Texturization protein contents

Oilseed proteins are used as food ingredients at concentrations of 1—2% to nearly 100%. At low concentrations, the proteins are added primarily for their functional properties, eg, emulsification, fat absorption, water absorption, texture, dough formation, adhesion, cohesion, elasticity, film formation, and aeration (86) (see Food processing). Because of high protein contents, textured flours and concentrates are used as the principal ingredients of some meat substitutes. 

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). 

The range of whey products that are used include, for example, ultra-filtered and dried WPC, which contains between 20% and 89% protein ion exchange and membrane filtered WPI, which contains at least 90-95% protein (Tunick, 2008) and other whey fraction-enriched products such as p-lactalbumin. These enriched protein whey products can be texturized and used in the manufacture of high-protein content puffed com products (Onwulata et al, 2010). 

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). 

Field Pea Flours in Pasta. Incorporation of non-wheat flours into noodles improves the protein content and quality, but may have an adverse effect on the flavor and texture of the pasta. Hannigan (38) reported that 10% substitution of wheat flour with pea or soy flour resulted in satisfactory quality of Japanese Udon noodles. 

Nielsen et al. (39) used pea flour and pea protein concentrate, both cooked and raw, in noodles and spaghetti. The pasta was made from composite flours prepared by blending 33% pea flour with 67% wheat flour or 20% pea concentrate with 80% wheat flour. Protein content of the fortified noodles was approximately one-third higher than the wheat flour noodles. Addition of pea flour reduced the cooking time, but resulted in a softer product and lower yield than the wheat pastas. Precooking the pea flour improved flavor and decreased noodle dough stickiness, but the texture and yield of the cooked pasta was still less than that of wheat products. 

Soy Protein Concentrates. Both non-functional (low or no solubility) and functional (good solubility, emulsification capacity, and dispersibility) soy protein concentrates (70% protein, dry basis) are commercially available for use in meat products (2-4, 6, j), 15) Normally, a highly functional product with no harsh or bitter flavors is desirable. When used to replace lean meat, non-hydrated concentrate can be used at levels up to 6-7% in finished nonspecific emulsion meats Higher replacement levels or formulas with specific cost/nutrition requirements may use soy protein concentrate with a judicious amount of textured soy protein (6). Excellent yields, cost savings, texture, flavor and nutrient profiles are possible. However, most soy protein concentrates lack sufficient solubility or sufficiently low viscosities to be used in brines for absorption or injection into whole muscle tissue. When legal standards for protein content exist (13), more concentrate must be used to achieve legal minimums. Brine viscosities increase and uniform distribution of brine components throughout the specific whole muscle piece is restricted. Finished product appearance and flavor are easily compromised. Thus, use of soy protein concentrates in whole muscle applications is limited. 

When texturized soy protein was used to replace some of the meat in patties, undesirable off-flavors were released during preparation and consumption of the meat-soy mix (3). The source of these were identified as oxidation products of unsaturated fatty acids. High protein content soy ingredients have mitigated this problem (4j. 

Depending on the relative amylopectimamylose ratio found in the rice, the starch can exhibit a variety of gelatinized textures and strengths, as well as resistance to acid. Overall, there are several basic factors that affect starch performance. These factors, which include rice variety, protein content, method of starch production and modification, are described below. 

These products are usually made from formulations of high protein content (soya, meat particles, etc.), so the continuous phase at the die exit is proteinaceous, with inclusions of carbohydrate. These products are required to deliver a significant textural strength (bite) even when fully hydrated. Massive expansion and low bulk density is not required. Instead, a degree of fibrosity (anisotropic structure) is required to simulate meat. The early structures were extruded by processes similar to those discussed above, but with a deliberately low expansion. This was achieved by extruding with a higher moisture content and die exit temperatures below 100°C (Cheftel et al. 1992 Liu et al. 2005). 

Established knowledge is also that the protein content is an important factor. In regular yoghurt manufacture, the dry matter or protein content is normally increased by l%-3% to obtain the required textural attributes, the processing means presented above being options to lower the required protein addition to the minimum. 

SPCs for food use. Defatted SFs were acid-leached and then neutralized before drying. With this development, SPCs were rapidly accepted as food ingredients, intermediate (between SF and SPI) in cost, protein content, and flavor. Cooking-texturizing extruders also were introduced at about this time and enabled the production of texturized SF or SPC for use as meat analogs at appreciably lower costs than those produced by the SPI spinning process. 

Texturized SFs or SPCs may be rehydrated to 18% protein content (60 to 65% moisture content) and used at levels up to 30% reconstituted soy protein in ground meat blends and hamburgers. In domestic practice, however, the reconstituted portion... 

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. 

The textural (stickiness and consistency on cooking) and physiochemical properties of rice could not be explained on the basis of the total amylose content but these properties correlated well with the insoluble amylose content. The protein content had no effect on these properties. A cross-linked amylose has been used as a substrate to determine the a- and )3-amylase activities of amylo-lytic preparations. ... 

Soy protein concentrates typically contain 70% to 72% crude protein. For example, bacon strips can be made by a texturization processes involving twin screw extrusion (19). The high-protein content yields the protein as the continuous phase. Note that soy beans, like most seeds, also contain some triglyceride oils, important in cooking the final product. 

The required protein content of the starting material varies and depends on the process used for texturization. The starting material is often a mixture such as soya with lactalbumin, or protein plus acidic polysaccharide (alginate, carrageenan or pectin). 

Soy protein is available to the food industry in a multitude of forms, most of which may be classified according to protein content as (1) soy flour and grits, containing 40 to 50% protein (2) soy protein concentrates, with about 70% protein (3) soy protein isolates, with 90 to 95% protein and (4) textured soy protein, which is made from one or more of the other three types. Fig. S-26 shows an attractive meat-substitute dish. 

Texture of the ripened grain— Wheat is classed as hard or soft. Hard wheats tend to be higher in protein content than soft wheats, and are primarily used in bread flour. Durham wheats are also hard wheats, used for macaroni production. Softer wheats are lower in protein and are chiefly milled into flour for cakes, cookies, pastries, and crackers. 

---