Abstract
Oils from apple seeds were extracted with the application of supercritical fluid (SFE) and Soxhlet techniques. The effect of SFE experimental variables such as pressure (10–30 MPa), temperature (40–60 °C) and carbon dioxide flow rate (1–8 L/h) on the yield, antioxidant activity and total phenolic content was investigated using a central composite design. The experimental data were fitted with a second-order polynomial equation using regression analysis. The maximum yield, obtained at the optimum processing conditions (24 MPa, 40 °C, 1 L/h of carbon dioxide flow rate, 140 min) was 20.5 ± 1.5% (w/w). For comparison, the yield from Soxhlet extraction was 22.5 ± 2.5% (w/w). Both techniques produced an oil with a fatty acids profile rich in linoleic acid. However, the extract from SFE was higher in linoleic acid (63.76 ± 4.96 g/100 goil) than that achieved by Soxhlet (49.03 ± 3.85 g/100 goil). Despite the higher unsaturated fatty acids content, SFE extracts reported a higher oxidative stability (21.4 ± 1.2 h) compared to that one extracted by Soxhlet (12.1 ± 1.1 h). This result was expport addressing the extraction of apple seed oil by supercritical fluid at pressures lower tha The most abundant phenolic compound found in the extract was phloridzin (2.96 ± 0.046 μg/gseed in SFE oil and 1.56 ± 0.026 μg/gseed in Soxhlet). Instead, amygdalin, one of the antinutrients present in seeds, was not detected in the SFE oil.