Improvement of oleofilm performance by regulating the composition and size of emulsion-based solid lipid particle dispersion

In this study, beeswax (BW)/soybean oil (SO) mixed lipid phase and bacterial cellulose nanofibrils (BCNF)/gelatin (GLT) hybrid stabilizers were utilized to prepare O/W emulsions, which were applied as templates to fabricate solid lipid particle (SLP) dispersion for further preparing oleofilms. As the BW content (based on lipid phase) increased from 10 to 40 wt%, the SLP size became smaller, and the obtained oleofilms showed significant variations in the structure that more lipid crystals distributed on the film surface and film exhibited increased crystallinity. The film prepared with SLP with 40 wt% BW (based on lipid phase) had the best light barrier property, largest contact angle (96 ± 1 o ) and lowest water vapor permeability (WVP, 4.4 ± 0.1 × 10 −8  g m −1 ·h −1 ·Pa −1 ), but the lowest tensile strength (1.53 ± 0.11 MPa) and elongation at break (2.32 ± 0.16%). The SLP dispersion was further ultrasonically treated (SLP-U) for improving the physical property of oleofilms. Compared to SLP oleofilms, SLP-U oleofilms possessed more uniform micro-structure, better transparency, and higher mechanical strength, revealing that SLP-U had higher adhesion with biopolymer matrix. The increase of BCNF ratio contributed to the significant decrease in the SLP-U size, improved the oleofilm contact angle, but reduced the film mechanical strength. This study provided the regulation method of acceptable barrier and mechanical properties for oleofilm by properly tailoring the lipid particle property.