Application of Nanocellulose as particle stabilizer in food Pickering emulsion: Scope, Merits and challenges

Particle-stabilized emulsions, referred as Pickering emulsions (PEs), have been widely explored due to their potential practical interest in last few years. As a sustainable alternative for conventional stabilizers, food-grade colloidal particles have exhibited excellent performance in the formulation of novel Pickering emulsions. Among the natural biomacromolecules, cellulosic resources have attracted extensive attention due to their techno-functional, economic, renewable and non-toxic characteristics. In this article, the central point is on the clarification of nanocelluloses with different properties and the fundamental stabilization principles of the nanocellulose-based PEs. Ultimately, the applications of nanocelluloses-based PEs in food industry are described. Compared with the traditional emulsion, Pickering emulsion has better interface stability, non-toxic and harmlessness, and is not easily affected by the environment. This review focuses on the fabrication and mechanism of food-grade PEs stabilized by using nanocelluloses, especially for cellulose nanofibrils (CNFs), and bacterial cellulose nanofibrils (BCNFs). Nanocelluloses can be prepared by various green modifications, such as high-pressure homogenization (HPH), enzymatic hydrolysis, and sonication. Because of its wide range, degradable, renewable and strong stability, nanofibers have become a research hotspot in the preparation of Pickering emulsion. The obtained nanocellulose has been confirmed to effectively stabilize PEs via the irreversible adsorption into the oil-water interfaces and the formation of three dimensional networks between the droplets. These nanocellulose-based PEs systems are currently gaining an increasing demand in the fields of three-dimensional printing technology, targeted delivery systems and food package materials, which is extremely crucial for practical applications in food-grade products.