Bacterial cellulose vs. bacterial cellulose nanocrystals as stabilizer agents for O/W pickering emulsions

The growing interest in Pickering emulsions in functional food systems resulted in the need to find suitable stabilizers for them. The work considers the use of bacterial cellulose for this purpose, and its aim was to compare the properties of disintegrated bacterial cellulose, before and after freeze-drying, and its nanocrystals obtained using H2SO4 under variable of time and concentration conditions. The structure of nanocrystals obtained with 30% acid was found to be still similar to that of parent cellulose, while the structure of nanocrystals obtained with 65% acid showed allomorphic transformation and the cellulose sulfates formation, regardless of the acid treatment time. Unlike nanocrystals obtained with 65% acid, those obtained with 30% acid as well as native bacterial cellulose ensured the high stability of O/W emulsion containing up to 20% olive oil. Effective stabilization of emulsions with the addition of nanocrystals obtained with the use of 30% acid was ensured by their strong surface charge density due to the presence of negatively charged sulfate groups.