Isomaltooligosaccharides in Sikhye were digested with enzyme (30unit/ml) of $alpha$-amylase, $alpha$-glucosidase and glucoamylase from Aspergillus awamori, sweet potato $eta$-amylase and human salivary $alpha$-amylase at 37$^{circ}C$ for 1 hour, respectively. These amylases acted on these saccharides to give hydrolysis products with less than 20% of degree of hydrolysis, except the case of glucoamylase with 62% of high degree of hydrolysis. $alpha$-Glucosidase plus human salivary $alpha$-amylase hydrolyzed it to attain the hydrolysis value up to 25%, but further increment of hydrolysis was not observed. Rice residue in Sikhye has similar sugar composition and structure, judging from sugar analyses by the enzymatic hydrolysis. These results suggest that isomaltooligosaccharides and rice residue in Sikhye can be a growth factor for Bifidobacterium and dietary fiber which is useful for human health.