Porous starch (PS) is known for high absorption capacity at temperatures below gelatinisation temperature however, it exhibits limited emulsifying capacity constraining its applications in emulsion-based food systems. Enhancing PS functionality is therefore essential for developing plant-based alternatives to conventional emulsifiers. This study investigated whether modified PS could function as a full or partial replacement for soy lecithin (SL) in high internal phase emulsion (HIPE) designed for egg-yolk free mayonnaise. Modified PS samples were prepared using physical pretreatments ultrasound (US); alcohol-alkaline treatment (GCWS) followed by controlled enzymatic hydrolysis with α-amylase and amyloglucosidase. The interaction between modified PS and SL at different concentration (1% - 3%) were examined in relation to interfacial, structural and rheological properties. The result indicated stable emulsion was formed at oil internal phase of 0.75 with particle concentration (1%wt) of SL:modified PS (50:50). Fourier transform infrared spectroscopy confirmed the formation of PS-SL complexes (US-PS-SL and GCWS-PS-SL) through hydrophobic interaction and hydrogen bonds. Addition of SL decreased surface tension of oil/water emulsion, enhanced the gel network strength and apparent viscosity and increased emulsion stability during storage. Modified PS alone was incapable of stabilising emulsions, but incorporation of low SL level markedly improved emulsion structure, indicating that modified PS can partially replace lecithin without compromising its performance. Among the systems studied, US-PS-SL showed network rigidity which improved stabilisation and resistance to coalescence compared to GCWS-PS-SL.Overall, the findings highlight the potential of modified PS as a natural structuring agent capable of reducing and in some cases substituting, lecithin in HIPE based mayonnaise. This work provides mechanistic insight into starch-lecithin interactions and offers new opportunities for developing egg-yolk-free emulsions using plant-derived co-emulsifier systems.