Foeniculum vulgare Miller bracts, revalorization of a local food waste

This research aims at the valorization of fennel by-products from the Campania region (Southern Italy). A phytochemical characterization of the hydroalcoholic extracts (HEs) and of the essential oils (EOs) from edible and non-edible parts (waste) of Foeniculum vulgare Mill. was carried out using HRESIMS and GC-MS. The analysis led to the identification in the extracts of flavonoids, phenolic acid derivatives, amino acids and fatty acids and essential amino acids and the presence of trans-anethole and limonene as main components of the EOs. Their antioxidant activity was investigated by DPPH e ABTS assays, showing moderate antioxidant activity for the HEs and no activity for the EOs. Antimicrobial activity was evaluated by disk diffusion method against some common bacterial food contaminants: Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, Salmonella sp., Shigella sp., Staphylococcus aureus. The EOs resulted active on almost all bacterial strains while HEs were found inactive. This study demonstrated that the waste obtained from fennel harvesting should t be considered as a valuable and reusable product.