The embeddedness of bioactive molecules: structural characterization and functional analysis of almond...

Adding specific stabilizers can improve the water solubility, stability, and antioxidant activity of phloretin (PHL) and almond protein (AP). This study utilized hydroxyl radicals generated by the ascorbic acid-H₂O₂ reaction system. Firstly, AP was made to form a macroradical and then covalently bound to PHL to form an AP-PHL binary complex. In addition, L arabinose (LAR) was introduced to construct the AP-PHL-LAR ternary complex. The results showed that compared with AP-PHL, the scavenging rate of AP-PHL-LAR on ABTS and DPPH free radicals increased by about 3.81 % and 10.42 %, respectively. In the middle and late stages of simulated gastrointestinal digestion, the ABTS scavenging rate of the two complexes was >70 %, and the DPPH scavenging rate was >60 %, which still had high antioxidant properties. In addition, PHL significantly improved its water solubility by covalent binding. The ultraviolet, fluorescence, Raman, and Fourier transform infrared spectroscopy results showed that the hydrophobic groups migrated to the hydrophilic environment after AP and PHL covalent binding. LAR binds to AP-PHL by non-covalent interactions such as hydrogen bonds and hydrophobic forces. PHL increased the α-helix content of AP by about 26.81 % and decreased the contents of β-sheet and random coil by 12.46 % and 8.46 %, respectively, while the addition of LAR had no significant effect on this. LAR can use hydrogen bonds and hydrophobic forces to reduce the gap between the complexes and improve the integrity of the overall structure. This study not only improves the stability and functionality of PHL but also provides new ideas for developing new functional protein foods, which is expected to help the food industry develop healthier and more efficient products.