Sustained release and antioxidant efficiency of encapsulated Pistacia lentiscus essential oil in sodium alginate/gelatine systems

This study aimed to enhance the stability and achieve controlled release of Pistacia lentiscus essential oil (PLEOs) via microencapsulation using a sodium alginate–gelatine complex coacervation system. Chemical composition of PLEOs was analysed by gas chromatography-mass spectrometry. Microcapsules were characterised using Fourier-transform infra-red spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy. Optimised PLEOs microcapsules exhibited a zeta potential of −28.33 ± 0.90 mV, encapsulation efficiency (93.28 ± 0.31% w/w), retention efficiency (95.30 ± 0.11% w/w), and particle diameters from 10 to 40 µm. Thermal stability was significantly improved, with the degradation stage shifting from 110–340 ± 5 °C for PLEOs to 200–370 ± 5 °C after encapsulation. Antioxidant activity of PLEOs microcapsules increased to 56.0 ± 3.1%. In vitro digestion showed pH-dependent sustained release (15–60% w/w over 200 min; R2 ≥ 0.95). These findings demonstrate that complex coacervation effectively protects PLEOs and ensures controlled release.