Highly efficient method for synthesizing difructose anhydride iii

The present invention discloses a method for synthesizing a difructose anhydride III. The method comprises converting a sucrose to an inulin using an inulin invertase, and using an inulin fructotransferase to convert the inulin to synthesize the difructose anhydride III. The invention provides a conversion rate from the inulin to the difructose anhydride III of 40%-54%. To obtain a difructose anhydride III with higher purity, a yeast is used to remove a small monosaccharide from a reaction solution.