Lab Cat

14 Mar 2006

Vitamins Part 3: Food Additives

Filed under: Food, Science — Cat @ 4:46 pm

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.

General References

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

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3 Comments »

  1. I’ve really enjoyed your food chemistry posts, and this vitamin series thus far.

    I was wondering, though, do you have any opinion on so-called “whole food” or natural vitamins? This seems like a misnomer to me because a vitamin can’t possibly be whole food, it must be isolated or extracted, right? Assuming a vitamin can be extracted from whole food, wouldn’t the process damage it? Is it really any “better” than synthetic lab-created vitamins?

    Comment by Zetetic — 15 Mar 2006 @ 8:32 pm

  2. Zetetic – thanks for your comment and question.

    Natural vitamins are extracted from a natural source such as plants and artificial vitamins are synthesized in a lab. Extraction will destroy some of the vitamin as all processing does, but then it won’t be available as a vitamin and can’t be included on the label. This definition applies all food additives labeled natural or artificial.

    Natural and artificial vitamins won’t be any different from each other in terms of their chemistry as long as the artificial form used is the same isomer as the natural one. For example, vitamin C or L-ascorbic acid can be extracted from food sources or made by a chemical reaction from glucose. The active isomer of vitamin C is L ascorbic acid. D-ascorbic acid or erythorbic acid doesn’t have vitamin C activity, even though it still acts as an antioxidant in food.

    Whole food is an interesting misnomer. Whenever I see or hear that phrase I remember one of my nutrition profs lecture on whole food and asking if we would eat the whole of an orange – peel, pith and all. That is very few foods are eaten “whole”.

    My next post on vitamins will be on the legal aspects. Expect that to be up early next week sometime.

    Comment by Cat — 16 Mar 2006 @ 2:38 pm

  3. With concern over ascorbic acid and sodium benzoate in sodas creating benzene – I was wondering if ascorbyl palmitate can also react with sodium or potassium benzoate in the same way and create benzene?

    Comment by Connie Sanchez — 28 May 2006 @ 11:01 am


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