Structural properties evaluation of extracted date fruit (Phoenix dactylifera L.) juice at different extraction temperatures

• Physicochemical properties of date juice are affected by extraction temperatures. • Extraction temperature of 25 °C yields a light colour and the most thermally stable juice. • Juice extracted at 90 °C produces juice with the highest total phenolic content amount. • Juice extracted at 75 °C exhibits the highest a solid-like property and viscosity. Date juice, a nutritious product derived from date fruits, is gaining popularity in the food industry for its health benefits and versatility. This study aims to evaluate the impact of extraction temperatures (25 °C, 50 °C, 75 °C, 90 °C) on the structural and physicochemical properties of date juice, where rheological profiles and other parameters (total soluble solid and fibre, reducing sugar, colour, browning index, hydroxymethylfurfural (HMF), total phenolic content (TPC), functional groups, thermal stability) were examined. The juice TPC content increased significantly ( p < 0.05) with extraction temperatures, from 6.45 µg GAE/mL (25 °C) to 34.93 µg GAE/mL (90 °C). DPPH antioxidant activity showed a slight improvement, as indicated by reduced IC₅₀ values. The juice colour darkened with higher extraction temperatures, while no HMF was detected, suggesting the processing method is safe and preserves juice quality. All juices exhibited non-Newtonian flow behaviours, with juice extracted at 75 °C exhibited the highest viscosity (0.323 Pa·s) and juice extracted at 90 °C the lowest (0.030 Pa·s). Rheological results confirmed gel-like behaviour which weakened at 90 °C, presumably due to degradation of soluble polymers, consistent with reduced thermal stability. These findings highlight the importance of extraction temperature in enhancing date juice properties, offering novel insights for optimizing production in the date processing industry.