Physical properties and chemical forces of extruded corn starch fortified with soy protein isolate

Influence of legume-derived proteins with varying solubility on the direct expansion of corn starch during twin-screw extrusion processing

This study analyzed the effect of the inclusion of legume-derived proteins, specifically pea and fava bean protein, with varying solubility levels on the expansion of corn starch. Three different proteins exhibiting low, medium, or high solubility were mixed with corn starch to obtain blends containing 15%, 25%, and 35% (w/w) of the protein. Extrusion was performed on a twin-screw extruder at three different screw speeds (200, 400, and 600 rpm), a moisture content of 16% (w.b.), and a die temperature of 140°C. Obtained extrudates were analyzed for their expansion, unit density, and hydration properties, namely, water solubility index (WSI) and water absorption index (WAI). Extrudates containing the protein with the highest solubility showed different patterns than those that had proteins with low or medium solubility. Expansion ratio (ER) increased from a maximum of 3.55 ± 0.24 for pure corn starch up to 5.45 ± 0.43 when incorporating 35% of the protein with medium solubility but significantly decreased down to 1.24 ± 0.08 when incorporating 35% of the most soluble protein. The influence on the system parameters, as well as on the hydration properties, was also greatest for the blends containing the protein with the highest solubility. Even though significant Pearson correlations were observed between protein solubility and ER (r = -0.579), unity density (r = 0.614), WSI (r = -0.634), torque (r = -0.612), as well as specific mechanical energy (r = -0.451), further research is needed to evaluate if the solubility is indeed the reason for certain behaviors or if other protein characteristics are more critical for expansion. PRACTICAL APPLICATION: This manuscript provides practical information on the influence of the addition of legume-derived proteins with different solubility levels on direct expansion. The obtained results may help the industry with the selection of the appropriate proteins for inclusion levels in producing high protein direct-expanded extruded food products.

Recent Advances in the Processing and Manufacturing of Plant-Based Meat

Plant protein technology is a core area of biotechnology to ease the problem of human protein demand. Plant-based meat based on plant protein technology is a growing concern by global consumers in alleviating environmental pollution, cutting down resources consumption, and improving animal welfare. Plant-based meat simulates the texture, taste, and appearance of animal meat by using protein, lipid, carbohydrate, and other plant nutrients as the main substances. This review summarizes the main components of plant-based meat, processing technology, standard formula, market competition, and formula and texture of future research directions. According to the existing methods of plant-based meat fiber forming, the development process and characteristics of four production processes and equipment of plant-based meat spinning, extrusion, shearing, and 3D printing are emphatically expounded. The processing principles and methods of different processing technologies in plant-based meat production are summarized. The production process and equipment of plant-based meat will pay more attention to the joint production of various processes to improve the defects of plant-based meat production process.

Food extrusion: An advanced process for innovation and novel product development

Extrusion is a versatile process capable of producing a variety of new and novel foods and ingredients, thus increasing manufacturing opportunities. Further, it could provide nutritious, safe, sustainable, and affordable foods, especially directed at individualized consumer needs. In addition to past research efforts, more investigations should be conducted in order to refine, redesign, or develop new extrusion processing technologies. The present review highlights the current advances made in new and novel food product development by considering the extrusion process, the influencing parameters, and product characteristics and properties; the most promising extrusion processes that can be used in novel food product and ingredient development, such as extrusion cooking, hot-melt extrusion, reactive extrusion, and extrusion-based 3D printing; the possibilities of using various raw materials in relation to process and product development; and the needs for product development modeling along with extrusion process design and modeling. In correlation with extruded product development, topics that merit further investigation may include structure formation, plant and animal biopolymers functionalization, biopolymer reactions, process simulation, modeling and control, engineering and mechanical aspects of extruders, analysis of pre-processing treatments, as well as prototyping, risk analysis, safety, sensory and consumer acceptance.

High moisture extrusion cooking of meat analogs: A review of mechanisms of protein texturization

High-moisture extrusion cooking (HMEC) is an efficient method for converting proteins and polysaccharides into fibrous structure that is used in the industrial production of meat analogs. The purpose of this review is to systematically evaluate current knowledge regarding the modification of protein structure including denaturation and reassembly upon extrusion processing and to correlate this understanding to the structure of the final products. Although there is no consensus on the relative importance of a certain type of bond on extrudates' structure, literature suggests that, regardless of moisture level, these linkages and interactions give rise to distinctive hierarchical order. Both noncovalent and disulfide bonds contribute to the extrudates' fibrous structure. At high water levels, hydrogen and disulfide bonds play a dominant role in extrudates' texture. The process parameters including cooking temperature, screw speed, and moisture content have significant albeit different levels of impact on the texturization process. Their correlation with the ingredients' physiochemical properties provides a greater insight into the process-structure-function relationship of meat analogs. The tendency of protein and polysaccharide blends to phase separate rather than produce a homogeneous mix is a particularly important aspect that leads to the formation of fibrous layers when extruded. This review shows that systematic studies are required to measure and explain synergistic and competitive interactions between proteins and other ingredients such as carbohydrates with a focus on their incompatibility. The wide range of plant protein source can be utilized in the HMEC process to produce texturized products, including meat analogs.

Extrusion Processing of Rapeseed Press Cake-Starch Blends: Effect of Starch Type and Treatment Temperature on Protein, Fiber and Starch Solubility

For the valorization of oilseed press cakes into food products, extrusion can be used. A common way of applying the protein- and fiber-rich press cakes in directly expanded products is the combination thereof with starch, since starch gives a favourable texture, which correlates directly to expansion. To control product properties like expansion of protein and fiber-rich extruded products, the underlying physicochemical changes of proteins, fibers and starch due to thermomechanical input need to be comprehensively described. In this study, rapeseed press cake (RPC) was extruded and treated under defined thermomechanical conditions in a closed-cavity rheometer, pure and in combination with four starches. The impact of starch type (potato PS, waxy potato WPS, maize MS, high-amylose maize HAMS) and temperature (20/25, 80, 100, 120, 140 °C) on protein solubility, starch gelatinization (D_gel), starch hydrolysis (S_H) and fiber solubility of the blends was evaluated. The extrusion process conditions were significantly affected by the starch type. In the extruded blends, the starch type had a significant impact on the protein solubility which decreased with increasing barrel temperature. Increasing barrel temperatures significantly increased the amount of soluble fiber fractions in the blends. At defined thermomechanical conditions, the starch type showed no significant impact on the protein solubility of the blends. Therefore, the observed effects of starch type on the protein solubility of extruded blends could be attributed to the indistinct process conditions due to differences in the rheological properties of the starches rather than to molecular interactions of the starches with the rapeseed proteins in the blends.

Linking Expansion Behaviour of Extruded Potato Starch/Rapeseed Press Cake Blends to Rheological and Technofunctional Properties

In order to valorise food by-products into healthy and sustainable products, extrusion technology can be used. Thereby, a high expansion rate is often a targeted product property. Rapeseed press cake (RPC) is a protein- and fibre-rich side product of oil pressing. Although there is detailed knowledge about the expansion mechanism of starch, only a few studies describe the influence of press cake addition on the expansion and the physical quality of the extruded products. This study assessed the effect of RPC inclusion on the physical and technofunctional properties of starch-containing directly expanded products. The effect of starch type (native and waxy), RPC level (10, 40, 70 g/100 g), extrusion moisture content (24, 29 g/100 g) and barrel temperature (20-140 °C) on expansion, hardness, water absorption, and solubility of the extrudates and extruder response was evaluated. At temperatures above 120 °C, 70 g/100 g of RPC increased the sectional and volumetric expansion of extrudates, irrespective of starch type. Since expansion correlates with the rheological properties of the melt, RPC and RPC/starch blends were investigated pre- and postextrusion in a closed cavity rheometer at extrusion-like conditions. It was shown that with increasing RPC level the complex viscosity |ƞ*| of extruded starch/RPC blends increased, which could be linked to expansion behaviour.

Application of extrusion technology in plant food processing byproducts: An overview

The food processing industry generates an immense amount of waste, which leads to major concerns for its environmental impact. However, most of these wastes, such as plant-derived byproducts, are still nutritionally adequate for use in food manufacturing. Extrusion is one of the most versatile and commercially successful processing technologies, with its widespread applications in the production of pasta, snacks, crackers, and meat analogues. It allows a high degree of user control over the processing parameters that significantly alters the quality of final products. This review features the past research on manufacture of extruded foods with integration of various plant food processing byproducts. The impact of extrusion parameters and adding various byproducts on the nutritional, physicochemical, sensory, and microbiological properties of food products are comprehensively discussed. This paper also provides fundamental knowledge and practical techniques for food manufacturers and researchers on the extrusion processing of plant food byproducts, which may increase economical return to the industry and reduce the environmental impact.