Rheology and stability mechanism of pH-responsive high internal phase emulsion constructed gel by pea protein and hydroxypropyl starch

[Display omitted] •High internal phase emulsion (HIPE) gel properties are modulated by pH.•High internal phase emulsions have the highest viscoelastic properties at pH 3.•Hydroxypropyl starch enhanced the strength of HIPE gels.•HIPE gels had the best physical stability and 3D printing capability at pH 11.•Hydrophobic interaction or electrostatic interaction was the main molecular force. There is an increasing demand for stable, highly viscoelastic, and printable emulsion gels based on pea protein (PeaP) as a substitute for animal fat. In this article, a simple pH modulation strategy was applied to regulate high internal phase (HIPE) gels prepared from PeaP and hydroxypropyl starch (HPS). The results showed that the interfacial tension of PeaP decreased from 11.9 to 7.1 mN/m at 5% PeaP and from 9.9 to 6.3 mN/m at 10% PeaP with increasing pH from 7 to 11. The incorporation of HPS improved the strength and physical stability of the HIPE gel. HIPE gels showed the best three-dimensional printing ability at pH 11. The main mechanism of HIPE gels at pH 3 was hydrophobic interaction, while electrostatic interaction dominated at pH 7, 9, and 11. This study may provide insights into the development of PeaP-based HIPE gels as a printable fat alternative.