PRODUCTION OF FRUCTOSE RICH SYRUPS USING INVERTASE FROM DATE PALM FRUITS

The invertase activity of eight varieties of date palm from the Tunisian oasis of Gabes and Jerid was extracted with distilled water and concentrated by ammonium sulfate precipitation at 80% saturation. The determination of invertase specific activity in these extracts showed that it was variable and higher in fruit from Gabes varieties (from 0.23 to 1.38 U/mg). Additionally, zymogram analysis showed the presence of at least two isoforms for tested extracts. The invertase extracted from Korkobbi variety has been more characterized. It presented an optimal temperature, optimum pH, apparent Km, apparent Vmax and catalytic efficiency of 45C, 3.54, 8.4 mM, 17.3 mu mol/min/mL and 2.05 mM/mu mol/min/mL, respectively. This invertase was mixed with an aqueous extract rich in sucrose prepared from the Deglet Nour variety. A high-fructose syrup was obtained after only 30 min of incubation. This syrup produced with a very low cost could be used as food additive in the food industry.