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Date palm (Phoenix dactylifera L.), a strategic oasian species in most Mediterranean regions, is often known by the commercialized Deglet Nour variety. However, many other common varieties that might have high importance are neglected. The current study aims to evaluate the nutraceutical and functional properties of six common date palm cultivars, collected from three Tunisian oasian regions. The biochemical composition and antioxidant potential of these date cultivars were investigated. Total polyphenols (TPP), total flavonoids (TF), and condensed tannins (CT) contents varied significantly between varieties. In particular, the Ftimi cultivar had the highest amounts of TPP, TF, and CT (204.04 ± 12.85 mg·GAE/100 g·FW, 117.35 ± 7.49 mg·RE/100 g·FW, and 147.93 ± 7.65 mg·CTE/100 g·FW, respectively). Similarly, this cultivar exhibited the highest antioxidant activity with 131.59 ± 11.54 mg·TE/100 g·FW and 106.57 ± 2.33 mg·TE/100 g·FW, respectively, for DPPH and ABTS+ assays. Contrary to the Deglet Nour variety, the six common dates contain a high amount of fructose and glucose (reducing sugars) and a low content of sucrose. LC-ESI-MS analysis showed that “Kenta” had the highest number of polyphenolic compounds (19 compounds) followed by “Ftimi” with 18 compounds, whereas “Deglet Nour” has only 15. Six major compounds (quinic acid, epicatechin, rutin, hyperoside, luteolin 7-O-glucoside, and kaempferol) were omnipresent. These findings highlight the high potential of neglected date palm varieties and confirm their richness with nutraceuticals and natural antioxidants.

In this study, the antioxidant activities and detailed phenolic profiling of extracts from seven cultivars of date seeds were investigated. Significant differences were detected among cultivars. Total phenolic content (TP) ranged between 135.9±12.1 and 284.86±21.9 mg GAE/g DM. The total flavonoid value varied between 34.20±0.34 and 94.46±1.04 mg RE/g DM. The condensed tannin ranged from 24.17±1.13 to 201.60±9.95 mg CTE/g DM. Phloroglucinolysis was used to depolymerize the bound polyphenols. Results show the presence of phenolic acids: Hydroxybenzoic acid, hydroxycinnamic acid, and a high amount of flavan‐3ols (monomers, dimers, and trimers). Before depolymerization, the highest amount of total polyphenols was identified in Kenta (8.48 g/kg) and the lowest was detected in Hessa (4.74 g/kg). After depolymerization, the flavan‐3‐ols increased significantly, ranging between 46.91g/kg in Hessa and 72.38 g/kg in Deglet Nour, with a high degree of polymerization (DP) in all cultivars. It can be concluded that date seeds represent a good source of bioactive compounds.

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