Modelling on Extractions and Micro Nano Encapsulation of Pistacia terebintus Cambium Layer Gum Essential Oil; Antioxidant Activity and Structural Approach Via XRD, SEM and TGA/DSC.

Abstract

This study explored the extraction and microencapsulation of essential oil from Pistacia terebinthus cambium layer gum (PTG-EO) using response surface methodology (RSM) to optimize extraction efficiency. Significant factors such as extraction method, time, and power were optimized for conventional extraction (CE) and microwave-assisted extraction (MAE), yielding 24.48 and 21.97% essential oil, respectively. Encapsulation efficiency was influenced by temperature, water activity, and oil/wall ratio. The chemical profile of PTG-EO revealed α-pinene as the main component (80.65%). Antioxidant activity, assessed using DPPH and ABTS, showed that freeze-dried nanoencapsulated powder (NcP-Fr) exhibited superior radical scavenging activity compared to spray-dried micro-encapsulated powders (McP-Sp). SEM analysis revealed microspherical encapsulation with sizes around 33.52 μm. Thermal degradation studies showed that the essential oil release from the wall material started at approximately 200 °C, with 10.06% of the oil being released by this temperature. X-ray diffraction analysis revealed the crystallinity/amorphous ratio (14.4/85.56%) and confirmed the stable, homogeneous encapsulation structure, supporting the strong antioxidant performance of NcP-Fr.