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 a second batch of α-amylase into the reaction mixture and incubating for a further about 12-16 hours at about 55-95° C.;
• inactivating the second batch of α-amylase in the reaction mixture by low pH heat treatment;
• and
• removing impurities from the reaction mixture by contacting the reaction mixture with macroporous adsorbent resin and subsequently eluting adsorbed diterpene glycosides with aqueous ethanol to result in a purified reaction mixture;
• wherein the purified reaction mixture comprises α-1,4-glucosyl derivatives, and unmodified steviol glycosides.