Abstract:The complex emulsifiers with different HLB values were obtained by compounding Tween and Span.The effects of emulsifier HLB on the physical and structural properties of chitosan oil composite film were investigated.The results showed that a smaller particle size was obtained by the proportion of 1 ∶5 and 1∶10 between the single emulsifier and essential oil when HLB value was from 9 to 15.When the emulsifier was added into the chitosan essential oil composite film solution，the particle size of the film solution gradually decreased with the increase of the HLB value.Moreover，compared with the control film，the L*value of the film increased with the addition of emulsifier，the thickness，swelling and water solubility of film were reduced.But the effect of the emulsifier HLB value on the tensile strength and elongation at break of the film was little.Higher DPPH free radical scavenging rates were obtained with the HLB values from 11 to 15.From the results of scanning electron microscope，the particle size of the essential oil was significantly reduced with the added emulsifier in the composite film.In general，an optimized composite film could be obtained with the HLB value of 13.