Rheological properties of a newly nutritious dairy drink from milk and date extract concentrate (DIBBS)

Abstract

Rheological properties of date extract concentrate (dibbs), milk, and milk-dibbs drink of different dibbs concentration were experimentally determined. The dibbs was extracted from three date cultivars (Khlass, Sukkari, and Nubot Seif), and then added to milk in a specified amounts ranging from (2.5 to 15 mL dibbs/100 mL milk) to form the sweetened and nutritious milk-dibbs drinks. It was found that milk, dibbs, and milk-dibbs drinks exhibited pseudoplastic behavior following a power law model at the temperature range 5 to 65°C. The flow behavior indices ranged between 0.705 to 0.888 for dibbs and milk-dibbs drinks based on date cultivar, temperature, and concentration. For the dibbs and milkdibbs drinks, the consistency index was found to decrease with the increase of temperature, and increase with the amount of dibbs added. Results showed a significant influence of date cultivars on the rheological properties of dibbs and milk-dibbs drink. Utilizing the Arrhenius model, the activation energies ranged from 5 × 103 kJ kg-1 mol-1 to 21 × 103 kJ kg-1 mol-1 at shear rate 100 s-1.