ABSTRACT
I. INTRODUCTION A. What Are Structured Lipids? In a broad sense, structured lipids (SLs) are triacylglycerols that have been modified by incorporation of new fatty acids, restructured to change the positions of fatty acids, or the fatty acid profile, from the natural state, or synthesized to yield novel triacylglycerols (TAGs). This definition includes the topics covered in Chapters 23, 24, 25, and 30. The fatty acid profiles of conventional TAGs are genetically defined and unique to each plant or animal species. In this chapter, SLs are defined as TAGs containing mixtures of fatty acids (short chain and/or medium chain, plus long chain) esterified to the glycerol moiety, preferably in the same glycerol molecule. Figure 1 shows the general structure of SLs; their potency increases if each glycerol moiety contains both short and/or medium chain and long chain fatty acids. SLs combine the unique characteristics of component fatty acids such as melting behavior, digestion, absorption, and metabolism to enhance their use in foods, nutrition, and therapeutics. Individuals unable to metabolize certain dietary fats or with pancreatic insufficiency may benefit from the consumption of SL.
