Abstract:

Protein-based films are of poor mechanical and water vapor-barrier properties. In order to solve this problem,a novel gelatin-olive oil emulsion film was prepared via the microfluidic emulsification technique. Then,the effects of homogenization on the particle size distributions of emulsions and the physical properties of the films were analyzed,and the correlations between the lipid droplet distributions and the mechanical as well as water vapor-barrier properties of the films were discussed. In addition,the controlled release properties of the films to lysozyme were also investigated. The results show that ( 1) when the emulsion is dispersed at a high rate,the lipid droplet is of large and unevenly-distributed particle size,and the corresponding film is of poor mechanical property,with a bi-layer-liked protein-lipid structure occurring during the forming of the film due to the enrichment of partial oil phase on the film surface; ( 2) when the emulsion is treated by means of microfluidization,it is in nano-scale with a concentrated particle distribution,and the corresponding film is of evenly-distributed oil phase and excellent tensile strength; ( 3) as compared with the control,the emulsion films obtained through the two above-mentioned homogenization techniques both have better water vapour-barrier property,although the corresponding mechanisms are different; and ( 4) the film prepared through microfluidization possesses excellent mechanical and water vaporbarrier properties as well as good controlled release ability to lysozyme.

Key words: emulsion film, microfluidization, microstructure, physical property, controlled release property