Spun-fiber textured products

The process for spinning fibers from soy isolate is described. Fabrication of so called food analogues and extenders containing spun soy fibers is reviewed. The rationale for the use of fibers in food products and ingredients is explored. Nutritional properties, especially protein quality, of the products are discussed. Emphasis is given to the fact that spun-fiber textured products contain a variety of items, such as soy, wheat, oats, egg albumen, yeast, sodium caseinate, and vegetable oils. The relationship of this variety to applied nutrition is discussed.     

Processing and product characteristics for textured soy flours,concentrates and isolates

During the last 25 years, the development of processes to provide textural properties in soy proteins has greatly increased the market potential for soy protein products. Many different processes based on soy flour, concentrates and isolates have been developed. They have ranged from products to be used in extension of meats to meat analogs themselves. The real success of new processes is measured by their success in the commercial marketplace. The most successful products have been based on thermoplastic extrusion of soy flour. More recently, second generation products made by the thermoplastic extrusion of soy protein concentrates have been introduced. These products have less flavor, wider variety of functional characteristics and greatly reduced flatulence characteristics compared to textured soy flour products. This paper describes processes used to texturize soy proteins and characteristics of the various products. Product characteristics, functionally and economics are key factors in deciding which product to use in end-product formulations. The wide variety of textured soy proteins available provides a product for each individual need.     

Textured and shaped oilseed protein food products

The major emphasis in developing textured and shaped protein foods has been with the use of soy proteins. The availability at a low stable price, the high protein content and quality, and the inherent chemical properties of the protein allowing for unique structure development are major reasons for its strong world-wide use. The changing economic trends of many basic protein foods are creating a need for the use of unique textured proteins either as ingredients in existing foods or allowing improved functionality in new products. The two main procedures for texturing and shaping oilseed protein are spinning of protein isolates, and direct extrusion of flour. The spinning technique is more expensive and has greater product functionality in contrast to the direct extrusion method. Consumer acceptance is in large part correlated with the technological success of imparting desirable colors, flavors and textural properties in the finished food product. Examples of these variations are given. The use level of these textured proteins, particularly in meat products, are restricted by labeling standards. The present regulations are not clearly defined. Current proposals for labeling textured vegetable proteins when used with meat products involve standards on a ratio to meat basis. One of 21 papers presented at the Symposium, “Oilseed Processors Challenged by World Protein Need,” ISF-AOCS World Congress, Chicago, September 1970.     

Texturized protein products

Texture is changed in oilseed protein fractions by mechanical and chemical means in specialized equipment. Processing conditions are closely controlled to ensure end product forms wanted. The arrangement of equipment used in the production of textured proteins is discussed as it relates to a commercial plant design. The nature of feed materials and details of processing conditions required to produce texture in soy protein are presented. Other forms of textured oilseed protein are discussed.     

Processing of lipoxygenase-free soybeans and evaluation in foods

Lipoxygenase-free soybeans were processed into flour, concentrate, and isolate and compared to normal soybeans in bread, meat patties, and a beverage, respectively. Bread made with 20% normal or lipoxygenase-free soy flour had greater (P< 0.05) beany flavor than control yeast bread. There were no differences in beany flavor scores between soy flour types, normal and lipoxygenase-free. Ground beef patties made with 5% acid-washed or ethanol-washed soy protein concentrate had greater (P<0.05) beany flavor than control ground beef patties. Ground beef patties made with ethanol-washed concentrate were scored lower in beany flavor than those made with acid-washed concentrate from normal soybeans. There were no differences in beany flavor between normal and lipoxygenase-free soy isolate in 2%-fat or no-fat beverages. Comminuted meat products made with lipoxygenase-free soy proteins, especially ethanol-washed concentrate, have potential for making soy foods with less beany flavor than foods made with normal soy.     

Soy protein in school feeding programs

Textured vegetable protein has been a tremendous asset to the Memphis school feeding program. There are several reasons for this: (A.) it is a dry product, easy to handle and store; (B.) shelf life is long enough to permit quantity purchasing and warehousing; (C.) dry storage of textured vegetable protein is much cheaper than refrigerated storage of meats; (D.) our students have not objected to its use; (E.) the absorption qualities of the textured vegetable protein allowed us to purchase ground beef with a 30% fat content, rather than a 22% fat content; (F.) it allows a more innovative approach to school food services; and (G.) it saves money. The introduction of textured vegetable protein into our operations has saved the U.S. school lunch program millions of dollars.     

Comparative functionality of soy proteins used in commercial meat food products

The use of soy isolates, concentrates, and texturized flours in meat food products is discussed. Functional characteristics of soy products in relation to their market application are reviewed. Soy isolates find more limited usage in meat food systems (2%) than the concentrates and textured soy flours (8–12%). In weak meat systems containing large amounts of fat (30–45%), the concentrate emulsifier and isolate are more important than the texturized soy flour. In chopped meat systems with 18–25% fat, the textural properties of soy flour (extruded) are more important than the use of an isolate. However, combinations of concentrate emulsifier and texturized flour are used. The method of cooking, i.e. fresh, deep fat-fried, or char-broiled, will affect the usage of soy combinations. In comminuted cooked cured meat food mixes, soy concentrates, and textured flours currently are being used. Nutritional properties are improved by inclusion of available ingredients high in lysine and methionine. Functional measurements of textural properties have been completed using the Instron with a Lee Kramer cell. Both model emulsion systems and finished product results substantiate the accuracy of textural properties in soy-meat mixes using the Instron.     

Use of vegetable protein in processed seafood products

In comparison to other muscle foods like red meats, utilization of vegetable protein products in seafood is limited, and can be considered to be in its infancy. The opportunities are not predicated entirely on the future. Opportunities exist today, and vegetable protein products such as soy can and will impact on the seafood market. The opportunities for soy protein products in seafood are and will be realized in terms of nutrition, functionality, and economics. The change in price of frozen fish paste caused by the influence of the 200-mile zones was 2 to 2.5 times in one year. In contrast, the price of soy protein products has not changed during the same period. Obviously, this price difference has an important impact on the demand for soy protein products. As the price of fish in Japan has risen, consumers have tended to avoid buying fish products, and there has been a trend toward buying animal products. Consequently, the use of textured soy proteins in these animal protein foods has also increased. Japan has a long and well developed tradition of eating soybean foods, and at the same time, Japan possesses a high level of scientific technology concerned with new soy protein foods. The whole nation, including the consumers, producers, academic societies and the government, is of the consensus that soybeans are a good food source whose consumption should be encouraged and increased. In spite of such favored conditions, utilization of soy protein foods in Japan has not really taken off even after almost 20 years of development. Reasons for the slow expansion of the market are many. However, the definite factor which decisively affects the increased use seems ultimately to be a balance between the quality and price of the products. In Japan the balance would become favorable to soy protein because of the limited fish resources as well as recent advances in the technology of soy protein foods. Several formulations for fish/soy products are presented.     

Interaction between dietary protein and fat in triglyceride metabolism in the rat: Effects of soy protein and menhaden oil

The objective of the present study was to determine the mechanisms by which dietary proteins interact with dietary lipids in the regulation of triglyceridemia in rats. Male Sprague-Dawley rats (n=56) were subjected to 28-d experimental diets containing different combinations of proteins (20% w/w) and lipid sources (14% w/w): (i) casein-menhaden oil, (ii) casein-beef tallow, (iii) soy protein-menhaden oil, and (iv) soy protein-beef tallow. Significant protein-lipid interactions were observed on triglyceridemia and hepatic cholesterol in fasted rats. The combination of casein and beef tallow was associated with high plasma TG and hepatic cholesterol concentrations, which were reduced by substitution either of soy for casein or of menhaden oil for beef tallow. Therefore, triglyceridemia and liver cholesterol remained low with soy protein feeding, independently of the lipid source, as well as with menhaden oil feeding, regardless of the protein source. The menhaden oil diets reduced plasma cholesterol, hepatic TG, and TG secretion compared with beef tallow diets independently of the dietary protein source. Modifying the source of dietary proteins and lipids had no effect on post-heparin plasma lipoprotein lipase activity. These results demonstrate that soy protein can lower rat triglyceridemia relative to casein when associated with beef tallow consumption, whereas menhaden oil can attenuate hypertriglyceridemia when rats are fed casein. The data further suggest that part of the hypotriglyceridemic effect of soy protein in the rat may be mediated by reduced hepatic lipid synthesis, as is the case for menhaden oil.     

Meat and vegetable protein blends for engineered foods

The meat industry in the United States offers the biggest volume potential for vegetable protein. American Meat Institute reports a 1977 tonnage of 4,377,937,031 pounds of sausage products. Our research with various protein sources is discussed. Emphasis is placed on soy protein products currently available and approved by government agencies. Formulations and requirements for satisfactory products is outlined with economic justifications for soy flour, concentrates and isolates. A thorough discussion of extruded and/or engineered foods is presented showing utilization of mechanically deboned meats, recovered meat proteins from pork and beef rendering, and vegetable proteins in combination with beef and pork. The nutritive values of mechanically deboned chicken and structured soy protein gave PERs over 3.0 with good amino acid balance.     

Soy protein foods in U.S. assistance programs

Soy protein food products occupy an important place in both U.S. overseas and domestic food assistance programs. In the overseas food donation program the products serve as the source of protein for the fortification of conventional processed commodities—wheat flour, corn meal, rolled oats, bulgur, and sorghum grits—and as a major source of protein in several cereal soy products designed for special use as child food supplements. Acceptance of these products has been good and more than 1 billion lb. of soy-fortified foods were distributed in the overseas program during July 1, 1972-June 30, 1973. In domestic food assistance programs, soy protein foods which meet U.S. Department of Agriculture requirements have been introduced into both school lunch and breakfast programs and also are distributed to needy families. Two products, textured soy protein and protein-fortified enriched macaroni, are permitted to meet part of the meat requirement in the Type A school lunch. In the school breakfast program, soy protein is a permitted ingredient in protein-fortified foods such as doughnuts, cake-like baked products, and cereal-fruit products. They were introduced primarily to meet the need for nutritious food items that require no kitchen facilities to prepare and are convenient to serve in schools that lack food service facilities. Specifications for the various food products are presented.     

Nutritional aspects in textured soy proteins

Textured soy protein products have found extensive use in pet foods and many human foods. They extend and complement meats in formulated foods. Numerous feeding tests with people and experimental animals show that biological values are high and protein efficiency ratios compare favorably with pure meat products. By careful processing of the textured soy products, high quality, safe, low cost protein food can be prepared. Textured soy proteins are an excellent example of man’s creative ability to engineer a supplementary food that is nutritious, palatable, and economical.     

Effects of vegetable proteins on iron and zinc absorption and availability in humans

This review discusses research on the effects of vegetable protein diets on iron and zinc absorption and availability. Constituents of vegetables can have either a positive or negative effect on iron absorption. Although the use of soy protein to extend beef patties was found to decrease nonheme iron absorption in some studies, the use of soy-extended beef on a regular basis was not found to deleteriously affect the iron status (serum ferritin levels) of adult men, menstruating females or school age subjects. Factors such as phytic acid level, dietary fiber content or protein source of vegetable protein diets have been implicated in decreasing the utilization of iron and zinc by humans. The effect of the molar ratio of phytate on the zinc of the diet is controversial: some studies find a decrease in zinc absorption with an increase in the phytate to zinc molar ratio; other studies find zinc absorption more dependent on the total amount of zinc in the meal than on the presence of phytic acid. Since many people meet their energy and protein requirements from vegetable sources, attention should be given to the mineral availability of these diets.     

Designing vegetable proteins to fit market needs

The needs and wants of the market are discussed as well as the regulatory practices that frequently inhibit the fulfillment of the market’s requirements. The advantages and short comings of the various types of protein ingredients are described, and appeals are made to the soy protein-producing industry to protect the integrity of traditional products by recommending extension of meat and other products in such a manner as to preserve their traditional character. Improved technical service offered to the food processors can bring added assurance to the consumer of a continuing supply of quality traditional products. The soy protein industry must continue the development of their own products so that broader application is possible. The inherent nutritional and functional values of soy proteins are such as to make a new generation of textured products, and improvement in the functional properties of concentrates and isolates a very realistic goal. Compatibilities of soy proteins with other proteins and ingredients are discussed; suggestions are made that the inherent synergism in many of these combinations is an untapped developmental area that will enable us to design protein ingredients for specific applications and thus benefit the consuming public, as well as the food processing industry.     

Soy flour and grits for use in food products

Processing alternatives enable the soybean processor to manufacture soy flour products which vary in fat content, granulation and degree of heat treatment. By controlling these variables, the processor is able to regulate the nutritional value and functional properties of these products. The application of soy flour products is dependent upon their functional properties, nutritional value and low cost. Currently, the major markets for soy flour and grits are in pet foods and animal feeds, cereal based foods and ingredients, meat based foods, and as a substrate for refined protein products such as the textured vegetable proteins, soy protein concentrates, isolates and hydrolysates. These soy protein products are generally marketed as functional and nutritional substitutes for meat, milk and egg protein. For example, soy flour is a functional replacement for milk in many cereal-based foods, e.g., bread, and also enhances the nutritional value of the cereal protein by supplying lysine to the formulation. The United States government has pioneered the development and marketing of protein-enriched, cereal-based foods designed to combat worldwide starvation. The government has directly supported the research and development of corn and wheat-based food substrates supplemented with soy flour, and has purchased over one billion pounds of these products since 1966 for worldwide distribution. One of 21 papers presented at the Symposium, “Oilseed Processors Challenged by World Protein Need,” ISF-AOCS World Congress, Chicago, September 1970.     

Entwicklung und Bedeutung pflanzlicher Proteine in der menschlichen Ernährung

Development and Importance of Vegetable Protein in Nutrition For several decades it has been a common practise to use concentrated vegetable fat and carbohydrate products in food processing, as well as institutional and house-hold food preparation. This is not true for vegetable protein products. Now, a new list of products are available, which have a wide protein range (50–90% crude protein) and which are ground, textured and spun and which have useful diversified functional properties. These products are finding a growing need and interests in the food industry. For 1975, the total U. S. consumption of soyprotein products reached about 170 000 t with an annual growth rate ranging from 3–25% for the individual types of products. The costs of the common soy protein products range from DM 1.50–5.30/kg crude protein for industrial uses in 1976. Comparing the costs for 100 g crude protein in soy products with other selected food items, which mainly cover the protein requirement, soy products range from 0.18–0.55 DM. This compares to a fraction of the protein costs of other foods. The principle functional properties, resulting from the protein dispersability and enzyme activity are: 1) 3–4 fold capacity to absorb moisture; 2) the emulsifying and stabilizing effects; 3) the improved fat-binding with meat products and 4) the reduced fat absorption with bakery products during frying. According to the “Ernährungsbericht 1976” of the DGE, growing importance has to be paid to an increased consumption of vegetable protein sources for better nutrition.     

Soy processing: From beans to ingredients

Soybean processing does not end with the products oil and meal. To the food ingredient business, this is only the beginning. This presentation is a simplified general scheme to show the processing of soybeans from the whole bean to each of its end protein ingredients and to show where they might fit into the food business. It portrays bean preparation and oil extraction, meal handling, and conversion of the meal into food ingredients. Soy flour, soy concentrates, soy isolates, and modified protein products, such as spun fibers and textured vegetable protein products, are covered. Some values and applications of the ingredients also are discussed. One of 13 papers presented in the symposium, “Soy Protein,” at the AOCS Spring Meeting, Mexico City, April 1974.     

Technische Probleme und Lösungen bei der Gewinnung von Sojaproteinen

Technical Problems and Solutions in the Recovery of Soy Proteins Soy proteins are interesting as food ingredients for economic and technical reasons. High yields per hectare, easy availability, low transport- and storage costs and low processing costs are favourable economic factors. The technical i. e. nutritional, functional and organoleptic properties influence each other. To optimize these properties for the specific applications, the proteins should be refined. The non-refined soy protein products i. e. defatted flour and textured flour have limited application. However the refined products i. e. concentrates, isolates and their textured forms, offer far better possibilities for the food industry.     

Twin-screw extrusion texturization of extruded-expelled soybean flour

Texturized soy proteins (TSP) have been produced from hexane-extracted soy flours having a narrow range of characteristics. The objective of this study was to determine the influence of protein dispersibility index (PDI) and residual oil content on extrusion texturization of partially defatted soy flours produced by extruding-expelling (E-E). Ten E-E processed soy flours having residual oil contents and PDI values of 5.5–12.7% and 35.3–69.1%, respectively, were texturized using a twin-screw extruder. Water-holding capacities were greater for TSP prepared from E-E processed soy flours with lower residual oil contents. Bulk densities were significantly lower for TSP prepared from E-E processed soy flours compared with a commercial product made from hexane-extracted soy flour. The texture characteristics of extended ground beef patties containing texturized E-E processed soy flour were similar to that of 19% fat ground beef. Flavor acceptability was directly correlated (R=0.761) with residual oil content of the E-E processed soy flours. However, lower residual oil and higher PDI flours exhibited better texturization and extrudate qualities.     

Meat and dairy analogs from vegetable proteins

The enormous pressures for protein food products in the coming decades, brought on by world population increases, will be solved through the extension of traditional animal protein foods with vegetable proteins and through the development of food products based on vegetable proteins alone. Analogs of beef, fish, poultry and other traditional animal protein products, which are based solely on vegetable proteins, are an established food category, and are expected to increase market share. Dairy analogs based on vegetable cow’s milk and dairy desserts. Vegetable forms of cheese and other milk protein products are also expected to increase. Nutritional equivalence of vegetable protein products is fundamental to product design. Protein and fat content must be standardized. Vegetable proteins are blended to reach desirable protein quality. Analogs currently marketed are primarily blends of soy and wheat proteins containing lesser amounts of yeast and egg albumen. The products are fortified with vitamins and minerals to levels present in animal protein foods. Processed meat manufacturing facilities, which exist in most developed countries, can be readily adapted to produce meat analogs. The technology which has been developed to date is based on soy or soy/wheat combinations. The technology can readily be adapted to other vegetable proteins such as rapeseed, cotton-seed, sesame or sunflower. These protein sources, while in abundance in many countries, need process research which can refine them for human use. The vegetable proteins offer the world’s exploding population a virtually untapped resource for its burgeoning food requirements.