Novel steviol glycoside, method for producing same, and sweetener composition containing same

The purpose of the present invention is to determine the structure of a novel steviol glycoside that is detected in breeds containing an abundance of Reb.C (also called dulcoside B) and that affects the quality of taste in a small amount, and to identify the quality of taste properties. According to the present invention, a compound represented by formula (1), or a derivative, salt, or hydrate thereof is provided.