Abstract
Saudi Arabia is one of the major producers of date (Phoenix dactylifera) fruit. Date fruit flesh is considered a healthy food due to the presence of natural antioxidants. Green and innovative supercritical fluid (SFE, 52.5 °C temperature, 27.50 MPa pressure, 5 mL CO2/min flow rate) and subcritical (SubCO2, 250 extraction cycles, 29 °C temperature, 6.8 MPa, 12 h, ethanol solvent) extraction techniques were used to produce flesh extracts from four Saudi date fruits (Sukari (SKFE), Ambara (AMFE), Majdool (MJFE) and Sagai (SGFE)), and extracts prepared using 6 h Soxhlet extraction at 70 °C for 16 h using n-hexane as solvent, were taken as control. SFE produced the highest (p < 0.05) extract yields, whereas the SubCO2 method recovered significantly higher (p < 0.05) amounts of phytochemicals. Total phenolics (186.37−447.31 mg GAE/100 g), total flavonoids (82.12−215.28 mg QE/100 g), total anthocyanins (0.41−1.34 mg/100 g), and total carotenoid (1.24−2.85 mg BCE/100 g) were quantified in all the flesh extracts. The biological properties evaluation showed that flesh extracts had high antioxidant (17.79−45.08 µg AAE/mL), antiradical (191.36−34.66 µg/mL DPPH IC50), ferric-reducing (2.18−5.01 mmol TE/100 g) and ABTS-scavenging (444.75−883.96 µmol TE/100 g) activities. SubCO2 was the best technique and Majdool the best date variety, in terms of both phytochemicals and biological properties.