Designing Gel-Inspired Food-Grade O/W Pickering Emulsions with Bacterial Nanocellulose-Chitosan Complexes

Area of Science:

• Materials Science
• Food Science
• Biotechnology

Background:

• Pickering emulsions offer an alternative to traditional emulsions but require effective stabilizers.
• Chitosan (CH) and bacterial cellulose (BC) are biocompatible biopolymers with potential emulsifying properties.
• Developing sustainable, food-grade emulsifiers is crucial for the bioeconomy.

Purpose of the Study:

• To investigate chitosan (CH)/bacterial cellulose (BC) complexes as novel emulsifiers for oil-in-water (o/w) Pickering emulsions.
• To evaluate the gel-like behavior and stability of these CH/BC stabilized emulsions.
• To explore the impact of formulation variables and additives on emulsion properties.

Main Methods:

• Preparation of o/w Pickering emulsions using CH/BC complexes and sunflower oil.
• Characterization of emulsion stability using the emulsion stability index (ESI).
• Analysis of droplet size and zeta potential via dynamic/electrophoretic light scattering.
• Rheological analysis to determine gel-like properties (G' > G″).
• Investigation of pH, ionic strength, and protein isolate effects.

Main Results:

• CH/BC complexes enhanced emulsion stability, reduced phase separation, and increased viscosity.
• CH/BNC1_25:75 emulsions exhibited high stability (ESI up to 100% after 3 days) with stable droplet size (~8.5-8.8 μm).
• Emulsions displayed shear-thinning behavior and dominant elastic properties, indicating a soft gel network.
• Incorporation of sunflower-seed protein isolates formed coacervates, reducing droplet size and increasing zeta potential.

Conclusions:

• CH/BC complexes are effective and sustainable stabilizers for food-grade Pickering emulsions.
• The gel-like behavior of these complexes contributes to enhanced emulsion stability.
• These findings support the development of bio-based emulsifiers aligned with bioeconomy principles.