Abstract
Dates contain over 75 % reduced sugars in form of glucose and fructose. Saccharomyces cerevisiae strain ATCC 36858 has been used to selectively ferment the glucose component in the date syrup into ethanol. Separation of ethanol from the fermentation resulted in higher fructose concentrations. The selective fermentation was performed at three temperatures, i.e., 27, 30 and 33 degrees C at agitation speed of 120 rpm and initial syrup concentration of 15 % (150 g/L). The fructose fractions in the remaining sugar solution were 97.5, 99.2 and 97.8 % for fermentation temperatures of 27, 30 and 33 degrees C respectively. The corresponding fructose yields were 82.1, 95.1 and 85.7 %. However, for the wild non-selective strain all fructose was fermented simultaneously with the glucose component. The fructose fractions obtained here are much higher than those obtained with the classical isomerization processes that yield 55 % fructose syrups.