Effects of extrusion conditions on the physicochemical properties of soy protein/gluten composite

Abstract

Soybean protein-gluten blend was extruded using a co-rotating twin-screw extruder. Effects of different extrusion conditions on the textural properties of extrudates were analyzed by central composite design through the evaluation of texturization index, water holding capacity, and hardness of extruded protein products. Extrusion process variables including feed moisture content (40%-60%), screw speed (12-20 Hz), extrusion temperature (120°C-180°C), and gluten content (16%-32%) were studied by the nonlinear regression equations analysis. The extrusion process was also optimized using response surface methodology (RSM). The influence of moisture content on the hardness of extrudate was the most significant. The optimized results, including feed moisture content, extrusion temperature, screw speed and gluten content were 49.18%-50.15%, 155.24°C-159.86°C, 16.41-16.73 Hz, 20.00%-20.03%, respectively. The microstructures of TISP products were analyzed by scanning electron microscopy (SEM) and the changes of protein molecules before and after extrusion were also analyzed by SDS-PAGE electrophoresis.

Physical and Microstructure Properties of Oyster Mushroom-Soy Protein Meat Analog via Single-Screw Extrusion

“…The TI was dependent on the extruder parameters (e.g., type of extruder, screw configuration, rotation speed, barrel temperatures, and feed rate) and feed conditions (e.g., ingredients and moisture content) applied. Numerous studies have investigated the effect of these independent variables on the TI of soy protein-based meat analogs [ 10 , 22 , 23 , 30 , 31 , 32 ]. The TI of the oyster mushroom-soy protein meat analogs ranged from 0.77 to 1.19 ( Table 3 ).…”

“…The TI of the extrudate achieved the same range of TI (0.7–1.2) as presented by Chen et al and Fang et al on meat analogs made from soy protein without additional ingredients, which were produced by a twin-screw extruder [ 23 , 31 ]. However, several studies have reported a higher range of TI (1.3–1.7) in soy protein-based meat analogs added with wheat gluten and extruded via twin-screw extrusion [ 22 , 30 ]. Figure 3 illustrates the TI of extrudates containing 0%, 7.5%, and 15% oyster mushroom as compared with the TI of hydrated TVP and chicken meat (breast and drumstick).…”

“…The TI was determined following the procedure reported by Wu et al [ 22 ], with some modifications in the test setting parameters of TA.XT Plus Texture Analyzer (Stable Micro Systems, Surrey, UK). For sample preparation, the samples (e.g., extrudate, hydrated textured vegetable protein (TVP), and chicken meat) were cut into squares (2 × 2 cm).…”

“…They were cooked in water at 100 °C for 30 min and left to cool down at a surrounding temperature of 28 °C ± 1 °C for 30 min. Each sample was sheared using a Warner–Bratzler stainless steel shear probe (shear angle 60°, probe thickness: 1.00 mm) to 100% of its original thickness at a speed of along the vertical (lengthwise strength, and parallel directions (crosswise strength, to the direction of extrudate outflow from the extruder [ 22 , 23 ]. The ratio of lengthwise strength and crosswise strength expressed the TI (Equation (4)).…”

Life cycle assessment of burger patties produced with extruded meat substitutes

“…104 Currently, soybean protein concentrates and isolates are the benchmark raw materials to 105 produce extruded meat substitutes. Substantial research is performed on soymeal as a raw 106 material (Lin et al, 2002;Wu et al, 2018). Today, three countries account for over 80% of the 107 total soybean cultivation (Karuga, 2018) The configuration at the end of the extruder barrel also affects the properties of the resulting 162 163 design (FKD-2100, DIL e.V., Quakenbrück, Germany).…”