A strategy to improve 3D printing performance: Interaction between epigallocatechin gallate (EGCG) and honey bee pupa protein (HBPP)

Regulating protein structure with polyphenols was deemed an effective strategy for developing innovative foods with desirable physicochemical properties. Our previous research found that honey bee pupa protein (HBPP) gel exhibited good fluidity but poor structural stability, limiting its application in 3D printing. Therefore, epigallocatechin gallate (EGCG), a main component of tea polyphenols, was used to modulate the structure of HBPP, leading to the enhancement of the physicochemical properties of the HBPP gel. Among the evaluated HBPP-EGCG gels, those with an EGCG addition of ≥2% demonstrated the best printing performance. The results showed that compared to the HBPP gel alone, the HBPP-EGCG composite gel was more structurally stable, but the extrusion properties were not altered. This can probably be attributed to the fact that EGCG led to the aggregation behavior of HBPP, which resulted in a stronger gel network. At the protein conformational level, the addition of EGCG strengthened the hydrogen bonds of HBPP, facilitating the transition of HBPP from ordered structures (β-sheet and α-helix) to disordered structures (random coil and β-turn), while weakening hydrophobic interactions. The microstructural evolutionary mechanism of EGCG action on HBPP was proposed based on these findings, offering insights into the modification of protein gels for 3D printing applications.