The invention relates to a process for extracting
rebaudioside C in
stevioside, comprising the following steps: (1) taking 1-3 kg of 60-70 percent of total
glucoside containing 19-25 percent of
rebaudioside C and 8-10 percent of
rebaudioside A, dissolving with 20-60 L
purified water to prepare 5 percent of
sugar liquor, desalting and decolouring by
ion resin, absorbing by absorbent resins, desorbing 70 percent of
alcohol water solution, desalting and decolouring by
ion resins, finally adding 0.2 percent of
active carbon by liquid weight, stirring, decolouring, condensing and
drying into
powder to obtain 0.75-2.22 kg of 85 percent of total
glucoside containing 25 percent of
rebaudioside C and 10-12 percent of
rebaudioside A; (2) adding 6-18.6 L of mixed
alcohol into a substance crystallizing tank, wherein the
methanol accounts for 30 percent and the
ethanol accounts for 70 percent, then placing 0.75-2.22 kg of products in the step (1), stirring and rising the temperature to 40 DEG C, preserving the temperature for 10 hours, filtering
mother liquor,
drying and
grinding the
filter cake to obtain 0.19-0.56 kg of products, placing the products in the crystallizing tank, adding 0.57-1.7 L of
methanol, stirring and reflowing, and then separating
crystal from
mother liquor to obtain the product containing above 95-97 percent of rebaudioside C after
drying. The invention has simple process and remarkable effect.