Glucosyl stevia composition

A process for producing a highly purified glucosyl stevia composition, comprising the steps of:

• adding starch into water to form a starch suspension;
• adding a mixture of α-amylase and CGTase into the starch suspension and incubating for about 0.5 to 2 hours at about 75-80° C., resulting in a liquefied starch suspension;
• inactivating the α-amylase by low pH heat treatment;
• cooling the liquefied starch suspension and adjusting the pH to about 5.5 to 7.0;
• adding steviol glycosides into the liquefied starch suspension, resulting in a reaction mixture;
• adding a second batch of CGTase into the reaction mixture and incubating for about 12 to 48 hours at about 55-75° C.;
• adding β-amylase to reaction mixture and incubating for about 12-24 hours at about 35-55° C.;
• inactivating the enzymes in the reaction mixture by heat treatment;
• decolorizing the reaction mixture;
• removing non-diterpene compounds by contacting the decolorized reaction mixture with macroporous adsorbent resin and subsequently eluting adsorbed diterpene glycosides with aqueous ethanol to result in a glycoside-containing aqueous ethanol eluate;
• desalting the glycoside-containing aqueous ethanol eluate with ion-exchange resins;
• removing ethanol from the aqueous ethanol eluate, resulting in an aqueous eluate;
• concentrating and drying the aqueous eluate to obtain the dried glucosyl stevia composition,
• suspending the dried glucosyl stevia composition in aqueous alcohol to form a suspension, removing unmodified steviol glycosides from the suspension, and separating and drying the highly purified glucosyl stevia composition;
• wherein the highly purified glucosyl stevia composition comprises short-chain steviol glycoside derivatives having two or less α-1,4-glucosyl residues, and less than about 15% unmodified steviol glycosides.