Food Lipids: Chemistry, Nutrition, and Biotechnology

1. Synthetic Approaches
Sucrose has eight hydroxyl groups that can be replaced or esterified with fatty acids.
The problem for chemists was how to bring two immiscible molecules (sucrose and
fatty acids or fatty acid methyl esters) to react in the presence of a suitable catalyst.
A logical approach would be to dissolve them in a mutual solvent. To obtain a
homogeneous solution of the reactants as required for synthesis of mono- and diesters
of sucrose, a transesterification reaction was set up: that is, sucrose and free fatty
acids were solubilized in mutual organic solvents such as dimethylformamide, dimethyl
sulfoxide, and dimethylpyrolidone. Sucrose fatty acid esters produced by this
Hass–Snell process were not approved for use in food because of the potentially
toxic solvents used (30,34). Later, Feuge et al. (36) described a solvent-free interesterification
between molten sucrose and fatty acid methyl esters at 170–187�C in
the presence of lithium, potassium, and sodium soaps as solubilizers and as catalysts.
In both processes, the unreacted FAME and free fatty acids are removed by distillation.
The higher the monoester content of the purified product, the better the SFEs
are as emulsifiers. Enzymatic synthesis of SFE has not been very successful. Both
buffer and organic solvent have been used to carry out enzymatic esterification of
sucrose with mixed results (37).
2. Emulsification Properties
Sucrose fatty acid esters were approved for use in Japan in 1959 and in the United
States in 1983 (34). Approved uses include:
1. As emulsifiers in baked goods and baking mixes, dairy product analogs,
frozen desserts and mixes, and whipping milk products.
2. As texturizers in biscuit mixes.
3. As components of protective coating for fresh apples, bananas, pears, pineapples,
avocados, plantains, limes, melons, papaya, peaches, and plums to
retard ripening and spoilage.
The properties of SFE and olestra depend in part on the degree of substitution
of sucrose with fatty acids, as shown in Table 4. SFE is used extensively in baked
goods to improve the finished quality of frozen bread dough and sugar snap cookies.
As a batter-aerating agent, SFE improves sponge and angel food cakes by increasing
cake volume by 10–20%. Other functional users of SFE are shown in Table 5. These
esters are seeing increased use in baked goods for several reasons:
1. They are easy to solubilize, can form good starch complexes, and can delay
or control starch granule gelatinization. They prevent sticking to machinery
and result in a softer crumb.
2. They are similar to the natural glycolipids found in wheat flour. Therefore,
they promote expansion of gluten, stabilize aerated bubbles in batter, and
make the manufacturing process easier.
3. They can inhibit crystal growth, such as ice crystals in frozen dough and
sugar crystals in sweet baked goods.
4. They can increase loaf and cake volume and tenderness. They increase
cookie spread factor and can affect crumb firmness and texture of sponge
cakes.
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