Protein extrusion texturized

Extrusion Texturized Dairy Proteins Processing and Application... 

The higher protein content whey products are used in many products, and have been mainly promoted for their health benefits. Our contribution is creating extrusion texturized whey products that expands the range of products that can contain whey proteins (Onwulata, 2009 Onwulata et al., 2010). 

There is a continuing interest to improve and extend the fimctional properties range of dairy proteins to provide both health benefits and their characteristic physical behaviors under different temperature, moisture, and pH conditions so that they may be included in foods that ordinarily do not contain them. One such research area is the extrusion texturization of whey proteins, which have resulted in dairy proteins with new characteristics imparted by a controlled texturization process, depending on the application desired (Hale et al., 2002 Manoi and Rizvi, 2008 Onwulata, 2009 Onwulata et al., 1998). Protein texturization is a two-step process that involves, first, the unfolding of the globular structure (denaturation) and, second, the alignments of the partially unfolded structures in the direction of mass flow in the extruder. The surface characteristics are imparted at the extruder die as the molten mass exits (Onwulata et al., 2003a). 

Extrusion texturization is a process that uses mechanical shear, heat, and pressure generated in the food extruder to change the structures of food components, including proteins (Harper, 1986). Protein texturization creates filamentous structures, crumbly surfaces, or other physical formations by restructuring or realigning folded or tightly wound globular structures into stretched, layered, or cross-linked mass (Kinsella and Franzen, 1978). 

Extrusion texturization minimizes the water binding capacity of dairy protein products, in decreasing order, WPI > WPC > NDM, as temperature increases, making them interact better with starch. 

It is demonstrated here that extrusion is an effective tool for texturing whey proteins to create new functions for dairy proteins and that thermally denatured WPl is a unique ingredient that can be used in large amounts in nontraditional applications for non-TWPl. This review covers the use of extrusion texturized dairy ingredients in foods however, there are other examples of fhe successful use of this technique along with the product, TWPl in different types of nonfood applications, such as in biodegradable films, and bioplastics. 

Hale, A. B., Carpenter, C. E., and Walsh, M. K. (2002). Instrumental and consumer evaluation of beef patties extended with extrusion-textured whey proteins. /. Food Sci. 67,1267-1270. 

Onwulata, C. I. (2009). Use of extrusion-texturized whey protein isolates in puffed corn meal. J. Food Proc. Pres. 34(2010), 571-586. 

Thermoplastic extrusion technology has been used to texturize many defatted vegetable protein ingredients, and produce many fibrous structures and meat-like textures. Such processes have been used extensively to prepare meat analogs (1, which have found their widest application in formulation of foods for institutional markets (3). A primary disclosure of extrusion texturization of vegetable proteins was made by Atkinson ( ). General descriptions of various extrusion processes have also been reported (1, 5-14). ... 

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. 

Figure 3. TLMs of extrusion texturized pH-modified soy flours (I) pH 9.0 (2) pH 8.0 (3) pH 6.6 (4) pH 5.6 (5) pH 5.3 extruded at LFR (6) pH 5.3 extruded at HFR. Note that alkaline pH could increase the fihrousness of the protein matrix acidic pH produced the opposite effect. P, protein C, insoluble carbohydrate.

Figure 8. Exterior morphologies of extrusion texturized surfactant-added soy flours. Control, no surfactant added product Tolutein, yeast protein CSL SSL. Note the effect of surfactant on the diameter and surface smoothness of extrudates. (Mag. J.5X.)...

TABLE VIII. Protein Solubility and Selected Physical Properties of Extrusion Texturized Succinylated Soy Flours—... 

Figure 25. TLMs of extrusion texturized chemically modified soy flours (J) control (2)0.1% Na,SO, added (3) 0.2% Na,SO, added (4) 0.1% cysteine-HCl added (5) 0.2% cysteine-HCl added (6) 0.2% NotSO, and 1% SDS added (7) 0.01% KIO, added and (8) 0.05% KIO, added. Note that both NaiSOt and cysteine-HCl can increase the flbrousness of protein matrix but KIOs has the opposite effect. P, protein C, insoluble carbohydrate.

Stojceska et ah (2008) studied the incorporation of cauliflower trimmings into ready-to-eat expanded products (snacks) and their effect on the textural and functional properties of extrudates. It was found that addition of cauliflower significantly increased the dietary fiber and levels of proteins. Extrusion cooking significantly (P < 0.0001) increased the level of phenolic compounds and antioxidants but significantly (P < 0.001) decreased protein in vitro digestibility and fiber content in... 

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. 

Traditionally, extrusion texturization of soy protein has been used to create meat analogues. Addition of sodium hydroxide during extrusion does not aid in texturization, with worse product quality at high pH (Dahl and Villota, 1991). Precipitation within the extruder at the soy isoelectric point may be necessary for adequate texturization. Huang and colleagues (1995) at Iowa Sate University devised a process in which soy protein isolate could be extruded into textile fibers. Brittleness was offset by addition of glycerol during extrusion and by various chemical treatments post-extrusion. A similar process could be developed to produce superior meat-like fibers. 

Dahl, S.R Villota, R. Twin-screw extrusion texturization of acid and alkali denatured soy proteins. J. Food Sci. 1991,56, 1002-1007. 

Purely thermal denaturation of proteins requires much longer times collagen in moist heat below 120 °C needs 30 min to denature (Meyer et ah, 2005), wheat glutens must be subjected to 200-215 °C of dry heat for 72 min (Friedman et ah, 1987), and as mentioned above, whey proteins require at least 50 °C and 30 min for texturization without the use of extrusion processing. 

Polyacrylamide gel electrophoresis results suggest that p-LG undergoes a greater conformational loss as a fimction of extrusion temperature than a-LA, presumably due to intermolecular disulfide bond formation. Atomic force microscopy indicates that texturization results in a loss of secondary structure of aroimd 15%, total loss of globular structure at 78 °C, and conversion to a random coil at 100 °C (Qi and Onwulata, 2011). Moisture has a small effect on whey protein texturization, whereas temperature has the largest effect. Extrusion at or above 75 °C leads to a uniform densely packed polymeric product with no secondary structural elements (mostly a-helix) remaining (Qi and Onwulata, 2011). 

Our group has used twin-screw extrusion to produce many texturized whey-fortified puffed snacks. Whey protein has been blended with barley flour, com meal, rice flour, and wheat starch prior to extrusion, leading to corn puffs with a protein content of 20% instead of the usual 2% (Onwulata et al., 2001a). 

Extrusion is an effective means of denaturing whey proteins to create texturized products. TWP may be used as an ingredient to improve the characteristics of many foods. The production of snack foods wifh... 

Texturized or denatured WPl retained its native protein value, functionality, and digestibility when extruded below 50 °C changes in functionality occur at 65 °C and above. Through careful selection of extrusion conditions of temperature and moisture, TWPs with unique functionality can be produced. The degree of texturization increased with increasing temperature, but temperatures higher than 100 °C may be needed to form fibrous structures with WPl. 

Cheftel, J. C., Kitagawa, M., and Queguiner, C. (1992). New protein texturization processes by extrusion cooking at high moisture levels. Food Rev. Int. 8, 235-275. 

Holay, S. H. and Harper, J. M. (1982). Influence of the extrusion shear environment on plant protein texturization. J. Food Sci. 47,1869-1874. 

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