Method for increasing yield of sucrose

In a method for producing sucrose from beets wherein raw beet juice extracted from beets is purified into beet juice, and the obtained beet juice is concentrated and thereafter converted in sugar-boiling treatments of a sugar-boiling and centrifugal separation process into massecuite which is separated by centrifugal treatments of said sugar-boiling and centrifugal separation process into molasses and sucrose crystals, the improvement which consists essentially of:

• adding alpha-galactosidase to act upon beet juice having a concentration of 10.degree. to 60.degree. Brix and withdrawn before said sugar-boiling and centrifugal separation process thereby hydrolyzing raffinose contained in said beet juice into sucrose and galactose, and wherein said beet juice to which the alphagalactosidase is added is the beet juice before a deionization treatment included in the purification process, and the hydrolysate hydrolyzed by the addition of alpha-galactosidase is subjected to said deionization treatment after removing the alpha-galactosidase therefrom;
• separating alpha-galactosidase from the hydrolysate thus obtained, subjecting said resultant hydrolysate to the process following the process from which the beet juice has been withdrawn, and recovering sucrose contained in said hydrolysate in said sugar-boiling and centrifugal separation process, wherein by the hydrolysis of raffinose the amount of the raffinose contained in the beet juice is decreased and the amount of sucrose is increased with the result that the sucrose purity in the beet juice is increased, and both the increase of sucrose purity and the decrease of the raffinose cause the growth of sucrose crystals to be accelerated and at the same time cause the sucrose crystals to be normalized with the result that the sucrose is effectively separated in said sugar-boiling and centrifugal separation process and the amount thereof is increased.