Properties of Emulsion Co-Precipitated Collagen/Bambara Groundnut Protein-Based Film as Influenced by Basil Essential Oil and Soy Lecithin

Protein-based films have gained attention due to their potential as biodegradable packaging. This study investigated the properties and characteristics of film-forming emulsions (FFEs) and their films based on co-precipitated protein (CPP) from Bambara groundnut protein isolate (BGPI) and acid-soluble collagen (ASC) emulsified with different levels of basil essential oil (BE) (50%, 75% and 100%) and soy lecithin (SL) (25% and 50%). The oil droplet size, stability, and distribution of FFEs were characterized. Larger oil droplet sizes, a higher flocculation factor, and a higher coalescence index were observed for FFEs emulsified with higher levels of BE and SL. All FFEs had uniform oil distribution. Films from different FFEs were formed and analyzed. Films containing BE and SL had higher thickness, elongation at break, <i>b</i>*-value, water vapor and UV-light barrier properties, but a lower tensile strength than the control film. Emulsion films exhibited smooth surface and rough cross-section and were heat-sealable. FTIR spectra indicated lower protein interactions in the emulsion film containing higher levels of BE and SL. The film containing 100% BE had the highest antioxidant activities, regardless of the SL level used. The emulsification of BE and SL at various levels thus influenced the properties and characteristics of the FFE and emulsion film.