In the quest for sustainable and eco-friendly solutions in the food industry, a groundbreaking study has emerged, offering a novel approach to stabilizing oil-in-water emulsions. Led by Antiopi Vardaxi from the Theoretical and Physical Chemistry Institute at the National Hellenic Research Foundation in Athens, Greece, the research explores the potential of chitosan (CH) and bacterial cellulose (BC) complexes as stabilizers for food-grade Pickering emulsions. Published in the journal ‘Gels’ (which translates to ‘Gels’ in English), this work could pave the way for more sustainable and efficient emulsification processes.
The study focuses on the gel-like behavior of these emulsions, which are crucial in various food applications, from dressings to beverages. Vardaxi and her team investigated the use of CH combined with bacterial nanocellulose (BNC) derived through different hydrolysis methods. They found that increasing the BNC content improved the stability of the emulsions by reducing phase separation and enhancing viscosity. “The key to our success was the synergistic effect of chitosan and bacterial nanocellulose,” Vardaxi explained. “Chitosan provided interfacial activity and electrostatic stabilization, while BNC enhanced the overall stability and gel-like properties.”
The researchers discovered that emulsions with a specific ratio of CH to BNC (25:75) exhibited the highest stability, maintaining an emulsion stability index (ESI) of up to 100% after three days. This stability was attributed to minimal changes in droplet size and a positive zeta potential, which indicates good electrostatic repulsion between droplets. The emulsions also showed remarkable resilience to pH changes, with little effect on their ESI when adjusted to pH 4 and 10.
Rheological analysis revealed that the CH/BNC emulsions exhibited shear-thinning behavior and dominant elastic properties, indicating a soft gel network. This gel-like structure is crucial for maintaining the stability and texture of food products. “The rheological properties of these emulsions are particularly exciting,” Vardaxi noted. “They mimic the behavior of natural gels, which is highly desirable in the food industry.”
The study also explored the incorporation of sunflower-seed protein isolates into the CH/BNC emulsions, leading to the formation of coacervates and a three-layer system. This innovation resulted in a decrease in droplet size and an increase in zeta potential over seven days, further enhancing the stability and potential applications of these emulsions.
The implications of this research are significant for the food industry, particularly in the development of sustainable and eco-friendly emulsifiers. By utilizing biopolymer-based complexes, the study aligns with the principles of the bioeconomy, promoting the use of renewable resources and reducing environmental impact. “Our findings highlight the potential of chitosan and bacterial nanocellulose complexes as sustainable stabilizers for food-grade Pickering emulsions,” Vardaxi stated. “This research supports the development of biopolymer-based emulsifiers that are not only effective but also environmentally friendly.”
As the food industry continues to seek innovative and sustainable solutions, the work of Vardaxi and her team offers a promising avenue for exploration. The use of gel-inspired, biobased emulsifiers could revolutionize the way emulsions are stabilized, leading to more efficient and eco-friendly processes. This research not only advances our understanding of polymer complexes but also opens new possibilities for the future of food science and technology.