Provided is a use of an α-glycosidase capable of acting on a saccharide selected from the group consisting of α-type oligosaccharides and α-type polysaccharides to produce a saccharide having contiguous α-1,6 bonds in the production of a food or a beverage by processing a polysaccharide-containing raw material. Also provided are: a method for improving a food or a beverage, said method comprising using the α-glycosidase and an improving agent for a food or a beverage, said improving agent comprising the α-glycosidase. It is found that an α-glycosidase occurring in Aspergillus sojae, which is one of bacteria belonging to the genus Aspergillus, has a high activity of producing a saccharide having contiguous α-1,6 bonds, it is also found that a food or a beverage each produced using the α-glycosidase is good in texture even when cold and the texture of the food or the beverage can be kept good during storage, and it is also found that the α-glycosidase has high heat resistance.
