Emulsifiers alter fat functionalities.
Many alternatives are being offered to food processors today to reduce fats in food formulations. Most of them are substitute ingredients for the fat and oil normally present. They may be derived from various proteins, carbohydrates, or other sources that reduce the calories added, yet can be modified or processed to provide the textural attributes of fat globules. Some can achieve the smooth, rich mouthfeel of fat, but often fail to replace the desirable flavor notes of fat components or other functional properties.
Another approach involves utilizing the properties and attributes of various functional fat systems available, together with the optimized application of the extensive emulsifier technology already known for formulating foods.
Most existing food products have not been formulated with optimization of fat functionality in mind. Therefore, optimization of fat functionalities can result in fat reductions with little or no loss of quality. Similarly, the optimum functionality of the fat system may be dependent on its dispersion in foods. For example, fat globule size is important to lubricity and richness of the food. Addition of an emulsifier can result in smaller fat globules with increased surface activity and reduced fat content without loss of lubricity.
Optimum functionality relates also to fat or oil selection. If only lubricity is required, a liquid oil ma be better than a solid fat. Altering the fatty acid profile or adding an antioxidant to the oil may solve any problems of oxidative rancidity or emulsification of the oil may enhance the lubricity effect. A carefully selected hard fat is required for structural properties in designing a product's overall fat system.
Another fat system that can be optimized to reduce fat content is through the addition of mono- or diglyceride emulsifiers to cake shortenings. Still further reduction is possible by suspending emulsifiers in liquid oil (e.g., fluid shortenings) for better dispersion in cake batters.
Understanding the functionality of fats and emulsifiers in order to reduce fat levels in foods can also offer guidelines in application. For example, emulsifiers used in full-fat products will require modification for optimal performance in a low-fat product. And, combinations of emulsifiers usually offer superior performance. Dry blending of powdered emulsifiers is less desirable, as crystalline emulsifiers do not offer maximum functionality.
Not only is fat selection for functionality important, but the choice of an emulsifier system and its functionalities is critical. Emulsifiers are compounds containing both hydrophilic and lipophilic fractions. This allows them to migrate to the interface between immiscible substances and form a stable film.
The hydrophilic/lipophilic balance (HLB) is a numerical value that is given to every emulsifier to predict water solubility and emulsion activity (i.e., water-in-oil or oil-in-water) in simple systems. However, other components of food systems--like proteins--can alter ingredient interactions.
An HLB scale is a guide, but of limited use in most food systems. It is much more important to select an emulsifier based on the functionality required of it in a specific food system (e.g., aeration, dough conditioning). Emulsifier suppliers know very specifically what functions are provided by each different emulsifier in each different food category. For example, they control viscosity in chocolate and coatings, provide freeze-thaw stability in frozen desserts, serve as a plasticizer in chewing gum, or prevent oil separation in peanut butter. Select emulsifier systems according to the functions needed.
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|Author:||Duxbury, Dean D.|
|Date:||May 1, 1992|
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