Effect of Enzymatic Treatments on Physico-chemical Properties and Quality of Juice and Syrup of Some Date Fruits

Abstract

This work aims to benefit from low quality fruits (of Saidy, Tamr and Manthor dates) by the production of enzymatically treated syrup with high quality value. From the chemical analysis, the total and reducing sugars were the predominate components in all studied date fruits varied from 50.5 to 81.8% and from 40.5 to 57.7% dry weight basis (dwb), respectively. The total acidity (as malic acid) of the studied date fruits ranged from 0.14 to 0.22%. The effect of different concentrations of pectinase enzyme, 0.5-2.0 % on the efficiency of date juice extraction process and physico-chemical proprieties of the obtained date syrup were studied. The enzyme treated date juices recorded the lowest values of viscosity, turbidity and color ( as absorbance at 520 nm), with the highest values of clarity compared with that of the untreated (control) samples. The results indicated that using 1% concentration of pectinase for 60 min at 50 °C gave a good result in terms of clarity, color and turbidity, but the recovery of total soluble solids was the highest after 90 min incubation time. The color values (as optical density at 420nm) of the enzyme-treated date syrups, Saidy, Tamr and Manthorranged from 0.499 to 0.574 compared with that of untreated date syrups which varied from 1.069 to 1.495. The treated Saidy date syrup had the highest clarity value followed by Tamr and Manthorsyrups. From the obtained results it can be concluded that the enzymatic treatments could be used to produce date syrup (Dibs) with good properties and high quality from second grade date fruits.