Texture, emulsion

Thickeners are applied in order to increase the viscosity of the continuous phase of the emulsion. Thus, the droplet movement is decreased, resulting in a reduced coalescence rate and sedimentation. At the same time the emulsion texture is changed. 

Pasteurized Process Cheese. Sodium citrate is used in pasteurized process and sHced cheese as an emulsifying salt to stabilize the water and oil emulsion and improve process cheese body and texture (64). 

Schicht-pressen, n. laminate molding, -pres(s)-stoff, m. laminated plastic, molded laminate. -Seite, /. (Phatog.) emulsion side, -spaltung, /. delamination. -stoff, m. laminated ma terial. -textur, /. stratified structure. 

What are they like to eat Humans are particular about the organoleptic properties of their food. Microbial cells may have little taste or smell, or even smell or taste unpleasantly to some people. The texture may not be the same as in conventional foods, particularly with unicellular organisms. These draw-backs can be overcome by adding a proportion of SCP to manufactured foods. However, even when SCP is incorporated into manufactured foods it may not have suitable characteristics such as stability, ability to bind water or fats, or ability to form gels, emulsions or foams. SCP for feed does not have to meet such strict requirements. 

Different polysaccharides change the perception of flavour, thus xanthan is superior to gum guar in the perception of sweetness. Mixtures of xanthan and locust bean gum have improved flavour release and texture when used in pies and pat s compared to starch. Many foods are emulsions, examples being soups, sauces and spreads. Exopolysaccharides are used to stabilise these emulsions and prevent the phases from... 

Manoi, K. and Rizvi, S. S. H. (2009). Emulsification mechanisms and characterizations of cold, gel-like emulsions produced from texturized whey protein concentrate. Food Hydro-colloids 23, 1837-1847. 

In the study by Thompson, et al. (11), the ml of gel released per 100 g emulsion for the reference emuTsion without soy, with soy isolate (SIF), soy concentrate (SCF) or soy flour (SF) was 6.07, 5.83, 5.49 and 3.08, respectively, when the hydration ratios were 1 4 (flourrwater) for SIF, 1 3 for SCF and 1 2 for SF. The ml gel released per 100 g emulsion containing 10, 15, 20, and 25% soy protein was 6.70, 5.01, 3.94 and 3.57, respectively. When soy protein concentrate was incorporated into an emulsion at the 3.5% level, the processing yields, textural profile and sensory textural attributes of frankfurters were not different among the products with and without added soy concentrate (13). An objective measure of compression and shear modulus indicated that soy protein concentrate incorporated into frankfurters at the 3.5% level had no effect on batter strength or texture ( M). The addition of a cottonseed protein to frankfurters to replace 5, 10 or 15% of the meat resulted in higher pH, less cured color, less firmness of skin, softer texture and reduced desirability as judged by a sensory panel (J5J. 

Textured Soy Proteins. Textured vegetable proteins, primarily textured flours and concentrates (50% protein and 70% protein, dry basis, respectfully) are widely used in the processed meat industry to provide meat-like structure and reduce ingredient costs (3-6, 9-10). Available in a variety of sizes, shapes, colored or uncolored, flavored or unflavored, fortified or unfortified, textured soy proteins can resemble any basic meat ingredient. Beef, pork, seafood and poultry applications are possible 03, 4-7, 15, 19) Proper protein selection and hydration is critical to achieving superior finished product quality. Textured proteins have virtually no solubility and, thus, no ability to penetrate into whole muscle tissue Therefore, textured soy proteins are inherently restricted to coarse ground (e.g. sausage) or fine emulsion (e.g. weiners and bologna) products, and comminuted and reformed (i.e. restructured) meat products. None are used in whole muscle absorption or injection applications (2-4, 6, 11). 

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. 

D.W. Stanley, H.D. Goff, and A.K. Smith Texture-Structure Relationships in Foamed Dairy Emulsions. Food Res. Int. 29, 1 (1996). 

Because of its gelling ability, carrageenan is widely used as food thickeners and emulsion stabilizers in the food industry and is present in many dairy products including less expensive ice-cream and other dessert products providing a smooth, creamy texture. It is used as a stabilizer in foods, such as chocolate milk. 

The term food colloids can be applied to all edible multi-phase systems such as foams, gels, dispersions and emulsions. Therefore, most manufactured foodstuffs can be classified as food colloids, and some natural ones also (notably milk). One of the key features of such systems is that they require the addition of a combination of surface-active molecules and thickeners for control of their texture and shelf-life. To achieve the requirements of consumers and food technologists, various combinations of proteins and polysaccharides are routinely used. The structures formed by these biopolymers in the bulk aqueous phase and at the surface of droplets and bubbles determine the long-term stability and rheological properties of food colloids. These structures are determined by the nature of the various kinds of biopolymer-biopolymer interactions, as well as by the interactions of the biopolymers with other food ingredients such as low-molecular-weight surfactants (emulsifiers). 

Most food products and food preparations are colloids. They are typically multicomponent and multiphase systems consisting of colloidal species of different kinds, shapes, and sizes and different phases. Ice cream, for example, is a combination of emulsions, foams, particles, and gels since it consists of a frozen aqueous phase containing fat droplets, ice crystals, and very small air pockets (microvoids). Salad dressing, special sauce, and the like are complicated emulsions and may contain small surfactant clusters known as micelles (Chapter 8). The dimensions of the particles in these entities usually cover a rather broad spectrum, ranging from nanometers (typical micellar units) to micrometers (emulsion droplets) or millimeters (foams). Food products may also contain macromolecules (such as proteins) and gels formed from other food particles aggregated by adsorbed protein molecules. The texture (how a food feels to touch or in the mouth) depends on the structure of the food. 

The huge variety of emulsions used as food, medicinal, cosmetic, and other industrial products make these colloids important practical systems in which the surface monolayers exert considerable influence. We have already discussed the use of lecithin to control the viscosity and the texture of chocolate in Vignette IV in Chapter 4. 

Diehl, K.C., Hamann, D.D., and Whitfield, J.K. 1979. Textural failure in selected raw fruits and vegetables. J. Texture Studies 10 371-400. Fligner, K.L., Fligner, M.A., and Mangino, M.E. 1991. Accelerated tests for predicting long-term creaming stability of infant formula emulsion systems. Food Hydrocolloids 5 269-280. 

The goal of food emulsion manufacturers is to produce emulsions that meet or exceed the expectations of their clientele. As a first step, companies typically conduct market studies to determine what these expectations are. Sensory evaluations are then used to translate these expectations into product-specific criteria (e.g., emulsion color, texture, appearance) that serve as guidelines to design the emulsification process and verify the quality of the produced emulsion. If emulsion properties comply with the set standards (i.e., their values are within an acceptable range), manufacturers can be confident that their customer base will be satisfied with the product. 

In the broadest sense, stability of emulsions should be defined as maintenance of an initial state that was attained after homogenization of the two (or more) liquids (Sjoblom, 1996). The initial state of the emulsion can be defined by a set of internal parameters. The primary parameters used to describe the state of an emulsion are droplet size distribution and concentration, since the bulk properties of emulsions such as color, texture, and taste are primarily a function of these two colloidal parameters (McClements, 1999). In selected cases it may be necessary to include additional parameters such as pH and microbial load to further define the initial state of the emulsion. 

Many food products (salad dressings, whipped toppings, ice cream etc.) are dispersed colloid systems, such as emulsions, suspensions or foams. Texture, structure and stability of these dispersions have fundamental importance for the food manufacturer. Our chapter presents new methods, most of them developed in our laboratory, and mechanisms which can be very helpful for the food researcher or developer. 

New experimental techniques and several of their applications were presented which help in the understanding of structure, texture and stability of food systems. For future research, the mechanism of film stability by the microlayering of colloid particles seems to be the most promising - especially in food emulsions and foams. Work is in progress in our laboratory to calculate the oscillatory disjoining pressure inside liquid films containing microlayers [30],... 

A range of methods are used to test the textural quality of whippable emulsions. These methods are used to quantify the mechanical properties of the various products. 

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