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Food Lipids: Chemistry, Nutrition, and Biotechnology

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Figure 17 Stereospecific numbering (sn) of triacylglycerols.<br />

In common nomenclature, esters are called � on primary <strong>and</strong> � on secondary<br />

OH groups. If the two primary-bonded fatty acids are present, the primary carbons<br />

are called � <strong>and</strong> ��. If one or two acyl groups are present, the term ‘‘partial glyceride’’<br />

is sometimes used. Nomenclature of the common partial glycerides is shown<br />

in Figure 18.<br />

St<strong>and</strong>ard nomenclature allows several different names for each triacylglycerol<br />

(TAG) [6]. A TAG with three stearic acid esters can be named as glycerol tristearate,<br />

tristearoyl glycerol, or tri-O-stearoyl glycerol. The ‘‘O’’ locant can be omitted if the<br />

fatty acid is esterified to the hydroxyl group. More commonly, triacylglycerol nomenclature<br />

uses the designation -in to indicate the molecule in a TAG (e.g., tristearin).<br />

If different fatty acids are esterified to the TAG—for example, the TAG with<br />

sn-1 palmitic acid, sn-2 oleic acid, <strong>and</strong> sn-3 stearic acid—the name replaces the -ic<br />

in the fatty acid name with -oyl, <strong>and</strong> fatty acids are named in sn1, sn2, sn3 order<br />

(1-palmitoyl-2-oleoyl-3-stearoyl-sn-glycerol). This TAG also can be named as sn-1palmito-2-oleo-3-stearin<br />

or sn-glycerol-1-palmitate-2-oleate-3-stearate. If two of the<br />

fatty acids are identical, the name incorporates the designation di- (e.g., 1,2-dipalmitoyl-3-oleoyl-sn-glycerol,<br />

1-stearoyl-2,3-dilinolenoyl-sn-glycerol, etc.).<br />

Figure 18 Mono <strong>and</strong> diacylglycerol structures.<br />

Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.

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