1-Butanol is a well-known biofuel for blending with both gasoline and diesel. It is also reported to act as fuel additive and convert straight vegetable oil (SVO) into a diesel blend. The direct use of SVO and 1-butanol in diesel blends has important implications for the elimination of transesterification of triglycerides. The mechanism of SVO stabilization in diesel in the presence of 1-butanol remains unknown. The present work describes the physicochemical properties and mechanism of stability of biofuel blends with 1-butanol as a fuel additive. The presence of 1-butanol as an additive results in a clear homogeneous fuel composition. The mechanisms of triglyceride stability in fuel blends with 1-butanol were studied with fluorescence techniques using the charge transfer probes Nile Red and PRODAN. We found that the micro-environment of biodiesel blends with 1-butanol results in the stabilization of triglycerides by formation of reverse micelles. The charge transfer probes displayed fluorescence emission peaks representative of the region in which they are present. We observed that the four regions present in AOT reverse micelles are also present in this 1-butanol/SVO/diesel ternary mixture. The physicochemical analysis including friccohesity has suggested that the formed reverse micelle is stable. This study is the first attempt to understand the mechanism behind stabilization of SVO as diesel blend in presence of 1-butanol. © 2018 Elsevier Ltd