Nanocellulose for Stabilization of Pickering Emulsions and Delivery of Nutraceuticals and Its Interfacial Adsorption Mechanism

Abstract

Nanocellulose proved to be an efficient material for the preparation of Pickering emulsions with potential for replacing synthetic surfactants, which show toxic effects in the gastrointestinal (GI) tract. Its self-assembling capability, tensile strength, and stiffness make it an efficient material for stabilization of emulsions. Nanoemulsion systems stabilized with nanocellulose (NC) can be prepared for delivery of nutraceuticals with therapeutic utilities and achieving their controlled release in the GI tract. Stable emulsions can be produced even when the surface of droplets is covered by a low amount of NCs. Hydrophobic modification of NCs enhances their dispersibility in nonpolar solvents, and modification with cationic surfactants enables the production of emulsions with transitional phase inversion and production of water-in-oil emulsions. Grafting NCs with responsive polymers provides the opportunity of producing smart emulsifiers for delivery of nutraceuticals. The adsorption of NCs at the interfaces is influenced by their surface chemistry and charge and the emulsion conditions such as pH, temperature, and ionic strength. Their adsorption can be explained based on particle diffusion to the interface and charge-induced kinetic adsorption barrier. Modification of NCs allows achieving faster adsorption and higher surface pressure and surface coverage. Considering the economic and environmental benefits of NCs in replacing nonrenewable materials and their potential in producing stable Pickering emulsions, this review aims to highlight recent studies on the application of NCs for stabilization of Pickering emulsions and delivery of nutraceuticals, and discusses their interfacial adsorption mechanism, influenced by processing conditions, providing insights to food and drug manufacturers.