title: Surfactant-free emulsions stabilized by tempo-oxidized bacterial cellulose.
abstract: In order to seek a safe, biodegradable, and sustainable solid stabilizer for food, topical and pharmaceutical emulsions, individualized cellulose nanofibers were prepared by oxidizing bacterial cellulose (BC) in a Tempo-mediated system; their ability to stabilize oil/water interface was investigated. Significant amounts of C6 carboxylate groups were selectively formed on each cellulose microfibril surface, so that the hydrophilicity was strengthened, leading to lower contact angles. Meanwhile, both the length and width of fibrils were decreased significantly, by partial cleavage of numerous numbers of inter- and intra-fibrillar hydrogen bonds. Tempo-oxidized BC (TOBC) was more effective than BC in stabilizing oil-water interface, attributing to the much smaller size. Fibril dosage and oxidation degree exerted a great influence on the stability and particle size distribution of emulsion samples. When the fibril dosage was 0.7wt.%, the sample was so stable that it did not experience creaming and coalescence over 8 months. The 2-TOBC coated droplets showed the greatest stability, although both the zeta potential and the electric repulsion were the largest for the 10-TOBC analogue, which was manipulated by the wettability of fibrils. In addition, the stability of samples was analyzed from the viewpoint of particle size distribution. Consequently, fibril size and wettability are two counterbalanced factors influencing the stability of TOBC-stabilized emulsions; a combination of suitable wettability and size imparts TOBC-stabilized emulsion high stability. As a kind of biomass-based particle stabilizer, TOBC showed great potential applications in food, topical and pharmaceutical formulations.
authors.affiliation: Key Laboratory of Industrial Microbiology, Ministry of Education, Tianjin University of Science and Technology, TEDA, Tianjin 300457, PR China; College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, TEDA, Tianjin 300457, PR China. Electronic address: jiayuanyuan55@hotmail.com.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Jia
authors.affiliation: College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, TEDA, Tianjin 300457, PR China. Electronic address: 312525235@qq.com.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Zhai
authors.affiliation: Cargill Food (Tianjin) Co. LTD., 29 Huashan Road, Hangu Modern Industrial Park, TEDA, Tianjin, PR China. Electronic address: fuwei0012@gmail.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Fu
authors.affiliation: College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, TEDA, Tianjin 300457, PR China. Electronic address: 1121950566@qq.com.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, TEDA, Tianjin 300457, PR China. Electronic address: nisida2888@hotmail.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Li
authors.affiliation: Key Laboratory of Industrial Microbiology, Ministry of Education, Tianjin University of Science and Technology, TEDA, Tianjin 300457, PR China. Electronic address: czhong@tust.edu.cn.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhong
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry; D002483:Cellulose, Oxidized / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry*; D004655:Emulsions; D041822:Gluconacetobacter xylinus / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry; D017155:Wettability
chemical_list: D002264:Carboxylic Acids; D002483:Cellulose, Oxidized; D003497:Cyclic N-Oxides; D004655:Emulsions; D013501:Surface-Active Agents; C003959:TEMPO
keywords: Bacterial cellulose; Emulsion stability; Particle size distribution; Pickering emulsion; TEMPO oxidation; Wettability