Selection of Antioxidant Peptides from Gastrointestinal Hydrolysates of Fermented Rice Cake by Combining Peptidomics and Bioinformatics

Separation of antioxidant peptides from complex food matrix is labor-intensive and time-consuming. The combination of peptidomics and bioinformatics may shorten this process. In this work, the gastrointestinal hydrolysates of fermented rice cake (FRC) were roughly separated by routine methods. Then, bioinformatics was applied, and two peptides (P1, WLSYPMNPATGH; P2, PRPPKPDAPR) were selected based on their predicted antioxidant activities. The two peptides were then synthesized, with P1 showing DPPH radical scavenging activity, hydroxyl radical scavenging ability and ferric chelating ability and with P2 showing no DPPH scavenging ability. Molecular docking between DPPH and P1 or P2 showed possible hydrogen bonds between DPPH and the two peptides. Considering the low hydrophobicity of P2 and its possible bonds with DPPH, the importance of hydrophobicity in affecting DPPH scavenging activity of P2 was revealed. This study for the first time showed the adaptability of using peptidomics and bioinformatics in functional peptide selection in FRC.