Protein nanoemulsions are excellent carriers of nutrients due to their unique surface activity and structural properties, however, poor stability has limited their application. The Maillard reaction can enhance protein emulsification, but an excess of dextran formed during the reaction can trigger detrimental effect. In this study, the influence of unbound dextran following the Maillard reaction on nanoemulsions composed of bovine serum albumin (BSA) and dextran conjugates was studied. The results showed that saturation grafting occurred at a 1:7 M ratio of BSA to dextran during the Maillard reaction. Rheological analysis revealed that the relative amount of difference between the loss modulus (G″) and storage modulus (G′) in the nanoemulsions was most pronounced within the ratio of 1:7–1:11. This difference decreased when the dextran content exceeded 1:11, indicating a reduction in the system’s ability to prevent aggregation. Nanoemulsions within the range of ratios 1:7–1:11 showed no droplet aggregation, particle size, or zeta-potential alterations after 3-months of storage. They remained stable at 90 °C, with NaCl concentrations within 75 mM, and at pH 3–8. Small amounts of free dextran remaining from the Maillard reaction are deemed acceptable in subsequent nanoemulsions preparation. This study offers a scientific foundation for devising cost-effective strategies in industrial production.