Assessment of the phenolic profile and biological activities of aqueous date seed extracts: A comparative analysis

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Date palm fruit (Phoenix dactylifera L.) is a well-known fruit that has become increasingly popular among consumers due to its pleasant flavor, nutrient-dense content, and nutraceutical characteristics. Date seeds are the main by-product of date fruit consumption and processing. Date seeds are usually incorporated in animal feed; however, their application in human contexts, such as food products, remains minimal. Nonetheless, they contain significant amounts of bioactive phenolic compounds, primarily flavonoids, which possess potential health benefits. The current study investigated and compared the phenolic profile, antioxidant, and antibacterial activities of aqueous extracts of nine different date seeds varieties. The phenolic profile, analyzed using high-performance liquid chromatography (HPLC-DAD-ESI-MS), showed that total phenolic compounds ranged from 1.05 to 1.24 mg/g in Reziz and Naghal varieties, respectively, with flavan-3-ols predominating in all varieties. Results of the ABTS and DPPH assays revealed that the antioxidant activities against free radicals were directly correlated with the overall phenolic content, particularly for caffeic acid. Indeed, all date seeds possessed antibacterial capabilities, with a stronger effect observed on Listeria monocytogenes than Escherichia coli. Additionally, date seeds demonstrated a promising source of oil rich in oleic and lauric acids, both of which are considered beneficial for health. According to our findings, date seeds are a significant source of bioactive compounds, which renders them ideal candidates for potential inclusion in human diets as food additives and nutraceuticals.