Author/Authors :
-، - نويسنده Department of Food Science, Engineering and Technology, University of Tehran, Karaj, Islamic Republic of Iran. Fathi, G. , -، - نويسنده Department of Food Science, Engineering and Technology, University of Tehran, Karaj, Islamic Republic of Iran. Labbafi, M. , -، - نويسنده Department of Food Science, Engineering and Technology, University of Tehran, Karaj, Islamic Republic of Iran. Rezaei, K. , -، - نويسنده Department of Food Science, Engineering and Technology, University of Tehran, Karaj, Islamic Republic of Iran. Emamjomeh, Z. , -، - نويسنده Department of Food Science, Engineering and Technology, University of Tehran, Karaj, Islamic Republic of Iran. Hamedi, M.
Abstract :
Ultrafiltration (UF) was used for decolorization of an industrial Iranian date syrup. Experimental results were obtained by using two different concentrations of the date syrup (40 and 50 °Brix) and two different membrane pore sizes (15-20 and 30-50 kDa molecular weight cut-off values) under different trans-membrane pressures (TMP: 40, 70, 110 and 150 psi). The membrane with a pore size of 15-20 kDa resulted in average decolorization of 56% and turbidity reduction of 90%. Increasing TMP from 40 to 150 psi led to the decolorization and turbidity reduction of 48 and 82%, respectively. When the concentration of date syrup was increased from 40 to 50 °Brix, the levels of decolorization and turbidity reductions reached 47 and 78%, respectively. Reduction in the turbidity of date syrup was correlated with increases in the lightness (L*) and yellowness (b*), while the redness (a*) was decreased. Changes in the fructose and glucose levels due to the UF operation were much less than those of color and turbidity.
