All right, let's try this again.
A food additive is a substance that is intentionally added to a food for a wide variety of reasons. The United States Food and Drug Administration (FDA) classifies food additives according to the purpose for which they are added, which are:
- to maintain or improve nutritional quality
- to maintain quality and freshness
- to aid in the processing and preparation of food
- to make food more appealing
For these seemingly simple tasks, the FDA allows some 2,800 substances to be added to foods. (Lots more inadvertantly find their way in during processing and packaging, but these aren't considered food additives because they aren't added intentionally.) To get an additive added to the list can take years and many tests involving animals, which are subjected to these substances to find out if they cause cancer or birth defects. Poor animals.
Two categories of food are exempted from this process: 700 substances known as GRAS ("generally recognized as safe") because of extensive past use with no ill effects; and substances approved before 1958. However, many of these are being tested to be sure they really are safe for consumption.
Apparently 98% by weight of all food additives used in the US are either baking soda, citric acid, corn syrup, musard, pepper, salt, sugar, and vegetable colouring. Other common additives are listed below.
- Nutrients are added to maintain or improve nutritional quality; they may enrich or replace vitamins and minerals that are lost in processing, or fortify to add nutrients that are lacking. Common nutrients added to foods are beta carotene, vitamin A, vitamin D, vitamin E, niacinamide, and riboflavin.
- Preservatives are added to a food to prevent spoilage from bacteria, mold, fungus, or yeast; to extend a product's shelf life; and to "protect" colour and flavour. Common preservatives are benzoic acid, BHA or butylated hydroxyanisole, BHT or butylated hydroxytoluene, butylparaben, calcium propionate, EDTA or ethylene-diaminetetra-acetic acid, heptylparaben, lactic acid, methylparaben, potassium propionate, sodium benzoate, sodium nitrate, sodium propionate, TBHQ or tertiary butyl hydroquinone, vitamin C, and vitamin E. The ones with acronyms, like BHT, as well as the vitamins, act as antioxidants, a preservative function.
- A number of additives make food processing or preparation easier:
Then there are the substances added for cosmetic or taste purposes, to make food more appealing to the consumer:
- Emulsifiers are added to help two liquids to emulsify, promoting homogeneity, consistency, stability, or texture. These include diglycerides, polysorbates, and sorbitan monostearate.
- Stabilizers and thickening texturizers impart body, improve constistency, stabilize emulsions, and improve mouth feel. They include arabingalactan, carob bean gum, cellulose, guar gum, gum arabic, mannitol, modified food starch, propylene glycol, and tragacanth gum.
- Leavening agents affect the texture and volume of cooked foods, promoting light airy products. Calcium phosphate is a leavening agent.
- pH control agents are added to change or maintain acidity or alkalinity, and include acetic acid, ammonium alginate, lactic acid, phosphoric acid, sodium citrate, and tartaric acid.
- Humectants make a product retain moisture; examples here are glycerine and propylene glycol.
- The awkwardly named maturing and bleaching agents and dough conditioners are added to baked goods to accelerate yeast maturity and improve baking qualities. Here we have things you don't usually associate with food, like acetone peroxide, calcium bromate, hydrogen peroxide, potassium bromate, and sodium stearyl fumarate.
- Anti-caking agents, as their name suggests, prevent powdered substances from lumping or caking together. Among them, iron-ammonium citrate and mannitol.
- Flavour enhancers to supplement, magnify, or modify the taste and/or aroma of food without adding one of their own. Disodium guanylate is the only one on the list I'm working from, but I'd think monosodium glutamate would belong here.
- Flavours are added to "heighten" natural flavours which might have been lost in processing; vanilla is the sole one on my list here, though the category "natural and artificial flavours" figures prominently on the labels of most processed food.
- Colours make things look desirable, appetizing, or characteristic of the real thing; lots of additives here, including annatto extract, beta carotene, canthaxanthin, dried algae meal (yum!), Blue No. 1, Red No. 2, Red No. 40, Yellow No. 5, grape-skin extract, iron oxide, riboflavin, saffron, tagetes, titanium dioxide, and ultramarine blue.
- Sweeteners. I guess you know what they do. They include dextrose, fructose, invert sugar, mannitol, and xylitol. Just think of them as sugar.
My primary source for this node was my Food Lover's Companion, and the scariest thing about the list here, I think, is how many of these names I recognize. There is another, even longer list at the FDA website, http://vm.cfsan.fda.gov/~dms/eafus.html, but even that one, it seems, doesn't list all the possible additives that are allowed by US law.