Glutelin and prolamin, different components of rice protein, exert differently in vitro antioxidant activities

•Glutelin and prolamin are two major components of rice protein (RP).•Prolamin is indigestible and nutritionally inferior to glutelin.•Glutelin and prolamin differently induce in vitro antioxidant response.•Glutelin exerts more excellent antioxidant capacity than prolamin.•The digestibility is a critical factor to modify antioxidant abilities of RPs.

Glutelin (RPG) and prolamin (RPP), with different digestibility, are two major components in rice protein. The major aim of this study was to elucidate whether different components of rice protein, RPG and RPP, could differently exert the in vitro antioxidant activities. Upon pepsin-pancreatin digestion, RPG exhibited stronger antioxidant responses to free radicals scavenging activities, metal chelating activities and reducing power, whereas weaker antioxidant capacities were produced by RPP. The present study firstly demonstrated that RPG and RPP could induce differently in vitro antioxidant response in the in vitro gastrointestinal tract, dependent on different degree of pepsin-pancreatin digestion. With better digestibility, RPG exhibits more excellent antioxidant capacity than RPP. Results suggest that the digestibility is a critical factor to modify antioxidant ability of rice protein and RPG might play a dominant role in inducing antioxidant response to rice protein.