The Chemistry Of Food Colourings

By Muhammad Salman Chukkan and Anusha Mishra*

Would you drink black water? Clear Pepsi? These are Food fads; it was out of popularity due to Consumer Unacceptance. The major reason for this was that consumer links flavour with certain colours. Food colours are not meant for nutrition, it is added to the food to match the consumer expectations, or to add the colour which is lost during processing, transportation and storage. The link between color and taste is logical. Since oranges are orange, we expect orange-colored barfi to be orange-flavored. Red drinks should taste like pomegranate, and purple drinks should taste like grapes. If food is multi-coloured, the consumers don’t usually prefer to have the same, unless you are eating some exotic dishes like blue cheese which gets its distinct flavor from mold! The Demand for colour was increased when the market was introduced with shelf-stable foods or increased shelf-life foods.

According to FSSAI, Food Colour is defined as “A food additive, which adds or restores colour in a food”. The food colour can be generally classified as Natural, Natural Identical and Synthetic.

 

 

WHY ADD COLOURANTS TO FOODS?

  1. Colour is a selection criterion among consumers.
  2. For number of food products colour is considered as a quality parameter.
  3. To reduce batch to batch variation.
  4. To restore the colour lost in processing.

CLASSIFICATION OF FOOD COLOURANTS

a)  Natural food colour: It is any dye, pigment or any other substance obtained from vegetable, animal, a mineral that is capable of colouring foods. Colours come from a variety of sources like seeds, fruits, vegetables, algae and insects. Grass, beetroot, and turmeric are some of the natural sources of colours. The main noticed property among the natural colours is the instability of colours in pH & temperature. This particular property is in contrast to the synthetic and natural identical one. To cop up with this particular situation, technologies involved in plant cell and tissue culture, microbial fermentation and gene manipulation have been applied to that of mass production of stable pigments. These approaches have not yet been approved in terms of human-use.

Some of the products in market with natural colours are Boost, Thumsup, Coca-Cola and Bournvita.

S.No. Colour Derivative
1. Anthocyanins Glycosidic  derivatives  of  the  2-phenylbenzophyrylium

structure

2. Carotenoids Aliphatic and alicyclic unsaturated terpenes composed of

eight isoprene units

3. Xanthophylls Closely  related  to  carotenes  but  have  keto  /hydroxyl

substituents

4. Betalines Quaternary ammonium derivatives of 4-vinyl-5,6-

dihydropyridine-2,6-dicarboxylic acid

5. Caramel Heating a food grade carbohydrate like glucose, sucrose

or starch in the presence of catalyst acetic sulphurous or citric acid or bases such as ammonium, calcium and sodium hydroxides.

 

Sources of natural food colours

S.No. Food Colourant Colour Source
1. Anthocyanin Red to Blue Mature Fruits (Strawberry, Blueberries

etc), Vegetables (Onions, Cabbages).

2. Betalins Red Beetroots
3. Caramel Brown to dark brown Catalytic heating of carbohydrates
4. Carmic Acid or

Carmine

Red Female Cochineal Insects
5. Lycopene Deep-Red Tomato
6. Chlorophyll Green Green leafs
7. Curcumin Yellow Turmeric

 

b)  Nature (Identical food colourants): Members of this class are actually compounds synthesised to the chemical identity of the natural colourants. Examples include ?- carotene, canthaxanthin and ribo?avin. Generally, the majority (if not all) of the natural and nature-identical colours are hydrophobic, that is,  mostly insoluble in water. This makes the application difficult in real like usage. One way of introducing them into foods is to convert them into their sodium or potassium salt forms, making them hydrophilic and hence soluble in water. Another approach that is normally used is to dissolve them in a hydrophobic medium such as oil, and then introduce them into water-soluble platforms which can be introduced in foods.

c) Synthetic/ Arti?cial food colourants: These colours are made out of chemical processes. Examples include carmoisine and tartrazine. They are mainly hydrophilic in nature (water-soluble) which means without pre-processing they can be introduced in the food. Synthetic food colours include azo dyes (amaranth), quinolone (quinoline yellow), xanthene (erythrosine), triarylmethanes and indigoid (indigo carmine). The main classes of synthetic food colours are azo dyes (e.g. amaranth); quinoline (e.g. quinoline yellow); xanthene (e.g. erythrosine); triarylmethanes and indigoid (e.g. indigo carmine). The major disadvantage with the usage of artificial colour is that the consumers are having a chemical-free notion in the selection of foods. Lately, some of the used colours in the last decades were banned by most of the worldwide regulatory bodies. Such as Blue #1 and Blue #2.

                                                          Synthetic colours permitted in food

SNo. Common Name Colour
1. Ponceau 4R Carmosine Erythrosine Red
2. Tartrazine,sunset yellow F.C.F Yellow
3. Indigo carmine

Brilliant Blue F.C.F

Blue
4. Fast green F.C.F Green

The synthetic colours are permitted to be used only in certain foods with a declaration on the label. The maximum quantity permitted is 200 mg/kg. Some of the foods in which food colour is permitted are ice –  cream, biscuits, cakes, sugar, boiled confectionery, sweets and savouries, fruit syrup, fruit squash, fruit drink, soft drink, jam, carbonated water, ready to serve beverages and synthetic syrup. Congo Red, Malachite green, orange Red, Sudan III and lead chromate are harmful hence prohibited to be used in food preparations. The pink dye Rhodamine B, Orange RN II and Blue VRS are carcinogenic and cause disruption of various organs like kidney, spleen and liver. Metanil yellow causes degeneration of reproductive organs. Hence, it is essential for consumers to be aware of these colours and properly read the label before buying the foodstuff.

Author

Muhammad Salman Chukkan  is MTech, Final Year Food Engineering and Technology Institute of Chemical Technology, Mumbai

Anusha Mishra is Research Scholar Department of Food Engineering and Technology Institute of Chemical Technology, Mumbai.

 

Share Button

Webmaster LBA

Food Marketing & Technology is a monthly magazine published by L.B. Associates Pvt Ltd

Comments are closed