Enhanced stability of emulsions made with super‐critical carbon dioxide extruded whey protein concentrate

Abstract

Supercritical fluid extrusion (SCFX) with carbon dioxide was used to enhance the functionality of whey protein concentrate containing 80% protein by weight (WPC80) at two (3.0 and 5.4) pH values. Different levels of oil (20, 40, 60, and 80% by weight) and functionalized whey protein (f‐WPC80; 1, 2, and 4% by weight) were used to make emulsions and quantify their characteristics such as emulsion activity index, creaming index, droplet size, and viscosity. Unextruded whey protein (c‐WPC80) and commercial sodium caseinate (NaCas) were used as controls. Results showed that gel‐like emulsions with uniform droplet size distributions were formed by f‐WPC80 (4% by weight) with 80% (by weight) oil which was stable over 3 months of storage at room temperature. Compared to emulsions formed by control c‐WPC80, the f‐WPC80 emulsions exhibited higher viscosity and shear thinning behavior. The minimum protein required for stable emulsion formation (with 80% oil) was found to be 2% by weight for f‐WPC80 and NaCas and 4% by weight in the case of c‐WPC80. The functionalized whey protein provided a better emulsion at low concentrations with good stability at room temperature and may be used as a replacement of sodium caseinate to make nutritionally superior products. Practical applications Present study showed that functionalized Whey protein concentrate (80% protein) f‐WPC80 was produced by the process of Supercritical carbon dioxide assisted extrusion which changed the structure of native protein. Two functionalized products (with pH 3.0 and 5.4) were obtained in this way. These functionalized proteins formed better oil‐in‐water emulsions which were stable against creaming and sedimentation as compared to emulsions stabilized by native WPC80 and sodium caseinate at very small concentration of protein used. Therefore it is concluded that f‐WPC80 can cover a range of food emulsions where different pH values are required. Lesser amount of stabilizer will be used commercially for emulsions. These functionalized WPC80 products may be used as a replacement of sodium caseinate to make nutritionally superior products with pH 3.0 and 5.4.

Development of curcumin‐loaded nanoemulsion stabilized with texturized whey protein concentrate: Characterization, stability and in vitro digestibility

“…This could increase the exposure of hydrophobic groups, resulting in increased emulsifying activity (Mozafarpour et al, 2019). Our results were in accordance with Javad et al (2019) who reported that EAI values of EWPC at pH 3 and 5.4 were higher than NWPC. Moreover, higher EAI was found for samples extruded at pH 3 than pH 5.4.…”

“…In addition, high protein levels reduce oil droplet coalescence since higher amounts of proteins adsorb at the interface, which would be sufficient to cover oil droplets (Javad et al, 2019;Ma et al, 2017;Manoi & Rizvi, 2009;McClements, 2004). In accordance with our results, Javad et al (2019) reported that the creaming index of EWPC was decreased.…”

“…Therefore, the adsorption velocities of proteins at the interface, the flexibility of their structure, and their ability to conform to conformational changes have a remarkable impact on their emulsification performance (Dybowska, 2011;Javad et al, 2019).…”

Comparison of emulsifying properties and emulsion stabilising properties of pea protein isolate with various modification methods

“…The increase of continuous phase viscosity also restricted the movement of oil droplets and increased the emulsion's viscosity, which was consistent with the trend reported by Javad et al . (2019). Also, phosphorylation treatment caused molecular changes due to the attachment of phosphate groups to protein molecules, changing the protein molecules and surface charges, thereby affecting the hydration layer and increasing the emulsion viscosity, which is consistent with the results of Huang et al .…”

Emulsifying properties of milk protein concentrate functionalized by supercritical fluid extrusion

“…Supercritical CO 2 extrusion is an effective technique to impart conformational changes in milk proteins and provides several advantages over steam extrusion cooking such as low-temperature (<100°C) processing, thus minimizing damage to heat-labile components, formation of uniform and porous product, and pH control. Supercritical CO 2 extrusion improves protein functionality such as gelling and emulsifying properties (Javad, Gopirajah, & Rizvi, 2019). Manoi and Rizvi (2009) successfully functionalized whey protein concentrate using supercritical CO 2 extrusion with acid addition producing a cold setting, gel-like emulsions.…”