Impact of Roasting Temperature on Antioxidant Activities and Characterization of Polyphenols in Date Seed Beverages From Different Cultivars

This experiment aimed to analyze the antioxidant capacity and composition of polyphenolic compounds from date seed beverage produced from eight date palm cultivars subjected to three roasting temperatures (180°C, 200°C, and 220°C) from light roasting to dark roasting. Total phenolic content in date seed beverages at light roasting ranged from 4.98 to 14.09 mg GAE/g, higher than that of the medium roasting (3.66-8.65 mg GAE/g) and dark roasting intensity (1.66-6.33 mg GAE/g). Date seed beverages produced from lightly roasted seeds had higher antioxidant capacity than those roasted at medium and dark levels. Using LC-ESI-QTOF-MS/MS, a total of 69 polyphenolic compounds were detected, classified into three groups: 17 phenolic acids, 40 flavonoids, and 12 other phenolic compounds. Our findings demonstrated a decrease in phenolic content as date seed roasting intensity increased from light to dark roasting, accompanied by variations in both phenolic composition and antioxidant capacity across cultivars.