Pickering Emulsion Gels Prepared by Hydrogen-Bonded Zein/Tannic Acid Complex Colloidal Particles

Abstract

Food-grade colloidal particles and complexes, which are formed via modulation of the noncovalent interactions between macromolecules and natural small molecules, can be developed as novel functional ingredients in a safe and sustainable way. For this study was prepared a novel zein/tannic acid (TA) complex colloidal particle (ZTP) based on the hydrogen-bonding interaction between zein and TA in aqueous ethanol solution by using a simple antisolvent approach. Pickering emulsion gels with high oil volume fraction (φ(oil) > 50%) were successfully fabricated via one-step homogenization. Circular dichroism (CD) and small-angle X-ray scattering (SAXS) measurements, which were used to characterize the structure of zein/TA complexes in ethanol solution, clearly showed that TA binding generated a conformational change of zein without altering their supramolecular structure at pH 5.0 and intermediate TA concentrations. Consequently, the resultant ZTP had tuned near neutral wettability (θ(ow) ∼ 86°) and enhanced interfacial reactivity, but without significantly decreased surface charge. These allowed the ZTP to stabilize the oil droplets and further triggered cross-linking to form a continuous network among and around the oil droplets and protein particles, leading to the formation of stable Pickering emulsion gels. Layer-by-layer (LbL) interfacial architecture on the oil-water surface of the droplets was observed, which implied a possibility to fabricate hierarchical interface microstructure via modulation of the noncovalent interaction between hydrophobic protein and natural polyphenol.

The Interaction between Zein and Lecithin in Ethanol-Water Solution and Characterization of Zein–Lecithin Composite Colloidal Nanoparticles

“…This kind of α-helical spectrum was very similar to that published earlier [29]. CD ellipticity at 221 nm was widely used to estimate α-helix content in the protein structure [30]. In the presence of lecithin, the spectra of zein was changed in ellipticity at 221 nm, which indicated that the interaction between lecithin and zein significantly modulated the secondary structure of zein.…”

“…Food macromolecules and small molecular compounds are usually used to fabricate food-grade colloidal structures such as colloidal nanoparticles, complexes, and microcapsules, which show good potential for applications in food and beverage industries [1]. …”

Fabrication and characterization of novel Pickering emulsions and Pickering high internal emulsions stabilized by gliadin colloidal particles

“…Nowadays, a few works has been available on Pickering emulsions stabilized by a wide range of biological micro-and nano-particles, such as modified starch (Yusoff & Murray, 2011), cellulose nanocrystal (Kalashnikova, Bizot, Cathala, & Capron, 2011), chitin nanocrystal (Tzoumaki, Moschakis, Kiosseoglou, & Biliaderis, 2011), chitosan particles (Liu, Wang, Zou, Wei, & Tong, 2012) and flavonoids (Luo et al, 2012). Limited information is available on Pickering emulsions stabilized by protein-based particles, such as hydrophobic zein colloid particles (de Folter, van Ruijvena, & Velikov, 2012;Wang et al, 2015;Zou, Guo, Yin, Wang, & Yang, 2015), kafirin nanoparticles (Xiao, Li, & Huang, 2015), as well as hydrophilic whey protein microgel particles (Destribats et al, 2014), soy protein nanoparticle aggregates (Liu & Tang, 2013). Gliadins, one of the most abundant storage proteins in cereals, are prolamine-type proteins in wheat.…”

Zein/tannic acid complex nanoparticles‐stabilised emulsion as a novel delivery system for controlled release of curcumin

“…The ZTP‐stabilised emulsions were prepared as described in our previous study (Zou et al ., ). Zein powders (2.5 g) were dispersed in ethanol‐water solution (100 mL, ethanol:water = 7:3, v/v) and stirred overnight to allow complete hydration.…”