Encapsulation of cinnamaldehyde with protein-based nanoemulsions for strawberry preservation: Influence of protein types

This study investigated the encapsulation of cinnamaldehyde with three types proteins (soy 7S, whey protein and sodium caseinate) for strawberry preservation, and illustrated the related mechanism of the sustained release ability of CA-loaded nanoemulsions from the perspective of protein-cinnamaldehyde interactions. The results of FTIR, intrinsic fluorescence, and molecular docking indicated that the dominant interactions between the protein and cinnamaldehyde were mainly hydrophobic interaction and hydrogen bonds, of which, the interaction between cinnamaldehyde and SC was the strongest with the highest binding energy. The particle size of CA-loaded nanoemulsion formed by SC was the smallest (296 nm), but its release rate of cinnamaldehyde was the slowest. These results indicated that the exchange rate of bioactive compounds in nanoemulsion with the external environment was not only affected by the size of droplets, but also strongly affected by the interaction between bioactive compounds and interfacial proteins. A slowly release rate of cinnamaldehyde represented sustained antimicrobial activity. However, in practical preservation applications, not only the type of antibacterial agent and wall material should be considered, but also the influence of the concentration of antibacterial agent released in the environment should be taken into consideration. • Binding with CA could greatly alter the structural properties of protein. • The interaction between CA and SC was the strongest with highest binding energy. • SC-CEON had the smallest particle size but showed the slowest release rate of CA. • The CA-loaded nanoemulsion exhibited enhanced antibacterial and preservation effect.