Inhibition of Heat-Induced Flocculation of Myosin-Based Emulsions through Steric Repulsion by Conformational Adaptation-Enhanced Interfacial Protein with an Alkaline pH-Shifting-Driven Method

Abstract

Protein conformational rearrangement triggered by adsorption to the hydrophobic interface of oil droplets has long been considered as a key factor in emulsification. In this study, an alkaline pH-shifting-driven conformational adaptation enhanced interfacial proteins was used to improve their stability against heat-induced flocculation of myosin emulsions. We used the unfolded myosin at pH 12 to emulsify soy oil and then readjusted the pH of the emulsion to neutral. The corresponding myosin emulsion (0.5% w/v protein, 10% v/v soy oil, and 0.6 M NaCl) almost not flocculated when heated at 75 °C for 30 min. Moreover, after thermal treatment, the particle size of the emulsion was not significantly increased (P > 0.05) and the emulsion did not exhibit a creaming phenomenon after a week. Based on the circular dichroism and Fourier transform infrared analysis, we speculated the superiority of the emulsion is closely related to the alkaline pH-shifting-driven conformational adaptation enhanced interfacial protein. Additionally, the resulting steric stabilization in overcoming the attractive hydrophobic forces between denatured protein molecules coated droplets might be the main factor for the inhibition of heat-induced flocculation of the emulsion. Our research may have important implications for the formulation of protein-stabilized oil-in-water emulsions.

Effects of Tea Polyphenol Palmitate Existing in the Oil Phase on the Stability of Myofibrillar Protein O/W Emulsion

“…To ensure complete dissolution, different concentrations of TPP (0, 0.01%, 0.03%, and 0.05% (w/w)) were added to the soy oil and heated at 80 • C for 4 min [18]. O/W emulsions stabilized by MP were prepared according to the method of Li [19]. In brief, 10 g of soy oil with TPP and 90 g of MP solution were mixed with a homogenizer (Ultra Turrax T25 BASIS, IKA, Staufen im Breisgau, Germany).…”

“…The droplet surface average sizes of emulsions were measured according to our previously reported method [19] using a Malvern Mastersizer 3000 (Malvern Instruments Ltd., Malvern, Worcestershire, UK). The refractive indexes of the dispersed phase (soy oil) and dispersant medium were 1.456 and 1.33, respectively.…”

Processable Composites with Extreme Material Capacities: Toward Designer High Internal Phase Emulsions and Foams

“…Since emulsions and foams are thermodynamically unstable, they typically require an amphiphilic stabilizer, such as a traditional molecular surfactant, − particles, − and block copolymers ,, or amphiphilic (homo)­polymers. − They are summarized in Tables and . They adsorb to the interface/surface and are believed to stabilize the interface/surface through either electrostatic repulsion − or steric repulsion. − However, the exact mechanism of how they protect droplets and bubbles and what kind of properties are needed is not clear, because destabilizing processes are not static, but highly dynamic. Coalescenceone of the main destabilizing mechanisms of emulsionsis a representative dynamic process in which two droplets approach one another while the fluid in between them drains out, applying stress to the droplet interface .…”

Properties of Myofibrillar Protein in Frozen Pork Improved through pH-Shifting Treatments: The Impact of Magnetic Field

“…Pezeshk et al [6] obtained optimal modification of shrimp by-products at a pH of 12.5. Li et al [7] indicated that treatment at pH 12 significantly improved the solubility and emulsification of myosin compared to pH 9, 10, and 11. Such an increase in pH values, on the one hand, contradicts green processing principles, and on the other hand, it could facilitate the formation of covalent bonds among MPs, leading to protein aggregation [4].…”