Different types of dietary fibers from citrus peels synergistically stabilize pickering emulsions

Citrus peels contain three main dietary fibers-cellulose (Cel), hemicellulose (Hem), and pectin (Pec)-which are widely used as bio-based materials but have limitations as sole emulsifiers in Pickering emulsions (PEs). In this study, Pec, Hem and Cel were extracted sequentially from citrus ( Citrus maxima ) peels and their chemical structures were characterized using Fourier transform infrared spectrometry, X-ray diffraction, and atomic force microscopy. The stabilizing effects of the three alone and in combination on PEs were compared systematically. The combination of Hem + Pec caused substantial emulsification and remained stable for 3 days without delamination, compared with individual component-stabilized emulsions. However, the Hem + Pec + Cel emulsification was weaker than that of Hem + Pec. Isothermal titration calorimetry and interfacial characterization revealed the presence of strong hydrogen bonding between Hem and Pec, which improved the wettability of the interface (contact angle 89.2°). In addition, the Hem + Pec interface had superior film thickness (160 nm), had good steric resistance, resulting in the formation of an ordered network structure in PE Hem + Pec . The droplet aggregation was effectively prevented, thus stabilizing PE Hem + Pec . These findings provide a scientific basis for the synergistic stabilizing effects of plant-derived dietary fibers on PEs, promoting the development of natural polysaccharide-based emulsifiers.