Extraction-dependent modulation of lipid structure, oxidative stability and bioactive composition of pomegranate seed oil: integrating process greenness with product quality

Abstract

Abstract Pomegranate seed oil (PSO) is a valuable source of punicic acid and lipophilic bioactive compounds; however, extraction conditions critically determine both oil quality and process sustainability. This study evaluated five extraction techniques—cold pressing (CP), Soxhlet extraction (SOX), ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and supercritical CO 2 extraction (SCO 2 ) – applied to two cultivars, with a focus on process–quality–sustainability relationships. The results demonstrate that extraction conditions govern both lipid recovery efficiency and the selective isolation of bioactive compounds. While SOX and SCO 2 provided the highest oil yields, their performance diverged in terms of oxidative quality and sustainability, reflecting differences in thermal exposure and solvent selectivity. SCO 2 extraction combined high recovery with favorable mass-based green metrics (low E-factor and PMI, high PME) and produced oils with the lowest oxidation level and highest oxidative stability. In contrast, CP yielded oils with high phenolic content but limited recovery, whereas SOX was associated with increased oxidation despite high yield. Although the overall fatty acid composition remained relatively stable, extraction significantly influenced the relative abundance of punicic acid and the positional distribution of fatty acids within triacylglycerols, indicating process-dependent selectivity. Similarly, the recovery of phenolics and carotenoids was strongly affected by extraction conditions, with compound-specific behavior highlighting limitations of total phenolic content as a sole indicator of bioactive quality. Overall, the results reveal clear trade-offs between extraction efficiency, product quality, and process greenness. From a technological perspective, SCO 2 offers the most balanced performance for applications requiring high stability and bioactive retention, whereas alternative methods may be selected when prioritizing extraction yield or minimal environmental impact. These findings provide a basis for the rational design and selection of PSO extraction strategies in industrial and sustainable processing.