To understand the susceptibility of glutinous rice starch to digestive enzymes and its potential impact
on glycemic response, enzyme kinetics and in vitro digestibility of the native and gelatinized starches
were investigated. The results showed that the Km values of the native and gelatinized starch were
10.35 mg/mL and 9.92 mg/mL, respectively. The digestion rate coefficients k values of the native and gelatinized
starches were 2.0 × 10−3 min−1 and 1.1 × 10−2 min−1, respectively. The contents of rapid digestible
starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) in native glutinous rice starch were
8.92%, 21.52% and 69.56%, respectively. After gelatinization, the amounts of RDS, SDS and RS were 18.47%,
29.75% and 51.78%, respectively. The native and gelatinized glutinous rice starches were 10.34% and
14.07% for hydrolysis index (HI), as well as 43.14% and 45.92% for glycemic index (GI), respectively. During
the in vitro digestion, the crystallinity of native glutinous rice starch was increased from 34.7% to
35.8% and 38.4% after 20 and 120 min, respectively.