Rheological and nuclear magnetic resonance characterization of porcine plasma protein-stabilized gel-like emulsion affected by pH and heating

Fabrication and Characterization of Ultra-High-Pressure (UHP)-Induced Whey Protein Isolate/κ-Carrageenan Composite Emulsion Gels for the Delivery of Curcumin

The emulsion gels have attracted extensive interests due to their unique physical characters, remarkable stability, and control release properties of flavor and functional components compared to emulsions in liquid. In the current work, whey protein isolate (WPI)/κ-carrageenan (κ-CG) composite emulsion gels were fabricated based on the ultra-high-pressure (UHP) technology, in replacement of the traditional thermal, acid, or enzyme processing. Uniform composite emulsion gels could be fabricated by UHP above 400 MPa with minimum WPI and κ-CG concentrations of 8.0 and 1.0 wt%, respectively. The formation of UHP-induced emulsion gels is mostly attributed to the hydrophobic interaction and hydrogen bonding. The emulsion gels with different textures, rheology properties, and microstructures could be fabricated through adjusting the formulations (WPI concentration, κ-CG concentration, and oil phase fraction) as well as processing under different conditions (pressure and time). Afterward, curcumin-loaded emulsion gels were fabricated and subjected to an in vitro simulated gastrointestinal digestion in order to investigate the gastrointestinal fate of curcumin. In vitro simulated digestion results demonstrated that the UHP treatment significantly retarded the release of curcumin but had little impact on the bioaccessibility of curcumin. The results in this work provide useful information for the construction of emulsion gels through a non-thermal process, which showed great potential for the delivery of heat-sensitive bioactive components.

Nano Filling Effect of Nonmeat Protein Emulsion on the Rheological Property of Myofibrillar Protein Gel

Incorporation of vegetable oils through pre-emulsification has received notable attention for delivering polyunsaturated fatty acids to emulsified-type meat products. The two important influencing factors of the rheological property of composite myofibrillar protein (MP) gel are emulsion droplet size and active or inactive interaction between interface and meat proteins. Incorporation of nonmeat protein emulsion (2% protein (w/w), egg-white protein isolate (EPI), porcine plasma protein (PPP), or sodium caseinate (SC)) with different droplet sizes (nano or macro) to a model of 2% MP gel was investigated in this research. The results of drop size measurement showed that 15,000 psi homogenizing could decrease the diameter of emulsion drop from macro- to nanoscale in the range of 324.4−734.5 nm. Active fillers (PPP and EPI emulsions) with nanodroplet size did not influence the viscosity of emulsion-filled composite cold sols but caused positive filling effects on the MP gel matrix after heating, as evidenced by the density microstructure. PPP and EPI nano-emulsion-filled composite MP had a significant high storage modulus enforcement effect, which reached nearly eight times those of other treatments (p < 0.05). Similarly, the results of thermal scanning rheology and a large-deformation mechanical test showed that PPP and EPI emulsions with nanoscale droplets, other than macroscale, had the highest gel strength of heat-induced emulsion-filled composite MP gel (p < 0.05). Overall, these findings will be helpful for selecting the correct pre-emulsified protein and designing the textural properties of foods.