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Food Lipids: Chemistry, Nutrition, and Biotechnology

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28<br />

Structured <strong>Lipids</strong><br />

CASIMIR C. AKOH<br />

The University of Georgia, Athens, Georgia<br />

I. INTRODUCTION<br />

A. What Are Structured <strong>Lipids</strong>?<br />

In a broad sense, structured lipids (SLs) are triacylglycerols that have been modified<br />

by incorporation of new fatty acids, restructured to change the positions of fatty<br />

acids, or the fatty acid profile, from the natural state, or synthesized to yield novel<br />

triacylglycerols (TAGs). This definition includes the topics covered in Chapters 23,<br />

24, 25, <strong>and</strong> 30. The fatty acid profiles of conventional TAGs are genetically defined<br />

<strong>and</strong> unique to each plant or animal species. In this chapter, SLs are defined as TAGs<br />

containing mixtures of fatty acids (short chain <strong>and</strong>/or medium chain, plus long chain)<br />

esterified to the glycerol moiety, preferably in the same glycerol molecule. Figure 1<br />

shows the general structure of SLs; their potency increases if each glycerol moiety<br />

contains both short <strong>and</strong>/or medium chain <strong>and</strong> long chain fatty acids. SLs combine<br />

the unique characteristics of component fatty acids such as melting behavior, digestion,<br />

absorption, <strong>and</strong> metabolism to enhance their use in foods, nutrition, <strong>and</strong> therapeutics.<br />

Individuals unable to metabolize certain dietary fats or with pancreatic insufficiency<br />

may benefit from the consumption of SL.<br />

Structured lipids are often referred to as a new generation of fats that can be<br />

considered as ‘‘nutraceuticals’’: food or parts of food that provide medical or health<br />

benefits, including the potential for the prevention <strong>and</strong>/or treatment of disease (1).<br />

Sometimes, they are referred to as functional foods or in the present context, as<br />

functional lipids. ‘‘Functional foods’’ is a term used to broadly describe foods that<br />

provide specific health benefits. Medical foods (medical lipids) are foods (lipids)<br />

developed for use under medical supervision to treat or manage particular disease or<br />

nutritional deficiency states. Other terms used to describe functional foods are phys-<br />

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

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