 0.746 g I₂/100 g), indicating significant
unsaturation, an acid value of 17.29 ± 0.137 mg KOH/g, volatile content of 6.19 ± 0.0021%,
and a total polyphenol content of 0.384 mg GAE/g. Vigorous free-radical scavenging activity
was confirmed via DPPH and ABTS●+ assays, with IC₅₀ values of 0.52 and 0.195 mg/mL,
respectively. These findings demonstrate that dragon fruit seed oil obtained via optimized SCCO₂ extraction is a rich source of unsaturated lipids and natural antioxidants, highlighting its
significant potential as a natural ingredient in functional foods, nutraceuticals, and cosmetic
products. In contrast, this green extraction method adds value to agricultural by-products.