In our present study, a model Maillard furfural/cysteine reaction was chosen for exploring and understanding the different aspects that control the reactivity in five-component fully dilutable U-type food-grade oil/water (O/W) microemulsions of R(+)-limonene/ethanol/water/propylene glycol/Tween 60. It was found that these self-assembled nanosized structured systems are capable of enhancing the rate of Maillard reactions in which the selectivity and the reactivity are controlled by the composition of the interface and its curvature. The sulfur-containing flavor formation is very efficient if carried out in those O/W microemulsions (modified oil-swollen nanoreactors) and the reaction yields high amounts of key aroma compounds. The proposed Tween 60-based O/W systems show strong preference for the formation of 2-(2-furanyl)-thiazolidine (the main product). The O/W reaction medium enhances furfural-cysteine reaction rate (microemulsion catalysis) in comparison to the water-based reaction. It was found that the initial reaction rate (V₀) is affected by the solubilized aqueous phase content. The furfural-cysteine reaction is affected also by the process conditions (temperature, pH, time of reaction). These results suggest that O/W microemulsions are a promising choice for generation of flavors and food products.