The chemical composition, carotenoids, anthocyanins, total phenolic content, total flavonoid content, and antioxidant activity of three date seed cultivars, mainly Barhi, Ruthana, and Qatarah, were investigated. Date seed bioactive compounds were extracted by using different extraction solvents. The chemical analysis revealed that the Barhi cultivar has the highest moisture and fat content, while Ruthana has the highest carbohydrate content. There were no significant differences in protein and ash contents among the three date seeds. Ethanol (100%) showed the highest bioactive compound contents and antioxidant activity, whereas water showed the lowest content among the six solvents. Generally, all the date seed cultivars contain high amounts of phenolic, flavonoid, and antioxidant activity. The carotenoid content was highest in the Barhi (1.98 mg/g DW) followed by Qatarah (1.25 mg/g DW) and Ruthana (0.89 mg/g DW) seed, while the anthocyanin content was highest in the Ruthana cultivar (5.51 ± 0.71 cyanidin 3-glucoside/g DM.) and lowest in Barhi date seed (3.335 ± 0.23 cyanidin 3-glucoside/g DM.). Among the three date seeds, the Ruthana seed showed the highest phenolic (93.36 ± 0.30 mg GAE/g) and flavonoid compounds (59.9 ± 0.44 mg CE/g), DPPH activity (78.6 ± 0.92%), and total reducing power (60.3 ± 0.09%). The optimum solvent for the extraction of the antioxidants and their activity in each date seed was validated by using partial least squares regression (PLS). The results revealed a variation in the valid and optimum extracts for each seed; 100% ethanol extract for Barhi seed and mixture of methanol:ethanol:water (M 40:E40:W20) extract for Ruthana and Qatarah cultivars were the best solvent systems. The high natural antioxidant content of date seeds indicates that they can be considered functional ingredients for food and medicinal uses.

This study investigated the chemical composition, and total phenolic content(TPC), total flavonoid content (TFC), and antioxidant activity Reziz date pomace extracted using different solvent system. The recovery, bioaccessibility, and stability of bioactive compounds were evaluated using In vitro gastrointestinal digestion. The results showed that pomace rich source of fiber but low in fat, and protein. Extraction data revealed that methanol, and ethanol were the most effective solvent for TPC and TFC extraction with higher antioxidant activity. In vitro gastrointestinal digestibility significantly affected recovery, bio-accessibility and stability of bioactive compounds. The TPC, TFC, and antioxidant activities were significantly increased after the mouth digestion but decreased during the gastric and intestinal digestion. The bioaccessibility of polyphenol and flavonoid were 35.22% and 23.57% respectively after the intestinal digestion. The chyme insoluble fraction (pellet) showed higher bioactive compounds and antioxidant activity compared to the chyme soluble fraction. The high fiber content of the date pomace seemed to affect the bioaccessibility of the bioactive compounds. TPC or TFC and the antioxidant activity determined by DPPH and ABTS were found to have a positive correlation with the oral, gastric, and intestinal digestion. The GC-MS analysis of digested date pomace in mouth, gastric, or intestinal digestion revealed an increase in the number of peaks (compounds) compared to the undigested sample. According to these findings, Ruzeiz date pomace could be utilized as a bioactive ingredient source in formulation of functional foods to promote healthy life.