Fabrication of gel-like emulsions with γ-zein particles using microfluidization: Structure formation and rheological properties

In this work, gamma-zein, which is a type of cysteine rich prolamine in corn, was prepared into particles for fabricating stable gel-like emulsions. The effects of homogenization pressure (0.1-120 MPa) on structure formation and rheological properties of emulsions were systematically studied. Microscopy showed that gamma-zein particles provided stabilization at droplet interfaces, and that excess protein particles provided a particle network in continuous phase, and microfluidization significantly decreased droplet size and induced to form droplet clusters and gel-like network. With an increase of homogenization pressure, protein content adsorbed at droplet interfaces and entrapped within gel-like structure of emulsions increased, and more hydrophobic interactions and disulfide bonds between protein particles were formed. As a result, stronger gel strength of emulsions were observed, for example, apparent viscosity, storage modulus (G'), loss modulus (G ), and G'/ G crossover strain (gamma co) increased, the frequency dependency of G' (n, G' con) decreased. Also, Lissajous curves were used to further understand the non-linear viscoelastic behavior of these emulsions. Emulsions prepared without microfluidization (control, 0.1 MPa) showed a weak gel structure with viscous-dominating behavior at high strain, while emulsions prepared with microfluidization showed predominantly elastic behavior at low strain, and plastic-dominating behavior at high strain. These findings showed that cysteine rich protein based-emulsion gels with tunable microstructure and rheological properties can be easily produced by controlling the homogenization pressure.

Automated summary

In this study, stable gel-like emulsions were prepared using gamma-zein particles, and the effects of homogenization pressure on the structure and rheological properties of the emulsions were investigated. The results showed that increasing the homogenization pressure resulted in stronger gel-like structures and changed the rheological properties of the emulsions. Additionally, emulsions prepared with microfluidization exhibited different rheological behaviors.