Industrial Chemistry: For Advanced Students - Mark A. Benvenuto 2015

Food additives

Any material intentionally put into food can be considered as food additive. Perhaps the oldest in history is the addition of salt, NaCl, which was used both to enhance flavor and to preserve foods for long periods of time when no form of artificial refrigeration was known, although vinegar may be a competitor for the title of “oldest.” There are a few broad purposes for any food additive, such as enhancing color, flavor, or what is called “mouth feel.” Also, additives to food are often used to preserve freshness and extend a product’s shelf life.

11.1 Categorizing food additives: organic and inorganic

Food additives can be categorized in numerous ways and placed in several different subgroups. Since we wish to focus on the chemistry that goes into producing them, we begin by breaking this large field down into the broad categories of organic or inorganic materials. We will begin with several subdivisions of organic additives: food colorings, flavor enhancers, preservatives, and those that enhance mouth feel. This will be followed by a series of inorganic additives.

11.1.1 Food coloring

A wide variety of food colorings have been developed, which the United States Food and Drug Administration considers acceptable for human consumption. The term, “generally regarded as safe,” (GRAS) applies to these substances.

As an example of food coloring use, Figure 11.1 shows the ingredients list from “Dippin’ Dots Rainbow Ice Artificially Flavored Ice” which includes four different food colorings. While these are considered ingredients, they are specifically added to the material only to produce colors that are pleasing to the eye — so that consumers will purchase the item. Indeed, this is the purpose of many food colors — to make the food appear more palatable, or to give it a color the consumer expects or wants. Without such additives, many food items would not be as colorful as they are now, and would be perceived as less tasty. Other common examples are the famous M&Ms^® and Skittles^®.

Several food colors are currently in use in North America, the European Union, and other parts of the world. Others have been used, but are currently banned because of some safety and human health concern. Additionally, several colors have been developed and brought to large-scale production because they can be considered natural, and thus are perceived as being safer than colors that were those produced synthetically. Table 11.1 shows current food colors.

Fig. 11.1: Ingredients list from an ice cream product.

Table 11.1: Food colors in use (Food and Drug Administration, 2014).

Table 11.2: Natural food colorings.

What are called natural food colors are also regulated by the national government, since they are intended for human ingestion (Food and Drug Administration, 2014; Food Additives and Ingredients Association, 2014). A list of natural food colors is given in Table 11.2, although they are probably smaller, niche use food colors that are not listed here.

While colorings can be specific to foods, there are also several that can be used in other applications, which have been approved for use by the FDA (Food and Drug Administration, 2014). Saffron, mentioned in Table 11.2, is an example of a material that is also used in clothing dyes to impart a color that does not fade.

11.1.2 Flavor enhancers

By far, the oldest established flavor enhancers are salt and vinegar, known from ancient times. Perhaps this is followed historically by pepper and the other spices that came from Asia to Europe across the long land and sea trade routes during the Middle Ages. Indeed, this quest for rare and aromatic spices was one of the reasons a Genoese sailor at that time, Christobal Colon, was able to get royal endorsement to sail West from Europe to find the lands where these rare spices were produced. Now we know this man by his more anglicized name, Christopher Columbus.

Now, however, there are a variety of food additives recognized in the United States and Europe that qualify as flavor enhancers. Table 11.3 shows several of the more common flavor enhancers which are considered GRAS materials. There are others as well.

Table 11.3: Flavor enhancers.

It is notable that several of these structures are esters or aldehydes. Such molecules are often known for their pleasant fragrances (and sometimes unpleasant ones!). The large-scale synthesis of several of these materials now starts routinely with small organic molecules that have been separated from some fraction of crude oil. Examples of this are cinnamic aldehyde as shown in Figure 11.2 and wintergreen oil shown in Figure 11.3.

Fig. 11.2: Synthesis of cinnamic aldehyde.

Fig. 11.3: Synthesis of wintergreen oil.

As can be seen from the starting materials in each of the above cases, the ultimate source for these two flavor enhancers is petroleum based, which means it will be abundantly available as long as petroleum is inexpensive.

11.1.3 Preserving freshness

As with flavor enhancers, salt qualifies as one of the oldest food additives that have been used to preserve the freshness of foods. Since the Second World War, a number of additives have been discovered, and their production has been scaled up to industrial levels, which enable foods to be kept fresh for extended periods of time. This enables those foods to be transported long distances without spoilage. Table 11.4 lists the most common food preservatives.

Table 11.4: Common preservative food additives.

Table 11.5: Food additives that enhance mouth feel.

11.1.4 Enhancing mouth feel

The term “mouth feel” is rather self-explanatory. It is some material or substance that is designed to make an edible item feel more pleasant or agreeable while it is being consumed. There are many additives that serve this purpose. Once again, they must meet the safety requirements so that they can be considered as GRAS before they can be placed in products sold to the public. Some of the most common are listed in Table 11.5. These additives and several others are extracted from numerous plant sources. Often, when a product is sold as low calorie, some components are removed to lessen the total calorie count, and must be replaced to maintain the product’s volume. Additives that do this and enhance the mouth feel of the finished product thus, serve a dual purpose.

There is sometimes controversy when a synthetic mouth feel additive is incorporated into a food, as the idea of a synthetic additive appears to members of the general public to be unhealthy, or unnatural. In 2011, the addition of phthalates to some Taiwanese sports drinks raised concerns about the resultant health effects of consuming them (Self and Qu, 2012).

11.1.5 Inorganic additives

Numerous inorganic materials also find uses as food additives. While we have listed common table salt in several of the above tables, there are several other inorganic materials which are added to foods. One can debate that some of these also qualify as organic, such as ammonium acetate, because while the ammonium may be inorganic, the acetate is an anion of an organic acid. Our listing in Table 11.6 shows several of the more commonly used materials, which have at least one inorganic component.

Table 11.6: Inorganic food additives.

11.2 Production

The methods by which food additives are produced on a large scale are more numerous than the number of additives themselves, as some have multiple production methods. For example, sodium chloride can be mined or reclaimed from ocean waters through evaporation of large and shallow pools.

Many organic materials, for example BHA and BHT, ultimately have oil as the source material. The production of BHT is shown in Figure 11.4 as an example, showing toluene as its starting material.

Fig. 11.4: BHT production.

Several inorganic materials that are used as food additives are produced from mining and refining a mineral source.

11.3 Recycling

Virtually none of the materials listed in this chapter are recycled. All are designed to be the part of one food product or another, and thus, they are consumed.

Bibliography

Association of Flavor Chemists. Website. (Accessed 24 May 2014, as: http://flavorchemists.com/).

European Commission, Health and Consumers, Food. Website. (Accessed 2 September 2014, as: http://ec.europa.eu/food/food/fAEF/additives/index_en.htm).

Food Additives and Ingredients Association. Website. (Accessed 24 May 2014, as: http://www.faia.org.uk/).

Food and Drug Administration. Website. (Accessed 1 February 2014, as: http://www.fda.gov/ForIndustry/ColorAdditives/ColorAdditiveInventories/ucm115641.htm).

International Food Additives Council. Website. (Accessed 24 May, 2014, as: http://www.foodadditives.org).

Self, R. L.; Wu, W-H. Rapid qualitative analysis of phthalates added to food and nutraceutical products by direct analysis in real time/orbitrap mass spectrometry. Food Control, 25 (2012) 13—16.