Highly stable, controllable, and antibacterial nanocellulose-stabilized aroma emulsions via interfacial self-assembly strategy

Abstract

The nanocellulose-stabilized aroma emulsions have the potential to replace surfactant-stabilized emulsions. However, the stability of aroma emulsions stabilized by nanocellulose still remains a challenging task. Herein, we developed a stable nanocellulose-stabilized aroma emulsion with controllable and antibacterial properties through cellulose nanocrystal (CNC) and NH2-PDMS-NH2 self-assembly at the oil-water interface. The stability, interfacial behavior, rheological and antibacterial properties of the emulsion were investigated. Our results reveal that the creaming index of the emulsions remained almost unchanged even after being stored for one week. The interfacial tension between the CNC aqueous phase and limonene decreased from 20.5 to 8.5 mN/m, as the addition of NH2-PDMS-NH2 (20 mg/mL). Notably, the interface tension (ranging from 3.5 to 11.1 mN/m) and the interfacial coverage rate of the CNC at the oil/water interface (ranging from 68.6 % to 97.5 %) could be tune by adjusting the pH value of the aqueous phase. The storage modulus and viscosity of the emulsions increased as the concentration of NH2-PDMS-NH2 increased. The aroma emulsion was highly stable under the conditions of 1.5 wt% CNC, 10 mg/mL NH2-PDMS-NH2, the oil/water ratio of 1/9, and the aqueous phase pH of 3. Moreover, these emulsions exhibited significant resistance to Escherichia coli and Staphylococcus aureus. Overall, this research provides a method to prepare a stable nanocellulose-based aroma emulsion, which could extend the application area of aroma emulsion.