Effects of microwave drying on physicochemical characteristics, microstructure and antioxidant activities of date fruit powders

This study compared the Degla-Beida (DB) and Mech-Degla (MD) date varieties in terms of morphological attributes, biochemical composition, microwave drying kinetics and functional characteristics. DB dates were larger and heavier than MD dates, with higher sugar (72.41%) and ash content (2.04%). Both varieties reached 5–7% moisture content, with DB being slightly higher. DB powder contained more sugars (76.10%) and lipids (0.49%) and showed higher polyphenols (1046.01 mg GAE/100g), flavonoids (298.67 mg QE/100g), and antioxidant activity (IC₅₀ DPPH: 0.40 mg/ml, IC₅₀ ABTS: 0.73 mg/ml) compared to MD. MD powder demonstrated superior water retention (98.33%) and flow properties (Carr’s index: 5.78, Hausner ratio: 1.07). FTIR analysis showed that microwave drying preserved essential bonds in both powders, while SEM revealed crystalline morphology in MD and densely packed fibers in DB. This study highlights the nutritional, functional, and industrial importance of these date varieties after MW processing.