Food Additives

Food Colour and Colour Additives

The presence of colour in food is a highly motivating force on our eating habits. Just look at the picture above and decide which grape or piece of pineapple you want to eat!.

Joint FAO/WHO Expert Committee on Food Additives (JECFA)

The JECFA has been in existence since 1955 and serves as a scientific advisory committee to FAO, WHO, Member Governments and the Codex Alimentarius Commission. Its principal role is to assess the human health risks associated with the consumption of additives to food and to recommend Acceptable Daily Intake (ADI) levels, tolerable limits for environmental and industrial chemical contaminants in food and Maximum Residue Levels (MRL) of agricultural chemical inputs in food such as veterinary drug residues in meat and meat products.

Colouring matter as food additives

Prior to the discovery of synthetic dyes by Perkins in 1856, only natural dyestuffs were added to foods. During the early part of the twentieth century a large number of cheap dyes were synthesised and many of these then found their way into food products.
Once countries began to legislate what could be added to food the number of both natural and synthetic colours used in food dropped markedly.
The situation today is that countries differ in what they consider to be safe and the same dyes are not necessarily used world-wide. In the case of Norway, the use of any synthetic colour additives has been forbidden since 1976.
The situation becomes even more confusing when natural dyes are synthesised i.e the nature-identical dyes.

A table showing dyes commonly used as food additives in a number of different countries are given with their E, CI and FD&C codes. The E (EEC code) is being replaced for international use by the Codex Alimentarius Commission who are developing an International Numbering System (INS). This will largely use the same numbers (but without the E). CI is the code used in the Colour Index Volumes.

In the USA, the Food and Drug Administration (FDA) is responsible for regulating colour additives and they use codes beginning with FD&C (from the Federal Food, Drug and Cosmetic Act of 1938).

Tartrazine (CI 19140) for example, is referred to as E102 in the UK, has an INS number of 102 but in the USA is generally referred to as FD&C Yellow No. 5. The JECFA has set its Acceptable Daily Intake (ADI) value as 0 - 7.5 mg per kilogram of body weight.

Softdrinks

A number of synthetic dyestuffs are commonly found in soft drinks, for example Kool Aid. For a list of Kool Aid FAQ which gives the history and describes the flavours available, check the site in Holland for links.

Vis Spectra of "grape" softdrinks

For comparison, some pure grape juice was recorded and is shown by trace 1. Trace 2 corresponds to Kool-Aid "GRAPE BERRY SPLASH" TM which contains INS 129 and INS 133. The other two spectra are local soft drinks that contain INS 123 and INS 133.

These powdered drinks are a convenient source of colouring material for simple spectrophotometric exercises. The colours found in packet drinks from a local supermarket include:

allura red	INS 129	ADI 0 - 7	JECFA 25/18
amaranth	INS 123	ADI 0 - 0.5	JECFA 25/16
brilliant blue	INS 133	ADI 0 - 12.5	JECFA 13/12
fast green FCF	INS 143	ADI 0 - 25	JECFA 30/24
sunset yellow	INS 110	ADI 0 - 2.5	JECFA 26/24
and tartrazine	INS 102	ADI 0 - 7.5	JECFA 8/14.

Values taken from the Summary of Evaluation performed by the Joint FAO/WHO Expert Committee on Food Additives 1956-1993 (1st -41st meetings). The references refer to meeting number / page number.
For example, the KOOL-AID products "MAN-O-MANGO BERRY" TM and "SHARKLEBERRY FIN" TM are both listed with FD&C red #40 (ie allura red). Locally produced GRACE "QUENCH AID" has a drink mix called "STRAWBERRY RACERS" which contains FD&C red #2 (this refers to amaranth, banned in the USA since 1976, but used in Europe as INS 123).
A look at the values above shows the Acceptable Daily Intakes (ADI) as 0 - 7 and 0 - 0.5 mg/kg body weight respectively.

Problem

Determine, or look up, the molar absorbances (extinction coefficients) for these dyestuffs.
Hint. These are sometimes quoted as absorbance for 1% solutions.
Calculate the amount of dyestuff in a packet of drink mix.
Calculate how many drinks (packets) you would need to exceed the ADI.
Email me the answer for your favourite flavour.

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Created and maintained by Prof. Robert J. Lancashire,
The Department of Chemistry, University of the West Indies,
Mona Campus, Kingston 7, Jamaica.

Created April 1997. Links checked and/or last modified 10th April 2015.
URL http://wwwchem.uwimona.edu.jm/lectures/foodcol.html