Structural properties and antioxidant activities of zein during in vitro simulated gastrointestinal digestion: Focus on effect of corn post-ripening

The aim of this study is to regulate the digestion degree of zein and the antioxidant activity of digests through post-ripening of corn. The effect of post-ripening of corns (Jidan 66 and Liangyu 99) on structural properties and antioxidant activities of zein during in vitro simulated gastrointestinal digestion was investigated. The results showed that zein had the highest digestion level after appropriate post-ripening of corn, such as storage at 25 °C for 28 days, which reduced molecular weights of zein digests and increased the content of peptides with molecular weight less than 1,000 Da. The post-ripening resulted in more unfolded and looser structure of zein digests, lowering particle size and enhancing surface charge. The high digestion level, low molecular weight, flexible structure and smaller particle size of protein facilitated the enhancement of radical scavenging capacities of zein digests after the corn post-ripening. Therefore, post-ripening of corn can be used to control the digestion degree of zein and the structure of digests, thereby enhancing their antioxidant activities, which was beneficial to improve digestion and functional activities of zein-based foods. • Zein had the highest digestion level after appropriate post-ripening of corn. • More peptides with molecular weight less than 1,000 Da were formed by post-ripening. • Post-ripening resulted in more disordered and looser structures of zein digests. • Post-ripening lowered particle size and enhanced surface charge of zein digests. • Radical scavenging capacities of zein digests were enhanced by post-ripening.