Unveiling multifunctional bioactive phytochemicals and antioxidants in tangerine pomace for value-added applications

Tangerine pomace (TGP), a byproduct of juice processing, holds great potential as a source of health-promoting phytochemicals. Its chemical complexity, however, requires high-resolution analytical techniques and tailored solvent strategies for effective extraction. This study utilized comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC-TOF-MS) and other advanced instrumentations to thoroughly profile solvent-specific phytochemicals extracted with ethanol and n-hexane. The ethanol extract contained 258 volatile and semi-volatile compounds, including high levels of flavonoids (85.1 mg/g), particularly hesperidin and narirutin, along with organic acids and sugars. In contrast, the hexane extract primarily comprised lipophilic compounds like fatty acid esters, phytosterols, terpenoids, and tocopherols. The ethanol extract also showed 1.7-2.2 times higher antioxidant activity, driven by its enriched phenolic and flavonoid contents. These findings demonstrate the solvent-dependent extraction efficiency and the diverse phytochemical profile of TGP, supporting its potential as a sustainable source of functional ingredients for food, cosmetics, and pharmaceuticals.