Abstract:
Ultrafiltration (UF) was used for decolorization of
an industrial Iranian date syrup.
Experimental results were obtained by using two dif
ferent 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 tr
ans-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 o
f 48 and 82%, respectively. When the
concentration of date syrup was increased from 40 t
o 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 lig
htness (L*) and yellowness (b*), while
the redness (
a
*) was decreased. Changes in the fructose and gluco
se levels due to the UF
operation were much less than those of color and tu
rbidity.
