The objective of this study was to develop a new emulsifier that possesses antioxidant properties and is prepared from naturally occurring compounds. The emulsifier was synthesized by combining oleic acid, gluconic acid, and quercetin. Mango kernel was chosen as a source of oleic acid due to its cost-effectiveness and high oleic acid content. The process involved grinding and drying the kernels, followed by extracting the oil using a Soxhlet device. The extracted oil was further examined to determine its physical and chemical properties, as well as its fatty acid composition. After that, the oil was hydrolysed, producing a mixture of free fatty acids and glycerine, which were then separated from each other. Oleic acid was extracted individually in pure form from the fatty acid mixture using a supercritical CO2 extractor at 28.0 MPa, 313 K. And it was confirmed according to its physical, chemical and spectral characteristics. Oleic acid was then converted to 9-hydroxyoctadecanoyl chloride, followed by its reaction with quercetin and gluconic acid through several steps to produce a novel antioxidant emulsifier known as 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4-oxo-4H-chromen-3-yl9-((2,3,4,5,6-pentahydroxyhexanoyl)oxy)octa-decanoate or as chromenyl gluconyl octadecanoate for simplification. The structures of all prepared compounds were elucidated according to their elemental analysis and spectral data (IR, 1H NMR, 13C NMR and MS). The radical scavenging activity of the newly prepared compound was evaluated using DPPH and ABTS methods, as well as lipid oxidation in sunflower oil with a Rancimat apparatus. The results indicated good antioxidant activity. The compound's surface-active properties and emulsion stability were tested, soy lecithin was used as a reference compound, and the results indicated its efficacy as a surfactant. Albino mice were used for an acute oral toxicity test, with subsequent examination of their liver and kidney functions. The results indicated no significant changes, confirming the safety of the prepared compound. The newly prepared antioxidant emulsifier was used to produce a blend fat spread. This is a typical example of how it can be used. The texture and sensory properties of the spread were evaluated, and the results showed that the properties of the blend fat spread were significantly improved with the use of new antioxidant emulsifier