Soybean proteins viscosity

Recently, a study was made of the electrophoretic as well as other physical and chemical properties of three types of soybean protein fractions (19). It was found that heating generally reduced the solubility of a suspension of these fractions and also increased their viscosity. These changes were attributed to subunit dissociation and aggregation. 

The rheological behavior of systems containing starch, soybean protein, soybean oil, and water (5 10 10 40) has been studied.1038 The viscosity of the system depends on the origin of the starch. For example, the viscosity of a potato-starch gel markedly decreases upon the addition of protein. In contrast, a cornstarch gel is much more stable and does not show a decrease in viscosity after the addition of protein. The incorporation of proteins into a lipid-starch system shows that proteins are distributed among both components of the system.885... 

Properties Colorless liquid. D 1.0518 (25/25C), bp 205-206.5C, crystallizing point -37C, flash p 205F (96C) (COC), refr index 1.4301 (25C), surface tension 30 dynes/cm (25C), viscosity 2.18 cP (25C), pH (anhydrous) 7.0 (pH of 10 solution in distilled water 4.2). Miscible with water and most organic solvents, resins, waxes, etc. slightly miscible with zein, beeswax, petrolatum immiscible with anhydrous glycerin, glue, casein, arabic gum, and soybean protein. Combustible. 

Alkalies and Acids. The older literature dealing with the treatment of soybean proteins with alkaline substances is quite extensive since these agents have often been used for protein extraction, solubilization, and property modification, including improved solubility, increased adhesive properties, and lower viscosity in dispersion and fiber formation (12, 21, 23, 24). The alkali treatment of soy protein for industrial use is done under conditions which are more severe (higher temperature and higher pH, such as possibly 50 °C at pH >13) than those intended for food usage. 

Acylation. The acylation of soybean proteins with various acyl halides and anhydrides of low and high molecular weight was initially evaluated for its impact on properties of industrial value such as viscosity in dispersion, adhesion, foaming, and detergency (21, 23, 24, 38). 

Liu, Z.S. S.C.K. Chang L.T. Li E. Tatsumi. Effect of selective thermal denaturation of soybean proteins on soymilk viscosity and tofu s physical properties. Food Res. Int. 2004,37, 815-822. 

Soybean protein is a very important binder type, especially in North America. It has properties very similar to those of casein. Isolated soybean proteins are hydrolyzed, isoelectric proteins. They are used in the form of alpha and delta proteins with four different viscosities (extra low, low, medium, and high). The viscosity refers to the dissolved soybean protein, the solvent of choice being aqueous ammonia (26 Be). Proteins dissolved in this way exhibit very low sensitivity to water after drying. like casein, soybean protein is mostly used as a mixture with polymer dispersions. This combination permits the preparation of coating colors with high sohds content and a relatively low viscosity. Solids contents ofca. 60%, suitable for blade coaters, can be achieved. 

Various modified viscose fibers, micromodal, and modal, for example, produced from beech were not studies for biostability. Information on biostability of artificial fibers produced from lactic casein, soybean protein, maize, peanut, and com is absent. 

Milk. Imitation milks fall into three broad categories filled products based on skim milk, buttermilk, whey, or combinations of these synthetic milks based on soybean products and toned milk based on the combination of soy or groundnut (peanut) protein with animal milk. Few caseinate-based products have been marketed (1,22,23). Milk is the one area where nutrition is of primary concern, especially in the diets of the young. Substitute milks are being made for human and animal markets. In the latter area, the emphasis is for products to serve as milk replacers for calves. The composition of milk and filled-milk products based on skim milk can be found in Table 10. Table 15 gives the composition of a whey /huttermilk-solids-hased calf-milk replacer, which contains carboxymethyl cellulose (CMC) for proper viscosity of the product. 

Regenerated proteins from casein (lanital), peanuts (ardil), soybeans (aralac), and zine (vicara) are used as specialty fibers. Regenerated and modified cellulose products, including acetate, are still widely used today and the production of fibers is similar to that described above for synthetic fiber production. Most regenerated cellulose (rayon) is produced by the viscose process where an aqueous solution of the sodium salt of cellulose xanthate is precipitated in an acid bath. The relatively weak fibers produced by this wet spinning process are stretched to produce strong rayon. 

Comminution also may be used to examine the stability of dispersed phases such as oil droplets. Depending on the viscosity of the product one simply mixes it or breaks it up in a solvent (usually water but, for example, use fresh soybean oil for chocolate), a buffer or the appropriate dyes (below). For instance, we mix easily dispersible foods (cream cheese, ice cream mix or tablespreads) with dyes on slides in a ratio of about 1 1 before examination. Where the dye is a diachrome (that is, highly colored) or is fluorescent in the absence of the substrate (for example, Acridine Orange) some attempt must be made to remove excess, uncomplexed dye molecules which might confound the interpretation. This can be done by reduction of the dye concentration or by making the preparation thinner. The advantage of these simple techniques is that a battery of microchemical tests to identify protein, lipid and carbohydrate can be completed on multiple samples in a very short time period. 

Non-dairy creams (cream alternatives) are O/W emulsions stabilized by milk proteins. A relatively thick adsorption layer provides stability, mostly by steric stabilization and partly by electrostatic stabilization [829]. Figure 13.3 shows an example of a soybean-oil and milk-protein emulsion stabilized by fat globules and protein membranes. Stabilizers, such as hydrocolloid polysaccharides, are added to increase the continuous phase viscosity and reduce the extent of creaming. They must be stable enough to have a useful shelf-life but de-stabilize in a specific way when they are... 

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