Biomedical Engineering Reference
In-Depth Information
the long-chain fatty acid groups and the degree of acetylation. By these changes,
GMA has been made with a melting range of -24 to 54°C.
For food uses, GMA may be classified as nongreasy, plastic fats of relatively
sharp melting points for use in protective coating materials; low-melting fats with
extraordinary resistance to oxidativerancidity; low melting point oils with good
resistance to oxidative rancidity, and either liquid or plastic at below freezing point
temperatures. Over the past two decades GMA has found a number of uses in foods.
Solid GMA products are used as coatings for fruits, nuts, frozen baked goods, meat,
and meat products where thin films form oxygen and moisture barriers. Liquid GMA
products are used as release agents in candy production and as food lubricants in
nuts, raisins, and related products. Spraying the inside of ice cream sugar cones with
liquid GMA has been reported to extend shelf life. GMA products belong to the
group of emulsifiers that maintains their stability in the flexible alpha-crystal form.
These types of compounds improve agglomeration and thus the whippability and
foam stabilization of various food emulsions, such as those found in whipped
toppings and other dessert products. Other uses include plasticizers for chewing
gum, releasing agents, and defoamers. 121-123
Propylene Glycol Esters
Propylene glycol mono- and diesters are prepared by direct esterification of propy-
lene glycol with fatty acids. Their lipophilic quality makes them W/O emulsifiers.
For example, propylene glycol monostearate (PGMS) is a strongly lipophilic emul-
sifier, having a low HLB. 124 Propylene glycol fatty acid esters are listed among the
emulsifiers that may be added to fats at the manufacturer's level and have been
approved by the FDA for use in foods. 125 PGMS and propylene glycol monopalmitate
are most often used in cakes, cake mixes, whipped toppings, and bread. 126 Other
uses are in combination with distilled monoglycerides to obtain excellent batter
behavior resulting in increased cake volume and uniform structure and whipped
toppings (due to their aerating and foam stabilizing properties).
Stearoyl Lactylates (SL)
Stearoyl lactylates (SL) are made by the reaction of lactic acid, fatty acids, and a
suitable sodium or calcium source, at elevated temperatures and controlled condi-
tions under vacuum and nitrogen. The products are known as sodium stearoyl-2-
lactylate (SSL) and calcium stearoyl-2-lactylate (CSL), respectively. Figure 7.6 illus-
trates the process and the internal product composition of the reaction mixture. SSL
and CSL have been approved for use as dough conditioners in yeast-raised baked
products. These products combine two sets of properties: the ability to form a
complex withamylose improving bread shelf life and interacting strongly with gluten
to increaseloaf volume ( Figure 7.7 ). Other uses include whipped toppings, coffee
whiteners, cake icings, and starch puddings. 124,125,127,128
As emulsifying agents SL are used primarily in the baking industry as dough
conditioning agents. 105,128-130 More specifically, stearoyl-2-lactylate is used in non-
yeast leavened bakery products and prepared mixes, whereas stearoyl monoglyceridyl
 
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