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.     

Defatted soy flour and grits

Defatted soy flour and grits are the most rudimentary forms of high protein products processed from the soybean, yet they are the soy products used in the largest volume by the food industry. To appreciate fully the contribution of defatted soy flour and grits to any food system, it is essential that a knowledge of the composition, nutritional value, and functionality of these products be well understood. Major emphasis is given to applications for defatted soy flour and grits with cereals.     

Processing of edible peanut flour and grits

Edible peanut flour and grits have been produced by a commercial prepress solvent extraction method. The finished flour exhibits excellent extrusion-expansion characteristics for use in both cereal and snack food items. Soluble carbohydrate profile indicates peanut flour is lower in raffinose and stachyose than commercial soy flour. The bland flavor and light tan color facilitates incorporation of peanut flour and grits into a wide range of food products. One of seven papers presented at the Symposium, ”Processing Methods for Oilseeds”, AOCS Spring Meeting, April 1973.     

Soy flour in European-type bread

Effect of soy flour, soy protein concentrate, and isolate on dough and loaf properties of breads produced from flour, yeast, salt, and water with no shortening or added improvers was investigated. Wheat flour, rye flour, and mixtures of the two were included in the studies. Three wheat flours, varying in baking quality and extraction, ash content 0.65 and 0.80%, were used; 1.5, 3, and 5% soy products, flour basis, were added. Water absorption increased 3.8–4.7% at the 3% soy level and 6.1–7.3% at the 5% level of soy product addition. Dough development time and stability were increased and dough softening reduced. Dough gassing power increased ca. 7–25%. By using a shorter proofing time, more intensive mixing, and the sponge dough process, loaves only slightly smaller in volume than the control were obtained at the 3% soy level. Panel evaluations scored bread highest with 1.5 or 3% soy flour and that with 3 or 5% soy protein concentrate as lowest, but acceptable. Use of 2% lard as shortening, or 2% lard plus emulsifier, produced soy breads of excellent quality and ca. 25% higher loaf volume than controls.     

Oilseed protein concentrates and isolates

Much attention has been focused on the oilseed crops as an alternate and largely untapped source of food protein in an endeavor to provide needed nourishment for large segments of the world’s expanding population. A significant part of this attention has been devoted to the practical concentration and isolation of the proteins of several oilseeds. As a result of intensive effort during the last decade, soy protein concentrates and isolates are now commercial commodities which are gaining increasing acceptance as useful functional and nutritional ingredients for food. This report is concerned with a brief review of the commercial processing, product characteristics and food utilization of soy protein concentrates and isolates. In addition, pertinent comments on the concentrates and isolates of other oilseed are included. One of 21 papers presented at the Symposium, “Oilseed Processors Challenged by World Protein Need,” ISF-AOCS World Congress, Chicago, September 1970.     

Soy products in bakery goods

Applications of soy proteins in baking are reviewed and original data on taste and texture tests are presented. New foods employing soy for nutritional improvement are described. A plea is made for production of soy proteins with higher baking functionality and improved taste.     

Soya products in meat,poultry and seafood

The soya protein industry has produced a wide variety of products with specific functionality properties to meet the targeted needs required by the food industry. It is important to recognize that certain of these soya protein products have and perform specific functions in these foods, such as texture forming, gelation, fat and water binding, and emulsification. They contribute to the nutritional and general overall eating quality. Also important is to recognize the limits of application of soya protein technology based on maintaining the traditional quality of the meat, poultry or seafood products. Today, unlike just a few years ago, soya protein products are able to contribute to, not just extend, high-quality meat, poultry and seafood products. The combination of resource efficiency of soya proteins and new technological advances is constantly expanding the long list of applications worldwide. The function of soy protein products in a variety of processed meat, poultry and seafood products is discussed. Paper presented by C.W. Kolar.     

Soy protein products and their production

The soybean industry in the U.S. started in the first years of this century and was only 5,000,000 bushels just 50 years ago. This year it is expected to be over 1.5 billion bushels, reflecting a remarkable growth. Beans are processed primarily for soybean oil and for meal to be used in poultry and livestock feeds. Only ca. 3% soy protein is used in human food today. Special processing is required to prepare proteins to meet the various specifications of products for the food industry. Methods used to produce flour and grits, spun fibers, textured proteins, concentrates, and isolates are described.     

Soy protein products in other foods

Both long-term and emerging patterns of utilization underscore the diversity of the use of soy protein products in processed foods other than meat foods. The purpose of this paper is to present a selective overview of this diverse usage.     

Vegetable proteins in meat products,problems and possibilities

The author considers the use of vegetable protein products in the meat industry promising. Development will probably be slower than anticipated, but the use is likely eventually to become quite substantial. One may even anticipate products which replace certain traditional meat products altogether. Nutritionally such development would be completely acceptable. It should also be acceptable from a consumer’s point of view, provided adequate information is given in each case. In this respect one may note that information given to the consumers about the composition of traditional or contemporary mixed meat products is quite inadequate in many instances. The specific restrictions often placed on the use of vegetable protein products appear as adherence to tradition more than a real concern for consumer’s protection or health.     

Lipid oxidation in meat and meat products—A review

Lipid oxidation is a major cause of deterioration in the quality of meat and meat products. Oxidation can occur in either the stored triglycerides or the tissue phospholipids. Ferric heme pigments have been implicated as the major prooxidants in tissue lipid oxidation. Pigment and lipid oxidation are interrelated, and ferric hemes are believed to promote lipid oxidation. The resulting oxidation destroys the hemes. Nonheme iron and ascorbic acid may also function as prooxidants in meat. Sodium chloride accelerates oxidation of the triglycerides, although the mechanism of salt catalysis is not completely known. Cooked meat undergoes rapid deterioration due to tissue lipid oxidation. The meat pigment in the cured pink ferrous form does not promote the rapid oxidation undergone by cooked uncured meat. Refrigerated and frozen fresh meats are also susceptible to lipid oxidation. Protein denaturation and cross-linking may result from lipid oxidation in stored freeze-dried meat. With increased consumption of prepackaged raw meat and precooked convenience meat items, control of oxidation has become increasingly important. Antioxidants and chelating agents are the most effective inhibitors of lipid oxidation. One of 28 papers presented at the Symposium, “Metal-Catalyzed Lipid Oxidation,” ISF-AOCS World Congress, Chicago, September 1970.     

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.     

Neutral lipids of chickpea flour and protein isolates

The neutral lipids composition of defatted chickpea flour and two types of protein isolates has been studied. The main compounds in neutral lipids are triacylglycerols, free fatty acids, and diacylglycerols. Other compounds present are wax esters, free fatty alcohols, and free sterols. The main fatty acids in neutral lipids are C_18:2 and C_18:1 among the unsaturated, and C_16:0 and C_18:0 among the saturated acids. Free and esterified alcohols range from C_16:0 to C_28:0, the majority being those with an even number of carbon atoms. Sterols observed are β-sito-sterol, campesterol, stigmasterol, and δ-5-avenasterol. Triacyl-glycerols are partially hydrolyzed, and the amounts of unsaturated sterols and unsaturated fatty acids are reduced as a result of the chemical treatment during production of the protein isolates.