# 3D Printability of Lysine-Modified Myofibrillar Protein Emulsions

## TL;DR

This study shows that lysine-modified fish protein can stabilize emulsions for high-quality 3D printing.

## Contribution

Lysine modification enhances the 3D printability of myofibrillar protein-stabilized HIPEs.

## Key findings

- Lysine-MP interactions are driven by hydrogen bonding and electrostatic forces.
- Lysine improves HIPE viscoelasticity and print accuracy up to 91.36%.
- Lysine reduces droplet size to 10.84 μm, enabling stable 3D printable inks.

## Abstract

This study explores the potential of lysine (Lys) and tilapia myofibrillar protein (MP) composite particles in the formulation of highly inwardly directed emulsions (HIPEs). Infrared spectroscopy, potentiometric analysis, and molecular docking studies revealed that the interaction between Lys and MP is primarily governed by hydrogen bonding and electrostatic forces. The incorporation of Lys significantly influenced the particle size, secondary and tertiary structures, solubility, and turbidity of MP. Lys-MP-stabilized HIPEs can form highly stable denser self-supporting gel network structures. Rheological analysis of HIPEs stabilized by MP showed a low energy storage modulus (G’ 110.66 Pa) and water–oil separation, therefore preventing 3D printing. However, HIPEs stabilized by Lys (especially 1.5 wt%) significantly improved the energy storage modulus (G’ 1002.10 Pa), increased viscoelasticity and thixotropic recovery, and reduced droplet size (10.84 μm), facilitating the use of HIPE inks for 3D printing. Furthermore, HIPEs stabilized with 1.5 wt% Lys-MP demonstrated superior print accuracy (91.36%), resolution, and clarity in 3D printing applications. Overall, these findings offer a promising strategy for developing Lys-MP composite particle-stabilized HIPEs tailored for advanced 3D printing technologies.