High moisture extrusion of wheat gluten: Relationship between process parameters, protein polymerization, and final product characteristics

Functionality of Ingredients and Additives in Plant-Based Meat Analogues

“…Gluten forms thin protein films upon simple deformation and elongation, transforming the meat analogue dough into a fibrous material [ 53 ]. This three-dimensional network is a result of disulphide protein linking [ 59 ], which causes also the formation of fibrous structures during high-moisture extrusion [ 26 , 60 , 61 ]. Disulphide bonds can be intramolecular or intermolecular, depending on the protein class.…”

Analysis of the complex rheological properties of highly concentrated proteins with a closed cavity rheometer

“…During the extrusion of foams (e.g., ready-to-eat cereals), structuring in the extruder die due to expansion is additionally influenced by the elasticity of the material [7][8][9][10]. In the case of protein extrusion to produce meat analogues, the flow characteristics in the die section are expected to have a large impact on the structuring of these materials, which again are a strong function of the rheological properties [11][12][13][14].…”

“…But reactivity remains an issue: Depending on the geometry, it might take up 30 seconds to pass the capillary device, thus leading to changes in the rheological properties along the die. Especially in highly reactive protein extrusion, polymerization was found to occur after the die section [14], i.e., in the inline rheometer between two pressure sensors, and to influence the accuracy and reliability of results.…”

Meat analogs: Protein restructuring during thermomechanical processing

“…Temperature is an essential thermomechanical stress parameter to which concentrated protein mixtures are subjected while undergoing various biomechanical reactions. These reactions influence the protein interactions and the flow behavior during the structuring process, which determines the extent of anisotropy in the structured matrix (Grabowska et al, 2016;Krintiras et al, 2015;Pietsch et al, 2019aPietsch et al, , 2019b. During TMP, the protein molecules undergo conformational changes through unfolding, alignment, collision, and aggregation via covalent and noncovalent cross-linking, which are responsible for fiber formation (Figure 1) Presence of carbohydrate in SPC (67% protein) and SPI (90%) during TMP The presence of carbohydrates improved the AI in structure formation Grabowska et al, 2016 The high-moisture extrusion trials were carried out using an SPC with the addition of 0.75%, 1.5%, 2.25%, and 3% ICGN (by dry mass) An increase in ICGN concentration led to harder, more fibrous, and less juicy products, resulting in a significantly improved overall acceptance; the extrudate with 1.5% ICGN was preferred by the panelists Palanisamy et al, 2018 TMP (shear cell) of 45% SPI-pectin blend in a shear cell sheared for 15 min at 30 rpm and 140 • C Phase separation of the dispersed phase pectin is a prerequisite for fibrous structure formation in the SPI mixture, whereas the concentration of the dispersed phase and the shearing temperature increase the length of the deformed dispersed phase droplets into long filaments, leading to higher anisotropy Dekkers et al, 2018c;Dekkers, Hamoen, et al, 2018;Dekkers, Nikiforidis, et al, 2016 ( The presence of NaCl resulted in stronger interactions between divalent Ca ions and micelles while improving the rheological property of the dispersions, facilitating fibrous structure formation Grabowska et al, 2012& Kulozik, 2015Zhang et al, 2019).…”

“…Such extreme conditions during TMP lead to polymerization because extensive disulfide cross‐linkages result in irreversible aggregation of the protein molecules (Figure 1) (Chen, Wei, et al., 2011; Langstraat et al., 2015; Liu & Hsieh, 2007, 2008; Pietsch et al., 2019a; Wang, Luo, et al., 2017). Increasing the temperature intensifies the reaction rate for protein polymerization while encouraging buried SH groups in the protein molecules to participate in covalent intramolecular disulfide linkages (Chen et al., 2010; Pietsch et al., 2018), thus imparting a higher AI and an increased hardness in the structure under the impact of high‐temperature treatment (Pietsch et al., 2017, 2019b). However, an anisotropic fibrous structure was attained in a dense 30% Ca‐caseinate dispersion using a shear cell technique at a low temperature of 50 °C but with enzyme‐assisted cross‐linking (Manski et al., 2007b; Wang et al., 2019a, 2019b).…”