Interfacial behavior and micro-rheological performance of Pickering emulsions co-stabilized by β-cyclodextrin and xanthan gum

Pickering emulsions have higher physical and energy barriers than typical emulsions, preventing emulsion droplets aggregation more effectively. The poor surface activity of β-cyclodextrin (CD) has limited its application in Pickering emulsions, and in order to improve the emulsifying performance of CD, in this paper, Pickering emulsions for usage in the food pathway were prepared using the xanthan gum (XG)/CD complex with different mass ratios. The CD was mixed with XG at a same concentration to form XG1/CD1 mixture, which possessed the highest absolute value of ζ-potential (54.5 mV), optimal wettability (76.9°) and interfacial behavior (like minimum interfacial tension, highest interfacial pressure, diffusion rate, penetration rate and rearrangement rate), could be firmly adsorbed at the oil-water interface and supply electrostatic repulsion and steric hindrance against the aggregation of emulsion droplets. Subsequently, the micro-rheological analysis indicated that XG1/CD1-stabilized emulsion had the highest MVI value (0.79 nm−2·s at 3600 s), suggesting it may be more dominant during long-term stability. Furthermore, the correlation between interfacial behavior of the XG/CD complex and the emulsion' long-term stability index was revealed by establishing a Pearson correlation analysis model, and the results demonstrated that the long-term stability of the Pickering emulsions can be predicted by the interfacial behavior of XG/CD complex, which had a significant correlation (p ≤ 0.05). Our findings not only present a novel application for CD and XG in food, but also a new strategy for creating food-grade Pickering emulsion.