Enhanced O/W emulsion stability and betanin protection using yeast protein and chitooligosaccharide: Comparative insights from complex coacervation and layer-by-layer methods

Emulsions play a pivotal role in food and related industries, yet oil-in-water (O/W) emulsions, a staple emulsion, are plagued by instability issues like aggregation, flocculation, and gravitational separation during storage. Stabilizing these emulsions has often involved the use of proteins or polysaccharides. Within this context, this research delves into comparing two distinctive stabilization strategies for emulsions. The yeast protein (YP), chitooligosaccharide (COS), and betanin were employed to formulate a complexation emulsion (CE) using a complex coacervation method, and a bilayer emulsion (BE) through a layer-by-layer method. The effects of these divergent methods on the emulsion's physicochemical properties, microscopic structure, and the stability of betanin was assessed. The findings indicate that the yeast protein-chitooligosaccharide-betanin (YCB) emulsion prepared using the layer-by-layer method demonstrated the smallest droplet size and the greatest absolute zeta-potential. After a storage period of seven days, this emulsion showed the lowest emulsification index, indicating excellent storage stability. In tandem, an increase in apparent viscosity was observed, with the emulsion exhibiting weak gel-like behavior. The incorporation of betanin has improved the physical stability of emulsions, and concurrently, the emulsion presented an improved storage stability of betanin. These results provide insightful perspectives for the development of emulsions based on bilayer interfaces, contributing to the expansion of novel fungal protein applications in the fields of emulsion technology, food processing, and the stabilization of bioactive molecules.