Pickering emulsion stabilized by linear dextrins: Effect of the chain length

The objective of this study was to estimate the application of linear dextrins (LDs) as a potential emulsion stabilizer. LDs fractions with different chain length distributions were prepared by hydrolyzing amylose with α-amylase and graded in water. The physicochemical properties of the LDs were investigated. With the decrease of chain length, the contact angle of water drops on LDs plates increased from 48.10° to 54.20°, the surface tension decreased from 57.87 to 48.18 mN/m. The adsorption dynamics of LDs at the oil - water interface was also determined, the diffusion (kdiff), penetration (kpen) and rearrangement (krea) rate constants results manifested that LDs with shorter chains was easier to be absorped and stabler at the interface. These LDs fractions were used to prepare O/W emulsions, and their storage stability, droplet size, microstructure and rheological properties were measured. The mean size of the emulsions ranged from 3.93 to 5.13 μm, which was negatively correlated with the chain length of the LDs. The creaming index (CI) of the shortest LDs stabilized emulsion was the lowest after 15 days of storage, CI was 3.16%. The presence of LDs at the oil-water interface was validated by fluorescence microscope. Furthermore, the short chain LDs stabilized emulsion had better storage modulus (241.53 Pa), loss modulus (35.22 Pa) and viscosity (17.28 mPa s). These results indicated that within the DP range obtained in this study, short chain LDs had stronger emulsifying ability.