Oil‐in‐water Pickering emulsion stabilization with oppositely charged polysaccharide particles: chitin nanocrystals/fucoidan complexes

Abstract

BACKGROUND Chitin nanocrystals (ChN) are insoluble particles that can be used as stabilizers for Pickering emulsions. Their unique cationic properties and antibacterial activity have generated considerable interest among researchers. However, ChN have remained largely underexplored. Furthermore, the droplets of the emulsions stabilized by ChN are as large as 10–100 μm, and their physical stability requires further improvement. Some studies have shown that the spontaneous reaction of oppositely charged particles can effectively stabilize the emulsions. Positively charged ChN and negatively charged fucoidan (F) were therefore compounded to stabilize Pickering emulsions, and the stability of these emulsions was analyzed qualitatively. RESULTS The results showed that the composite particles comprising two polysaccharides in a mass ratio of 1:1 and at a pH of 2 (ChN1‐F1‐pH 2) possessed the lowest sulfate content (20.1%) and almost zero potential (−3 mV), indicating a high degree of neutralization of the positively charged amino group in ChN and the negatively charged sulfate group in F. Meanwhile, ChN1‐F1‐pH 2 displayed a dense network structure that improved the dispersibility and wettability (contact angle = 9.3°). Fourier transform infrared spectroscopy results confirmed that ChN and F were effectively combined through electrostatic interaction or neutralization to produce a polyelectrolyte complex. Furthermore, the particle size of the Pickering emulsion stabilized by ChN‐F was significantly reduced, and the maximum size did not exceed 10 μm; the physical and storage stability also improved. The ChN1‐F1‐pH 2 emulsion presented excellent storage stability; in particular, the emulsions stabilized by ChN1‐F1‐pH 5 and ChN1‐F1‐pH 6 exhibited excellent flocculation stabilities. CONCLUSION The size of the emulsion droplets stabilized by the oppositely charged polysaccharide particles (ChN‐F complexes) reduced significantly. Furthermore, by changing the mass ratio and pH, the microstructure and binding degree of the complexes can be adjusted, thereby promoting their adsorption on the oil–water interface and improving the stability of the Pickering emulsion. © 2020 Society of Chemical Industry

Nanochitin: Chemistry, Structure, Assembly, and Applications

“…In addition to Pickering emulsions that are solely stabilized by nanochitin, nanochitin-based composite stabilizers have been explored for the formation of multiphase materials. 422,486 This is because the cationic nature of nanochitin facilitates modification using the more typical anionic nanoparticles derived from renewable resources. 487 For instance, the stabilization ability of nanochitin was enhanced with the addition of CNF.…”

Application of Advanced Emulsion Technology in the Food Industry: A Review and Critical Evaluation

“…In particular, cellulose nanocrystals and nanofibrils have received considerable interest due to their amphiphilic nature, high aspect ratio, large elastic modulus, and ease of modification [114,133]. In addition, chitin nanocrystals [134][135][136], chitin nanofibers [137], and chitosan-tripolyphosphate (TPP) nanoparticles [138] have also been shown to act as Pickering particles.…”

Oppositely Charged Pickering Emulsion Co-Stabilized by Chitin Nanoparticles and Fucoidan: Influence of Environmental Stresses on Stability and Antioxidant Activity

“…The mean particle size and ζ-potential of the Pickering emulsion after preparation was shown in previous research [21]. Figure 1 shows the changes in the mean particle size and ζ-potential of the Pickering emulsion under different environment stresses.…”

“…To overcome the limitations of conventional emulsions, we previously fabricated a Pickering emulsion from positively charged ChNs and negatively charged fucoidan [21]. We verified that the as-synthesized Pickering emulsion comprising oppositely charged particles possessed excellent physical and storage stabilities.…”

“…ChNs were prepared according to our previously reported method Liu et al (2021) [21]. The ChN-Fuc complex was prepared by mixing 1% (w/v) ChNs and 1% (w/v) Fuc at pH 2 and then freeze-drying for further use.…”