In this article, I will discuss and analyze the group of ingredients called emulsifiers and how they affect the kashruth of the products in which they are used.
The basic definition of an emulsifier is a product which allows two substances to mix homogeneously which ordinarily would not have mixed well. Soap, though not a food, is a common example of an emulsifier. When one's hands are greasy or oily, the use of water alone - even hot water - is to no avail. This is because oil and water just do not mix together and thus, the oily coating is absolutely impervious to the water. However, when soap is added the oil layer dissolves in the water and is easily washed away. This phenomenon is the underlying principle of the widespread spectrum of products called emulsifiers.
One of the most common examples of emulsified food product is mayonnaise. This product is basically a mixture of oil and water with other ingredients added for taste and texture. Every emulsified mixture contains at least two components or "phases" which ordinarily do not mix well together. In mayonnaise, these two phases are oil and water. Margarine, another emulsified product, is also a combination of an oil phase and a water phase. The presence of an emulsifier allows these two components to form a stable and homogeneous product.
Chemically, the molecular structure of an emulsifier gives us a clue to the way it functions. An emulsifier consists of a "chain" of molecules. One end of this chain is "hydrophilic" which means it has an affinity for water. The other end of the chain is "lipophilic" meaning it has an affinity for oil. The position of this "chain" at the point of contact between the oil and water phases locks them together creating a unified entity.
There are several types of emulsifiers used by the food industry. The simplest type is a natural emulsifier derived from a vegetable source called lecithin. Although derivable form a wide variety of source, this natural emulsifier is commonly derived form soybeans. The soy oil expressed from the soil beans is treated with steam in order to produce the lecithin which is commonly used as an emulsifier in chocolate bars and chocolate candy. The presence of lecithin allows the various ingredients used in chocolate to maintain stability and prevent separation and spoilage.
Many kosher consumers are keenly aware of certain "red flag" ingredients which may appear on the ingredient panel of various foods. One of these - "mono and diglycerides" - is a typical emulsifier used extensively in the food industry. From a kashruth point of view, this is a highly sensitive item and requires supervision. The two raw materials which form the basis of mono and diglycerides are glycerin and a fatty acid. As its name suggests, fatty acids are substances which are chemically derived from a fat source which can be either vegetable or animal. The two most prevalent fatty acids used in the manufacture of mono and diglycerides are oleic acid and stearic acid. These acids are derived from either beef fat, coconut oil, palm oil, or palm kernel oil. The kosher status of glycerin is also critical. Glycerin can be derived from three basic sources: Animal fat, petroleum, or vegetable oil. Ascertaining that these raw materials are vegetable derived ingredients in origin is only half the battle. There are many companies, both here and abroad, that produce both vegetable and animal material on the very same equipment. Even the vegetable derived ingredient is unacceptable if it is produced on non-kosher equipment. The OU makes arrangements with these companies to supervise cleaning and koshering of the equipment and the subsequent production. Only then is the OU emblem affixed to each container of a product. Only optimal supervision can guarantee that these ingredients come from approves sources. The presence of mono and diglycerides in a food item signals the consumer that kosher supervision is definitely required.
There are many other types of emulsifiers and many of them are variations of mono and diglycerides. Various additives are used to create emulsifiers which have unique functions critical to certain types of foods. Thus, "ethoxylated mono and diglycerides," "lactylated mono and diglycerides," "sodium stearoyl lactylate," and "polyglycerol esters of fatty acids" are terms that wrinkle the brow of kosher consumers and require optimal kashruth control.
The practical applications of food-grade emulsifiers are quite numerous. Generally speaking, food companies use an "orchestra" of ingredients in any given food product. There are serious concerns that the various components not affect each other detrimentally. The presence of an emulsifier system puts a "conductor" at the head of the "orchestra" and insures all components work together harmoniously. I will briefly discuss usages of emulsifiers which are most prevalent in food technology today.
Manufactures of baked goods are concerned with preventing their products from becoming stale. Stale baked goods are a result of a chemical change called "crystallization" which takes place in starch. Soft pockets of starch change to brittle crystals which cause hardening of the product and formation of crumbs. In order to retard staling, emulsifiers are added which chemically combine with the starch in order to prevent this crystallization from taking place and thus retain the freshness and softness of the baked goods for a longer period of time.
Not all emulsions are of the oil-water type. Many products in the marketplace today are solutions of gas in liquid. Common examples of this are aerosol products such as whipped cream and non-stick sprays. Emulsifiers are added to these products to insure the stability of the aerated or foam products.
Have you ever tried to dissolve pure cocoa powder in cold milk? The attempt is usually met with frustration since the cocoa particles clump together and actually remain dry and not affected by the milk. There are several chocolate powders on the market, however, which dissolve easily in cold milk. This change is due to the addition of an emulsifier which acts as a "wetting agent" for the powder. As its name suggests, it allows the powder to mix with the milk thus enabling it to dissolve. By reducing the surface tension between liquid and solid phases, a stable solution results.
Another important aim of emulsifiers is improvement of palatability. There are many products such as chocolate coatings and icings which utilize fats or fatty ingredients. These products require the presence of fat in order to maintain their consistency and texture. The drawback of the presence of these fats is the "mouthfeel" which they impart to the final product. A greasy or pastelike aftertaste is hardly what a company wants when positive consumer response is critical to the "bottom line." The addition of emulsifiers makes the finished product more palatable since it reduces the greasy aftertaste of the fat component. Thus, texture and stability does not compromise taste and consumer acceptability.
Emulsifiers are a major ingredient group used in products throughout the food industry. I have endeavored to demonstrate the importance and function of these materials and at the same time illustrate the kashruth concerns regarding them. As in all areas of the food industry this area is constantly changing. The OU, through research and study, keeps up with these developments so that standards of kosher certification are always maintained.
Rabbi Moshe Bernstein is Administrative Rabbinic Coordinator of the Orthodox Union's Kashruth Division