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Glycerol monostearate (GMS) Polyoxyethylene monoglyceride (EMG)

Lactylated monoglyceride (LacMG)

Acetylated monoglyceride (AcMG) Propylene glycol monostearate (PGMS)

Figure 3. Nonionic emulsifiers based on glycerol esters and derivatives.

mercial GMS, for example, may contain as little as 65% stearate, if made from fully hydrogenated lard, or as much as 87% stearate, if made from fully hydrogenated soybean oil. The other principal saturated fatty acid will be palmitic, and because hydrogenation is practically never carried out to the extent that all unsaturation is removed (iodine value of zero), a small percentage of unsaturated (oleic and elaidic) acid is also usually present. Iodine values for powdered distilled monoglycerides (monoglyceride in a beaded form that hydrates readily when incorporated in a bread dough) are in the range of 19 to 36, and for plastic monoglycerides a typical range is 65 to 75. The unsaturated fatty acids are a mixture of oleic and linoleic and the trans isomers of these acids.

The product of the manufacture of ethoxylated monoglyceride (EMG) is somewhat random in structure. Monoglyceride is treated with ethylene oxide gas under pressure in the presence of alkaline catalyst at elevated temperatures. Ethylene oxide polymerizes via a series of ether linkages and also forms ether bonds with the free hydroxyl groups on the monoglyceride. The average number of ethylene oxide units per monoglyceride molecule is about 20 units (n = 20 in Fig. 3), distributed between two chains if the monoglyceride is doubly substituted. Chains may be attached to hydroxyls at both the two and three positions of the monoglyceride, although many more chains will be located at the a (three) position than at the fi (two) position because of the difference in their chemical reactivities. The exact distribution of polymer chain lengths and distribution between a and [i positions are functions of reaction conditions, for example, catalyst type and concentration, gas pressure, temperature, agitation, and length of reaction time.

The second group of monoglyceride derivatives, the attending emulsifiers (lactylated monoglyceride, acetylated monoglyceride, and PGMS), find their main use in cake production. These emulsifiers are dissolved in the short ening phase of the cake formulation and contribute to the emulsification of the shortening in the water phase as well as promoting incorporation of air into the fat phase. The particular property of these emulsifiers that makes them valuable in liquid shortening cakes is that they form a solid film at the oil water interface, not only stabilizing the emulsion but also keeping the lipid phase from preventing air incorporation (protein-stabilized foam formation) during cake batter mixing.

Sorbitan Derivatives. When the sugar alcohol sorbitol is heated with stearic acid in the presence of a catalyst, two reactions occur: sorbitol cyclizes to form the five-membered sorbitan ring and the remaining primary hydroxyl group is esterified by the acid. The resulting sorbitan monostearate (Fig. 4) is oil soluble, has a rather low hydrophilic lipophilic balance (HLB) value, and is the only one of the many sorbitan esters explicitly approved for food use in the United States (sorbitan tristearate is marketed as a crystal modifier, as a self-affirmed GRAS material). Other sorbitan esters of importance are the monooleate and the tristearate. Any of the three esters may be reacted with ethylene oxide to give polyoxyethylene derivatives, as indicated in Figure 4 which are water soluble and have a relatively high HLB. The monostearate derivative is known as Polysorbate 60, the tristearate is Polysorbate 65, and the monooleate is Polysorbate 80. The remarks made in connection with EMG regarding the length and location of the polyoxyethylene chains apply to these compounds. The average number of oxyethylene monomers per sorbitan ester molecule is 20 (n = 20), and in the case of the monoesters, chains of varying length (but with about 20 ethylene oxide units in aggregate) may be attached to more than one hydroxyl group of the sorbitan ring (triester has only one hydroxyl group available for derivatization).

Sorbitan monostearate is used in applications where fat is the continuous phase, that is, in fat-based confectionery

Homemade Pet Food Secrets

Homemade Pet Food Secrets

It is a well known fact that homemade food is always a healthier option for pets when compared to the market packed food. The increasing hazards to the health of the pets have made pet owners stick to containment of commercial pet food. The basic fundamentals of health for human beings are applicable for pets also.

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