Fabrication of ferulic acid-soybean protein isolate complexes for high internal phase emulsions: Interaction mechanisms and 3D printing.

In order to advance the development of 3D printed personalized food products and to understand the printability and potential mechanisms of high internal phase emulsions (HIPEs), this study innovatively stabilized HIPEs with a ferulic acid-soy protein isolate (FA-SPI) complex and evaluated the applicability of FA to HIPEs 3D printing technology. Multiple spectroscopic methods were used to ascertain that FA induced a fluorescence burst in SPI. The microenvironment of SPI amino acids was changed, inducing secondary structural changes in SPI, such as reduced α-helix and increased β-sheet content. The outcomes of molecular docking and molecular dynamics simulations elucidated that FA bound to SPI mainly through hydrogen bonds and hydrophobic interactions. Moreover, proteins' functional characteristics showed a trend of rising and then falling in the range of SPI/FA mass ratios from 10:1 to 2:1. At an optimal SPI/FA ratio of 6:1, the functional properties of the complex were significantly improved. The ABTS scavenging ability (72.36 %), emulsifying activity (50.17 m2/g), and solubility (30.72 %) exceeded those of native SPI by >50 %. Rheological, LF-NMR, and textural approaches were utilized to analyze the properties of FA-SPI-stabilized HIPEs. The results showed that the incorporation of FA endowed HIPEs with excellent shear thinning performance, high mechanical strength (G' > G"), and accurate shape fidelity, which could be used for 3D printing of complex structures. These findings provided a structure-function-application framework for HIPE in personalized 3D printing, expanding the diversity of materials for food 3D printing.