High-moisture extrusion of rice bran-peanut proteins: Changes in structural properties and antioxidant activity simulating gastrointestinal digestion

In this experiment, we investigated the structural properties, digestibility, and variations in antioxidant activity of rice bran-tissue peanut protein (RB-TPP), which was created through high-moisture extrusion between peanut protein powder (PPP) and various additions (0 %, 5 %, 10 %, 15 %, and 20 %) of rice bran (RB). The disulfide bonding and hydrophobic interactions were strengthened, and the hydrogen bonding in the RB-TPP was weakened by adding 5-10 % RB. Additionally, the β-sheet content reached its maximum at RB-10 %, which allowed the hydrophobic groups to be encapsulated ina stable protein network fiber structure, enhancing degree of organization, the thermal stability and digestibility of RB-TPP. On the other hand, RB-10 % showed increased total phenolic content and antioxidant activity, in which the ABTS radical scavenging rate was increased by 22.14 % compared with that of RB-0 %, while the DPPH radical scavenging rate in simulated gastric digestion was increased by 10.59 %. RB addition at 15-20 % hindered the aggregation of proteins, which was not conducive to the rearrangement of protein molecules, and the increase in the irregular curls made the RB-TPP structure loose and disordered. This study provides valuable information for producing tissue proteins with stable fiber network structure and better nutritional and functional properties by adding RB.