Primary structure of gum arabic and its dynamics at oil/water interface

• Published in: Carbohydrate polymers Vol. 249; p. 116843
• Main Authors: Isobe, Noriyuki, Sagawa, Naoya, Ono, Yuko, Fujisawa, Shuji, Kimura, Satoshi, Kinoshita, Keigo, Miuchi, Takeshi, Iwata, Tadahisa, Isogai, Akira, Nishino, Masayuki, Deguchi, Shigeru
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-12-2020
• Subjects: 13C CP/MAS NMR; Colza oil; Dodecane; Dynamic interfacial tension; Emulsion; Gum arabic; SAXS; SEC-MALLS; Emulsion; Dynamic interfacial tension; Dodecane; Gum arabic; SEC-MALLS; Colza oil; 13C CP/MAS NMR; SAXS; C CP/MAS NMR
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2020.116843

•Structure-interfacial property relationship of gum arabic (GA) is studied.•Primary structure of GA is a disk-like star shaped nanoparticle.•GA molecules adsorb onto oil surface in 2 steps.•Emulsion stability is controlled by high-order molecular network.
Gum arabic (GA), an arabinogalactan-based gum, is a well-known powerful emulsifier. However, the poor stability of emulsion has often been pointed out. In order to clarify the origin, the structure-property relationship of GA, especially the interfacial property at oil/water interface, needs to be investigated. Here, we tried to correlate the primary structure with interfacial property at oil/water interface. A series of structural analyses by SEC-MALLS, SAXS, etc. showed that the primary structure of GA was a disk-like star shaped nanoparticle. The dynamic interfacial tension measurement showed that GA molecules adsorb onto oil surface in 2 steps: Firstly, the micron-aggregates of GA approach onto the oil surface, and then the aggregates are dissociated into nano-particles so that they cover the oil surface. Therefore, the emulsification and emulsion stability are controlled not by the property of the primary structure of GA but by the higher-order molecular network structure made of GA molecules.