Biomedical Engineering Reference
In-Depth Information
The use of lecithin fractions as liposomes in foods is relatively new. By frac-
tionating the complex mixture of lecithin and removing part of the phospholipids it
is possible to optimize these special functions. These are discussed here.
W ATER R ETENTION
This is important for maintaining the freshness of baked goods. If a “liposome cream”
is made, some great portion of the water will be firmly bound in the finished bread,
which will take considerable time to release thereby enhancing bread freshness.
F LAVOR R ETENTION
Liposome formation can increase substantially the surface area of the product result-
ing in enhanced flavor. For example, the subjective freshness of a cake is greatly
enhanced by the fine fat distribution brought about by the liposomes.
P ROTECTIONAGAINST I NACTIVATION
Yeast cells in frozen dough are exposed to very considerable stresses. Some of these
yeast cells are inactivated by ice crystals and the processes related to the cold. In
the past, attempts were made to circumvent this problem by just adding more yeast.
However, by using liposomesit is possible to provide the yeast with sufficient
protection against cold. The membranes of yeast have a high content of unsaturated
fatty acids so that they remain fluid and not inactivated or destroyed by crystalliza-
tion. When the temperature of the dough rises again, they are ready for action
immediately so that baking yields improve significantly.
Liposomes can also be loaded with water-insoluble (fat-soluble) matter including
vitamins and flavorings.Flavorings encapsulated in liposomes do not diffuse through
the membrane until they are needed. 82 The food applications of liposomes are
summarized in Table 7.6 .
TABLE 7.6
Some Food Applications of Liposomes
Function
Food
Control of crystallization
Extruded snacks
Lowering of the freezing point
Convenience products
Protection against surrounding influences
Cakes and pastry goods
Separation of aqueous/fat phases
Bread and biscuits
Flavor retention
Ice cream
Water retention, control of a w value
Cheese
Sensory impressions substitute for fat
Frozen dough portions and pizza
Enzyme functionality
Protection of yeast cells against cold
 
 
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