Ovalbumin-carboxymethylcellulose complex coacervates stabilized high internal phase emulsions: Comparison of the effects of pH and polysaccharide charge density

Encapsulation of cinnamaldehyde: an insight on delivery systems and food applications

Cinnamaldehyde is an essential oil extracted from the leaves, bark, roots and flowers of cinnamon plants (genus Cinnamomum). Cinnamaldehyde has shown biological functions such as antioxidants, antimicrobials, anti-diabetic, anti-obesity and anti-cancer. However, poor solubility in water as well as molecular sensitivity to oxygen, light, and high temperature limit the direct application of cinnamaldehyde. Researchers are using different encapsulation techniques to maximize the potential biological functions of cinnamaldehyde. Different delivery systems such as liposomes, emulsions, biopolymer nanoparticles, complex coacervation, molecular inclusion, and spray drying have been developed for this purpose. The particle size and morphology, composition and physicochemical properties influence the performance of each delivery system. Consequently, the individual delivery system has its advantages and limitations for specific applications. Given the essential role of cinnamaldehyde in functional food and food preservation, appropriate approaches should be applied in the encapsulation and application of encapsulated cinnamaldehyde. This review systematically analyzes available encapsulation techniques for cinnamaldehyde in terms of their design, properties, advantages and limitations, and food application status. The information provided in this manuscript will assist in the development and widespread use of cinnamaldehyde-loaded particles in the food and beverage industries.

Preparation and characterization of octenyl succinic anhydride modified waxy maize starch hydrolyzate/chitosan complexes with enhanced interfacial properties

The preparation and characterization of colloidal complexes based on octenyl succinic anhydride starch hydrolyzate (OSAS) and chitosan (CS) were conducted. Results showed that OSA-S/CS ratio (r) and pH significantly affected complex turbidities and yields. The highest turbidity and yield were obtained at r = 6:1 when pH was fixed, and at pH 6.5 when r was fixed. All complexes remained liquid-like except that formed at pH 6.5, which exhibited a gel structure due to the strongest complexation. OSA-S/CS complexes had intertwined core-shell microstructure and exhibited electrostatic interactions between COO^- and NH₃⁺ groups of OSA-S and CS, respectively. The complexes prepared at r = 6:1 and pH 6.0 exhibited the most suitable wettability (θ_ow = 91.97°) and interfacial adsorption dynamics. The compact lamellar network and intact cores of these complexes were also shown. This work provides profound and comprehensive information about the formation and physicochemical properties of OSA-S/CS complexes.

The microstructure and physiochemical stability of Pickering emulsions stabilized by chitosan particles coating with sodium alginate: Influence of the ratio between chitosan and sodium alginate

The purpose of this study was to further improve the physiochemical stability of the chitosan (CS) particle-stabilized Pickering emulsion by coating with sodium alginate (SA). The effect of different mass ratios of CS and SA (1:0.5-1:2) on the microstructure, rheology and the stability of the emulsions were comprehensively evaluated by various methods such as optical microscope, scanning electron microscope, rheometer, and low-field nuclear magnetism. The multilayer emulsion with low content of SA (CS:SA = 1:0.5) presented bridging flocculation. If SA concentration was high (CS:SA = 1:1-1:2), the surface of the Pickering emulsion droplets was completely covered by the SA. At this time, multilayer emulsion droplets became stable due to strong electrostatic and/or steric repulsion. Too high SA concentration (CS:GA = 1:2) might also promote the accumulation of moisture. In addition, the CS/SA multilayer emulsion showed higher coalescence stability under different environmental treatments but its creaming stability and flocculation stability were still sensitive to pH (2, 4 and 10), temperature (4 °C and 80 °C) and ionic strength (300-500 mM). In all, the addition of the proper level SA (CS:GA = 1:1-1:2) could increase the stability of CS particle-stabilized Pickering emulsion.

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

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.

Designable Carboxymethylpachymaran/Metal Ion Architecture on Sunflower Sporopollenin Exine Capsules as Delivery Vehicles for Bioactive Macromolecules

There are multiple obstacles in the gastrointestinal tract (GIT) for oral administration of bioactive macromolecules. Here, we engineered an oral delivery vehicle (sporopollenin exine capsules with carboxymethylpachymaran (CMP)/metal ion modification) with targeted release based on food-grade ingredients and processing operations. Then, the interaction and binding mechanisms between CMP and metal ions in the vehicle were investigated. By using β-galactosidase (β-Gal) as a model protein, the systems were characterized for the surface morphology and monitored by the in vitro release profile of β-Gal. Notably, the CMP/metal ion systems not only markedly decreased the CMP dosage but also achieved a valid long-term release compared with the previously reported CMP system. Among all the systems, the CMP/3% AlCl₃ system showed the best ability to control the release with the maximum residual activity of β-Gal at nearly 72% after 24 h of treatment. Subsequently, the interaction mechanism between CMP and metal ions within the system was characterized by the perspectives of microstructure, rheological properties, and spectroscopy characteristics. The results indicated that the low pH conditions are conducive to the further cross-linking of CMP and metal ions, resulting in a high gel strength and thus a dense structure, which can impact the controlled release of β-Gal in the GIT. Overall, the system may be utilized in the administration of medical and functional foods, specifically for the delivery of bioactive proteins via the oral route.