Emulsifiers
Pages 47-66
DOI: https://doi.org/10.1094/1891127020.004
ISBN: 1-891127-02-0
Abstract
Topics Covered
- Antistaling Agents
- Starch Gelatinization
- Starch Retrogration
- Bread Staling
- Emulsifier-Starch Complexation
- Dough Stengtheners
- Aeration Agents
- Troubleshooting
Introduction to Chapter
Surfactants used in the production of bakery goods are usually referred to as either “emulsifiers” or “dough strengtheners.” From a physical chemist's point of view, the way these terms are used is imprecise. The interfacial role of these materials is spelled out in this section, but in the remainder of this chapter, current bakery terminology is used for the sake of convenience.
Strictly speaking, an emulsifier is a surfactant that promotes the formation of an emulsion; that is, it aids in the subdivision of particles of the discontinuous phase. In bakery usage, this function is most important in the production of batters for cake, cake doughnuts, waffles, etc.
The term “emulsifier” is also applied to compounds (i.e., crumb softeners) that interact with molecules and granules of gelatinized starch and slow the rate at which they recrystallize, thereby contributing to the retention of crumb softness. Surfactants that perform this role react at the solid-liquid, not the liquid-liquid, interface.
Dough strengtheners are surfactants that presumably interact with gluten proteins and enhance the dough characteristics that bakers call “strength.” Again, the functionality is at the solid-liquid interface.
All bakery surfactants aid the incorporation and subdivision of air into the liquid phase; that is, they promote foam formation. This is important in cake production and in the generation of fine-grained crumb in bread. Compounds used for this purpose are usually called emulsifiers, although they are actually foaming agents that function at the gas-liquid interface.
Finally, it should be noted that any given surfactant may function in all the ways listed, even though it is used primarily for one specific function. For example, sodium stearoyl lactylate (SSL) is used mainly for its dough-strengthening effect, but it also promotes emulsification, air incorporation and subdivision, and retention of crumb softness. Again, in the viewpoint of the physical chemist, a bakery dough or batter is a “messy” system with a multitude of interfacial interactions occurring simultaneously. It is helpful to isolate each type of interaction for discussion, realizing that ultimately all functions must be considered together to realistically assess the effects of surfactants on bakery foods.
