Biofunctional profiling of date fruit extracts from enzyme inhibition to glycemic response in fortified muffins

Abstract

Date fruit extracts are rich in bioactive compounds with potential applications in functional foods and nutraceuticals. This study evaluated the polyphenol content and in vitro health-related properties (including antioxidant, antidiabetic, antilipidemic, and glycemic modulation) of five Saudi Arabian date varieties/products (Ajwa, Khalas, Sukkary, dried Sukkary, and dried Seffery). Flesh extracts were obtained through drying, grinding, solvent-based, and ultrasound-assisted extraction, followed by vacuum concentration. The extracts were characterized for total polyphenol content, antioxidant capacity, and inhibitory activity against key metabolic enzymes, including α-glucosidase, DPP4, pancreatic lipase, and cholesterol esterase. Ajwa exhibited the highest total phenolic content (8584 mg/kg DM) and strongest antioxidant capacity (29.0 mg DPPH, 95.7 mg ABTS, and 18.3 µmol Trolox per g DM), followed by dried Seffery. Khalas showed the highest lipase inhibition (29.83%), while Khalas and Sukkary had the strongest cholesterol esterase inhibition (35.60% and 34.46%, respectively), supporting lipid metabolism regulation. Dried Seffery, Khalas, and Sukkary demonstrated potent α-glucosidase inhibition (70.57%, 70.12%, and 69.79%, respectively), while Ajwa and dried Sukkary exhibited significant DPP4 inhibition (40.65 and 36.04%, respectively). To assess in situ glycemic modulation, date extracts were incorporated into muffins as 50% sugar replacers, resulting in an estimated GI reduction of up to 36%. This support using date fruit extracts as functional ingredients that offer antioxidant properties and promote metabolic health and glycemic control.