Food additives are chemical compounds, other than the basic food components, that are added during processing of food to preserve flavor, improve its taste and appearance. Legally they are defined as “any substance the intended use of which results or may reasonably be expected to result — directly or indirectly — in its becoming a component or otherwise affecting the characteristics of any food?. This includes any substance that is present in food as a result of any aspect of production, processing, storage or packaging. Everything added to food in the US can be found here. In the US, food additives do not include pesticides or color additives.
In the European Union, approved food additives are given E-numbers. This has a mixed response as some people will food with E-numbers, but will eat food that has the chemical name(s) in the ingredient list.
Beta carotene and riboflavin are approved color additives to foods generally added as natural pigments. Beta carotene gives an orange-yellow color and is mainly added to margarine and butter and is are converted to Vitamin A in the liver. Annatto is considered to be a carotenoid as its main component is bixin. It is added to cheese, ice cream, other dairy products, margarine, oils to make them orange. Riboflavin gives an yellow orange color. It can be found in baby foods, breakfast cereals, sauces, processed cheese, fruit drinks. In excess, riboflavin is excreted in the urine turning it bright yellow. Now you know where that color comes from after having a multi-vitamin.
Alpha tocopherol is added as an antioxidant. An antioxidant is a chemical that halts the oxidation of other chemicals. It is well known that vitamin E has a biological function as an antioxidant (bio-antioxidant role), but it is also use to prevent oxidation in lipid based foods such as vegetable oils (reference: Huang, S.W. J. Agric. Food Chem. 43, 2345-2350, 1995.), where the addition of tocopherol and derivatives slow down rancidity.
Ascorbic acid is added as an food additive because of its antioxidative and reducing properties. In addition to acting as an antioxidant, ascorbic acid is added as a dough improver, to prevent enzymatic browning, , to reduce of metal ions, to protect oxidizable compounds, such as folates, and to regenerate other antioxidants especially tocopherols (reference: Beddows, C.G. Food Chemistry, 73, 255-261. 2001). In cured meat ascorbic acid acts with nitrite to inhibit the growth the Clostridium botulinum, at the same time inhibiting nitrosamine formation. Due to its reducing power, ascorbic acid is sometimes added to ground beef to convert metmyoglobin to myoglobin and oxymyoglobin. This helps to keep the ground meat red.
Vitamin C is added as either the acid or in the ascorbate form. Also ascorbyl palmitate and stearate are used as a fat soluble form to prevent lipid oxidation and to allow vitamin E regeneration. Ascorbyl palmitate is biologically active as implied by this site and this article (M. Pokorski, B. Gonet, Physiol. Res. 53: 311-315, 2004), which suggests it may even have advantages over the water soluble form, ascorbic acid.
More controversially, when ascorbic acid and sodium benzoate are added to beverages at the same time, it appears that the reaction results in benzene. There is concern as the levels of benzene found in soft drinks are higher than that allowed by federal standards for water.
Thiamin, riboflavin, folic acid, niacin are added to flour to make enriched flour. But that is the topic for Part 4: Vitamins and Government Regulations.
Fennema, O. Food Chemistry, (3rd edition); Marcel Dekker, 1997.
Christen G.L. and Smith, J.S. Food Chemistry: Principles and Applications, Science Technology System 2000
Branen, A.L., Davidson, P.M., Salminen, S. Thorngate (III), J.H (Eds) Food Additives (Second Edition); Marcel Dekker, 2002