Formulation effects on the enhanced structural and anti-oxidative properties of emulsions stabilized by complexes of cellulose nanofibrils (CNF) and epigallocatechin gallate (EGCG)

Abstract

In this study, the effect of cellulose nanofiber (CNF)-epigallocatechin gallate (EGCG) complexes on the stability of emulsions was examined through analysis of their microstructure and rheological behavior as a function of the CNF- EGCG complex concentration (w, 0.6–1.4 %, w/v) and oil phase volume fraction (φ, 0.2–0.8, v/v). Emulsions with smaller droplet sizes were prepared by increasing the concentration of particles or the suitable oil phase (φ = 0.6). Microstructural analysis showed that the CNF-EGCG complexes stabilized the oil-water interface, while excess complexes formed a network structure in the continuous phase. Rheological analysis demonstrated that increasing either the oil phase volume fraction or the particle concentration enhanced the gel strength of the emulsion, thereby reducing oxygen-oil contact and droplet aggregation, ultimately improving the oxidative and physical stability of the emulsions. The structural disintegration of the emulsions was analysed by cross-strain (γ_co) determination. As the oil content increased, γ_co remained unaffected by the CNF concentration. In conclusion, our results showed that the properties of CNF-EGCG stabilized emulsions can be regulated by controlling the CNF concentration and oil phase volume fraction, offering important insights for the introduction of innovative new food products.