Fats and surfactants

Fats and emulsifiers affect paste viscosity and can modify mouthfeel by smoothing and shortening starch pastes. The effects are mostly due to physical blending, but may involve specific complexes. Interactions between starch and lipids are complicated and vary with the ingredients involved and the conditions under which 

Polysaccharides, including starches and dextrins, have been shown to reduce the volatility of aroma compounds, such as limonene, isoamyl acetate, ethyl hexanoate and beta-ionones.237 

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Although soaps have many physical properties in common with the broader class of surfactants, they also have several distinguishing factors. First, soaps are most often derived direcdy from natural sources of fats and oils (see Fats and fatty oils). Fats and oils are triglycerides, ie, molecules comprised of a glycerol backbone and three ester-linked fatty oils. Other synthetic surfactants may use fats and oils or petrochemicals as initial building blocks, but generally require additional chemical manipulations such as sulfonation, esterification, sulfation, and amidation. 

Sulfated Natural Oils and Fats. Sulfated natural triglycerides were the first nonsoap commercial surfactants introduced in the middle of the nineteenth century. Since then sulfates of many vegetable, animal, and fish oils have been investigated (see also Fats AND FATTY oils). With its hydroxyl group and a double bond, ricinoleic acid (12-hydroxy-9,10-octadecenoic acid) is an oil constituent particularly suited for sulfation. Its sulfate is known as turkey-red oil. Oleic acid is also suited for sulfation. Esters of these acids can be sulfated with a minimum of hydrolysis of the glyceride group. Polyunsaturated acids, with several double bonds, lead to dark-colored sulfation products. The reaction with sulfuric acid proceeds through either the hydroxyl or the double bond. The sulfuric acid half ester thus formed is neutralized with caustic soda ... 

Presents a global forum for the science and technology of fats, oils, surfactants, and related materials. 

This group of ingredients has many useful properties. Alcohols and phenols are very common in household products. Alcohols are good solvents and are used in perfumes and flavorings to dissolve fats and oils. Heavier alcohols with long chains of hydrocarbons act as emulsifiers and surfactants, bringing oil and water together. 

The C10-C,8 fatty acids and fatty acid methyl esters, important intermediates for the production of surfactants, are almost exclusively produced by hydrolysis or a transesterification reaction of animal or vegetable fats and fatty oils. 

In anticipation of a more balanced discussion on renewable and fossil resources for surfactants a consensus on the coexistence of petrochemically derived products and products based on, for instance, oils, fats, and carbohydrates can be predicted. 

Ester sulfonates will become more and more interesting in the future because the raw materials for their preparation are fatty acid esters which can be prepared from oils and fats, and thus from renewable resources. They can be used as possible substitutes for surfactants based on petrochemicals. 

Compared with the fatty alcohol sulfates, which are also oleochemically produced anionic surfactants, the ester sulfonates have the advantage that their raw materials are on a low and therefore cost-effective level of fat refinement. The ester sulfonates are produced directly from the fatty acid esters by sulfona-tion, whereas the fatty alcohols, which are the source materials of the fatty alcohol sulfates, have to be formed by the catalytic high-pressure hydrogenation of fatty acids esters [9]. The fatty acid esters are obtained directly from the fats and oils by transesterification of the triglycerides with alcohols [10]. 

Carboxylates (9.4, where R is the long-chain hydrophobe and X the cation) represent the oldest type of surfactants, since they could be obtained from naturally occurring fats and oils long before the advent of the petrochemical industry sodium heptadecanoate (9.5), for example, incorporates the cetyl group as hydrophobe. Sodium stearate, sodium palmitate and sodium oleate are the simplest carboxylates generally used as surfactants. Alkylaryl compounds (9.6) are also known. 

Alcohols in the range C12—Ci8 are important raw materials for the production of a key group of surfactants ethoxylates, sulfates and ethoxysulfates among others. Alcohols used in the surfactant industry are primary, linear, or with different degrees of branching, and they can be produced from either petrochemical sources (ethylene or linear paraffins) or from oleochemical products (animal fats and vegetable oils). 

Although supercritical CO2 is an effective solvent for oils, fats, and similar substances, it is a poor one for nonvolatile hydrophilic (water-loving) substances such as proteins or metallic salts. Adding water as such to the supercritical CO2 is of little help, as the solubility of water in it is limited. Johnson and co-workers216 overcame the latter limitation by forming water-in-C02 emulsions with the aid of an added nontoxic perfluoropolyether surfactant that forms reverse micelles around the water microdroplets, in effect combining the special properties of supercritical CO2 with the solvent power of water. These emulsions can dissolve a variety of biomolecules at near-ambient temperatures, without loss of their biological activity. 

Figure 8.15 Cartoon showing how proteins, polysaccharides and surfactants (emulsifiers) might be distributed at the triglyceride-water interface. Inter-facial complexation in vivo between adsorbed protein and charged polysaccharide in the gastrointestinal tract could affect digestion of protein and fat by forming structures that inhibit the accessibility and activity of enzymes (proteases and lipases). Reproduced from Dickinson (2008) with permission.

Sulfonic acids and sulfonate salts contain the -S03H and -SO) groups, respectively, attached to a hydrocarbon moiety. The structural formulas of benzene sulfonic acids and of sodium 1 -(p-sulfophenyl)decane, a biodegradable detergent surfactant, are shown in Figure 1.19. The common sulfonic acids are water-soluble strong acids that lose virtually all ionizable H+ in aqueous solution. They are used commercially to hydrolyze fat and oil esters to produce fatty acids and glycerol used in chemical synthesis. 

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