Despite constituting roughly one-third of wood biomass, hemicelluloses have received less attention compared to cellulose and lignin. Such lack of spotlight has largely been attributed to the difficulty in understanding their behaviour, considering that different sources, extraction methods, and post-extraction treatments lead to a high level of structural complexity of the hemicelluloses. However, their complexity also gave rise to their functionality, as in the case of hemicelluloses extracted by pressurized hot water extraction (PHWE). On one hand, these extracts contain a higher amount of residual lignin compared to those of other extraction methods, which proved to be essential in enhancing the emulsion stabilizing capability of these hemicelluloses. On the other hand, this presented a hurdle in product applications as they impart perceivable brown colour and woody flavour, which can be undesirable for some products.  By studying the interfacial properties of PHWE-extracted glucuronoxylans (GX) from birch, we aimed to understand the contributions of the polysaccharide and lignin fractions towards the emulsion stabilization mechanism. We have found that the polysaccharide fraction constructed the bulk of the interfacial layer, while their adsorption was enabled by the lignin fraction; the thickness of the interfacial layer was not affected by the ratio between polysaccharide and lignin. The polysaccharide fraction mainly pointed towards the aqueous phase, while the lignin fraction to the oil phase. Both fractions contributed to emulsion stabilization primarily through electrostatic repulsion; however, excessive lignin in the form of adsorbed insoluble particles destabilized emulsions by promoting bridging flocculation, particularly at low pH. Our results indicated the possibility of tuning the emulsifying capability of wood hemicelluloses extracts by adjusting their proportion of polysaccharide and lignin, providing a scientific basis in choosing the refining approach of wood hemicelluloses based on the properties of the desired emulsion-based products.