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Food Lipids: Chemistry, Nutrition, and Biotechnology

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Table 6 Comparison of General Properties of Fat Replacers<br />

Property Protein-based Carbohydrate-based Lipid-based<br />

Physical form Powder Powder/liquid Powder, solid, liquid<br />

Taste a<br />

Bl<strong>and</strong> Bl<strong>and</strong> Bl<strong>and</strong><br />

Caloric value, kcal/g 1–4 1–4.5 0–8.3<br />

Melting point, �C b<br />

Variable Variable Range variable depending on<br />

fatty acid, unsaturation,<br />

<strong>and</strong> degree of substitution<br />

Color White White Yellow to golden yellow<br />

Odor None None None<br />

Soluble at 25�C in: Water Water, insoluble Hexane, vegetable oils<br />

Viscosity Variable Variable Olestra more viscous than<br />

vegetable oils<br />

Oxidative stability Stable Stable Oil type of olestra not very<br />

stable; medium chain<br />

length triglycerides very<br />

stable<br />

Stability to frying<br />

temperature<br />

Not stable Not stable Most are stable<br />

a<br />

Bl<strong>and</strong> is a general term applicable to most but not all fat replacers.<br />

b<br />

Variable melting point; depends on the specific compound. Actual values may be obtained from the<br />

supplier.<br />

melting behavior of carbohydrate polyesters, such as sucrose <strong>and</strong> raffinose polyesters,<br />

has been reported (2,14,45). The melting points decreases with an increase in unsaturation<br />

of fatty acids. Carbohydrate or alkyl glycoside polyester with a desirable<br />

melting point range <strong>and</strong> other physical properties are prepared by blending fatty acid<br />

methyl esters of various degrees of saturation <strong>and</strong> unsaturation prior to synthesis of<br />

the saccharide polyester (14).<br />

Lipid-based fat substitutes are subject to oxidation just like conventional triacylglycerols.<br />

The addition of the antioxidant TBHQ was reported to greatly improve<br />

the stability of liquid carbohydrate fatty acid polyester fat substitutes <strong>and</strong> vegetable<br />

oils. The degree of added stability was greater in the fat substitutes <strong>and</strong> in the refined,<br />

bleached, <strong>and</strong> deodorized (RBD) soybean oil than in the crude soybean oil (46). Part<br />

of the explanation was that RBD oils <strong>and</strong> fat substitutes made with them have lost<br />

some of the protective natural tocopherols, which must be restored to improve storage<br />

stability.<br />

V. METABOLISM OF LIPID-BASED FAT SUBSTITUTES<br />

Lipid-based fat substitutes, as exemplified by sucrose, trehalose, sorbitol, raffinose,<br />

stachyose, <strong>and</strong> sorbestrin, are not hydrolyzed by pancreatic lipase <strong>and</strong> consequently<br />

are not taken up by the intestinal mucosa (7,11,20,47). However, alkyl glycoside<br />

fatty acid polyesters may be partially hydrolyzed <strong>and</strong> absorbed (19). Mattson <strong>and</strong><br />

Volpenhein (48) reported that as the number of ester groups increased from 4 to 8<br />

in sucrose polyester, the rate of hydrolysis by lipase decreased. In other words,<br />

digestibility <strong>and</strong> absorbability of carbohydrate polyesters in rats <strong>and</strong> humans are<br />

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

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