Abstract
This study systematically compared four extraction technologies – mechanical press, Soxhlet, supercritical fluid, and ultrasound – for recovering oil from apple seeds, a by-product of apple processing. Beyond yield and composition, we applied isothermal calorimetry to derive kinetic oxidation parameters, induction times (τ), and oxidizability indexes (O.I.), providing an engineering perspective on oil stability. Mechanical press oil exhibited significantly higher phenolic content (8.9 ± 0.42 mM GAE/L oil) and induction time (804 ± 9.2 h) compared to the oils obatined by supercritical fluid (706 ± 11 h), Soxhlet (641 ± 8.5 h), and ultrasound (480 ± 10 h). Shelf life at 25 °C was predicted as 278.7 ± 0.8 days for the oil obtained by mechanical extraction, 263.0 ± 4.0 days for the one from supercritical fluid, 208.1 ± 5.7 days for Soxhlet, and 170.1 ± 4.7 days for ultrasound-extracted oil. Importantly, amygdalin was detected in all oils (0.008 ± 0.001 μg/g oil) except that obtained by supercritical CO₂ extraction, highlighting a safety advantage of this method. These findings demonstrate that extraction technology not only affects oil composition but also critically influences oxidative stability, shelf life, and safety, offering practical guidelines for industrial valorization of apple seed by-products within a circular bioeconomy framework.