Protein texturized

Texturization is not measured directly but is inferred from the degree of denaturation or decrease of solubility of proteins. The quantities are determined by the difference in rates of moisture uptake between the native protein and the texturized protein (Kilara, 1984), or by a dyebinding assay (Bradford, 1976). Protein denaturation may be measured by determining changes in heat capacity, but it is more practical to measure the amount of insoluble fractions and differences in solubility after physical treatment (Kilara, 1984). The different rates of water absorption are presumed to relate to the degree of texturization as texturized proteins absorb water at different rates. The insolubility test for denaturation is therefore sometimes used as substitute for direct measurement of texturization. Protein solubility is affected by surface hydrophobicity, which is directly related to the extent of protein-protein interactions, an intrinsic property of the denatured state of the proteins (Damodaran, 1989 Vojdani, 1996). 

Spatial spectral analyses of TWPI look quite different from the non-texturized proteins at the ultrastructural level (Fig. 5.5A). TWPI extruded at 100 °C had densely packed structures with spacing of 2-6 nm... 

Kinsella, J. E. and Eranzen, K. L. (1978). Texturized proteins Fabrication, flavoring, and nutrition. Crit. Rev. Food Sci. Nutr. 10,147-207. 

Textured Soy Proteins. Textured vegetable proteins, primarily textured flours and concentrates (50% protein and 70% protein, dry basis, respectfully) are widely used in the processed meat industry to provide meat-like structure and reduce ingredient costs (3-6, 9-10). Available in a variety of sizes, shapes, colored or uncolored, flavored or unflavored, fortified or unfortified, textured soy proteins can resemble any basic meat ingredient. Beef, pork, seafood and poultry applications are possible 03, 4-7, 15, 19) Proper protein selection and hydration is critical to achieving superior finished product quality. Textured proteins have virtually no solubility and, thus, no ability to penetrate into whole muscle tissue Therefore, textured soy proteins are inherently restricted to coarse ground (e.g. sausage) or fine emulsion (e.g. weiners and bologna) products, and comminuted and reformed (i.e. restructured) meat products. None are used in whole muscle absorption or injection applications (2-4, 6, 11). 

Kinsella (16), in his recent review on texturized proteins, described the texturization process as follows the globular proteins (glycinins) in the aleurone granules become hydrated within the extruder barrel, are gradually unravelled, and are stretched by the shearing action of the rotating screw flites. 

The profound reason for having this many unknowns is attributed to the fact that the "technology" of extrusion texturization is well in advance of the "science". In-depth knowledge in the "science" portion of extrusion texturization will provide principles which can be used to accurately define the texturized protein product. This basic scientific knowledge should also provide data which could be used to improve operating efficiency of extruders, and serve as a basis for producing texturized protein foods, with desired characteristics for specific product applications, from a wide variety of raw ingredients. 

EXTENDER. A low-graxily material used in paint, ink. plastic, and rubber formulations chiefly to reduce cost per unit volume by increasing bulk, Extenders include dialomaccou.s earth, wood flock, mineral rubber, liquid asphalt, etc. Microscopic droplets of water fixed permanently in a plastic matrix are an efficient extender tor polyester resins. In the food industry, the term refers to certain extruded proteins, especially those derived from soybeans, which are used in meat products to provide equivalent nutrient values at lower cost. Made from defatted soy flour, they are often called textured proteins. 

An example where extension and orientation of protein molecules is used to bring them together for interaction is in artificial meat products, including textured protein products. In such products, disulfide bonds, hydrophobic bonds and hydrogen bonds are formed among the proteins extended as fibers as shown in Figure 12(2e). 

The development of physical methods for texturizing proteins has significantly amplified their use in several conventional and simulated foods. The principal techniques of physical modification which have been thoroughly reviewed are thermoplastic extrusion, fiber spinning and steam texturization (3,4,5). 

Industrial applications of proteins include plastics, adhesives, and fibers derived from casein and soybean protein, but these have been declining in recent years. Special forms in which proteins are commercially available include textured proteins for food products, and protein hydrolyzate and liquid predigested protein, both for medical use. See ribonu-... 

Effects of Alkali. Although alkali had been used to treat certain foods for many years, only recently has it been used widely by the texturized protein industry. Alkali-mediated degradation of proteins has long been known (13, 39-44). Some of the main initial reactions are apparently / -eliminations of cystines and substituted serines and threonines. The products (or their intermediates) then alkylate various other amino acid side chains to form substances like lanthionine and lysino-alanine [N -(DL-2-amino-2-carboxyethyl)-L-lysine]. Possible toxicities are currently under investigation (45, 46), but nutritional losses could also be important. 

Texturized protein foods have become very important in commercial food products (50). Some of the methods used involve chemical changes perhaps only indirectly (such as alkali-produced cross-linkages). Here is a probable place for advances in food technology in the application of chemical cross-linking agents under controlled conditions. This would include the bifunctional reagents. 

Soy flours and grits—full-fat and defatted Soy protein concentrates Soy protein isolates Textured protein products... 

Yuba has very chewy texture and is one of the first texturized protein foods (Fig. 14.4). On average, yuba contains 55% protein, 26% neutral lipids, 2% phospholipids, 12% carbohydrate, 2% ash, and 9% moisture (Wu Bate, 1972). Among several Oriental soyfoods, soy protein in yuba has the highest percentage of digestibility, -100% (Ikeda et al., 1995). Due to limited production and high cost, yuba is considered as a delicacy. 

Hill, D. Fiber, texturized protein and extrusion. Petfood Technology J.L. Kvamme, T.D. Phillips, Eds. Watt Publishing Go. Mt. Morris, 2003. 

The meat-like appearance in spun protein isolates results from strands of parallel fibers, but in extruded SFs, SPCs, and SPI, the meat-like structure is created from multi-laminate palisade layers. Extruder-texturized proteins are readily acceptable to... 

Another example is characterization of a protein and how it is affected by water content [34], Samples of a soy protein were isolated with water contents varying between 15% and 40%. To produce textured protein, it is necessary to cook the protein at an elevated temperature and allow it to rehydrate after cooking. The temperature needed for texturization is that of the denaturation of the protein. The DSC scans in Figure 20 show the denaturation temperatures as a function of initial water content and provide processing and quality control options. 

For foodstuffs extruders used for pasta and cereals food cooker-extruder used for soup bases, puffed products, dry cereals, textured proteins and pet foods. 

Uses High protein foods, esp. textured proteins and meat analogs antioxidant, emulsifier extending shelf life in foods animal feeds tablet disintegrant... 

Lawrie and Ledward (1988) reviewed the use of thermoplastic extrusion in the production of animal-derived ingredients. This technique has been applied successfully to the production of textured proteins, which retain much of their protein functionality. Material is forced through a hollow barrel by a tapered screw, which causes high shearing, and an increase in temperature and pressure. The final product is textured as a result of fibre rearrangements, and realignments in the barrel. 

Extrusion has found wide application in the production of snack foods and breakfast cereals from maize, as well as producing textured soya proteins. Extrusion technology should be investigated as a means of preparing novel textured proteins from animal sources. 

FIG. 5 Preparation of protein hydrolysate. Protein powder can be blended directly with water, while textured protein samples need to be homogenized before the adjustment of pH. 

A decrease in tbe inhibitor activity can also be achieved by soaking. A tbermal step can then follow under gentler conditions. Altbougb the processing of soybeans into protein isolates, textured protein, or meat surrogates causes a decrease in the inhibitor activity against tr)fpsin, noticeable activity can still be present (Table 16.18). Soybeans promote the growth of rats to the same extent as casein when about 90% of tbe inhibitor activity is eliminated (Table 16.19). 

On the basis of their manifold functionalities, proteins can be used both in various nutritional and technical applications texturized proteins as meat extenders and replacers as well as fibres for textiles, protein-stabilized emulsions and foams in food dressings as well as asphalt emulsions or fire control foams, protein-based films, and coatings for fruit moisture control as well as for packaging purposes. 

The trend toward quick-service convenience foods requiring fabrication, dehydration, rehydration, etc., brought the versatility of textured proteins to the forefront in the mid and late 1960s. Likewise, the economic performance of soy protein in chopped emulsified meats, egg white replacement in cakes, and the substitution of nonfat dry milk in baked goods all point to a lower cost per unit of performance, while at the same time maintaining the required level of consumer acceptance. 

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