Comparative study of rheological and textural behavior of date syrup, date concentrate, Date liquid sugar and sugar solutions

Rheological study of date syrup, date concentrate and date liquid sugar can improve their industrial applications specially for sugar (sucrose) substitution. In this research the rheological behavor of date syrup, date concentrate, date liquid sugar and sucrose solutions was investigated using a Brookfield Viscometer at 50, 55, 60 and 65 °Brix, 25 °C and shear rate of 80-480 s-1. The variables were product type and concentration. Moreover, for textural evaluation a texture analyser was used to examine date syrup, date concentrate and date liquid sugar at 50, 60 and 70 °Brix. The results showed that the Power law model was suitable to the rheological behavior of all samples and all concentrations. In date syrup by increasing concentration from 50 to 65 °Brix, consistency coefficient (K) increased, flow behavior index (n) decreased and the sample became more shear thinning. However, all other samples were Newtonian. Therefore a similar flow type behavior for these three samples is expected in food processings. Among all tested concentrations, the date syrup sample with a Brix of 65 had the highest consistency coefficients. This indcates using date syroup in food formulations, usage level of hydrocolloids can be reduced. These findings were confirmed by texture data.