Newton demonstrated that colour is the quality of light. The wavelength of light that an object reflects determines the colour. There are three primary colours red, green and blue which can be combined in different ways to make every other colour. Colour plays a role in the taste and perception of food and plays a very important role in the food industry as it gives consumers an impression of freshness, flavour and the quality of the product. The colour often determines why a consumer purchases a certain product and because of an association between colour and taste, coloured fruit is judged to have a better smell and stronger flavour.
In fruit and vegetables almost all colours are caused by just four groups of pigment:
- Chlorophyll (Green)
Green and earthy tones are associated with natural, organic and healthy foods.
- Carotenoids (Yellow, red and orange)
Yellow and orange make one feel hungry.
- Flavonoids (Red,blue and purple)
Group 1: Anthocyan
Group 2: Anthoxantins
- Betalains: (Red-violet and yellow).
Food colour is an important property of any food item with red and yellow as chief food colours, grabbing attention.
- Red indicates appetizing, ripeness and sweetness.
- Yellow, happiness, optimism and good feeling.
- Orange is vibrant and suggests vitality.
According to traditional Chinese medicine different colours of food benefit different organs:
- White for lungs and large intestine
- Orange and yellow for stomach and pankreas
- Red for heart and small intestine
- Green for liver and gallbladder
- Black for kidneys and bladder
Main colour food benefits are as follows:
- White for the immune system.
- Yellow for skin health and elasticity and healthy bones.
- Red improve cardiovascular conditions.
- Green is depurative for liver and body detox.
- Purple improves sight and anti-ageing.
- Orange is for skin and stomach and body detox.
Experts have long known the importance of colour in food as people eat with their eyes. Colour is crucial in the taste and perception of food and is added to ensure that consumers find them more appealing. To ensure that products are purchased by customers, the colour and appearance of goods always need to be uniform in colour. Varieties in colour may cause customers to question the quality, brand or recipe.
Modern customers are looking for natural colours but it remains a challenge to maintain stability in products. It is not easy to achieve vivid and bright colours with natural colours.
- Annatto is an orange-red condiment and food colouring derived from the seeds of the achiote tree (Bixa orellana) native to tropical regions from Mexico to Brazil.
- Betanin, or Beetroot Red, is a red glycosidic food dye obtained from beets. The most common uses of betanin are in colouring ice cream and powdered soft drink beverages; other uses are in some sugar confectionery, e.g. fondants, sugar strands, sugar coatings, and fruit or cream fillings. In hot processed candies, it can be used if added at the final part of the processing. Betanin is also used in soups as well as tomato and bacon products. Betanin has nearly no potential as an allergen.
- Chlorophyll (also chlorophyll) is any of several related green pigments found in the mesosomes of cyanobacteria, as well as in the chloroplasts of algae and plants.
- Iron oxides are chemical compounds composed of iron and oxygen. Oxides occur naturally and are available in red, yellow, and black. They are mostly earthy colours.
- Titanium dioxide (TiO2) is a naturally occurring mineral that is mined from the earth, processed and refined, and added to a variety of foods, as well as other consumer products. White in colour, is used to enhance the colour, sheen and in some cases give opacity.
- Turmeric is a flowering plant, Curcuma longa of the ginger family, Zingiberaceae, the roots of which are used in cooking. Turmeric powder has a warm, bitter, black pepper-like flavour and earthy, mustard-like aroma.
- Anthocyanins are a type of flavonoid, a class of compounds with antioxidant eﬀects. Found naturally in a number of foods, anthocyanins are the pigments that give red, purple, and blue plants their rich colouring. In addition to acting as antioxidants and fighting free radicals, anthocyanins may oﬀer anti-inflammatory benefits.
- Beta Carotene is an organic, strongly coloured yellow-orange-red pigment abundant in plants and fruits. It is a member of the carotenes,
- Lycopene is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables, such as red carrots, watermelons, grapefruits, and papayas, but it is not present in strawberries or cherries. Although lycopene is chemically a carotene, it has no vitamin A activity.
- Paprika or Paprika Extract is extracted from red fruits (Pepper), and capsicum annum L. is mostly grown in countries like Hungary, Spain, China, South America, Africa and USA. It is well known as a spice with a bit of pungent or peppery taste and is an important ingredient in many recipes. It gives a reddish-orange hue and varies from strength to strength in colour units.
- Caramel is a medium to dark-orange confectionery product made by heating a variety of sugars. It can be used as a flavouring in puddings and desserts, as a filling in bonbons, or as a topping for ice cream and custard.
When choosing an appropriate colour source it is necessary to find the most suitable option that can impact product stability and the following factors need to be taken into consideration:
Chlorophyll is hard to keep bright, Carotenoids lose colour due to oxidation. Most anthocyanins are not stable as they are very sensitive to the acidity of their environment, and Betalains are also sensitive to heat, light and pH and dissolve in water.
Quantum Colours, one of the top suppliers of synthetic colours, believes that with the increased demand for natural colours and the continuous growth of synthetic colours, both synthetic colours and natural colours will continue to exist and are therefore continuously looking at variously technologies to improve the effective use of natural colours and to bring stability to these products while still offering a wide variety of synthetic colours to suit customers needs.
Beta-carotene is offered in various sources and varying strengths to cater for natural yellow shades as well as the use of turmeric for an even brighter shade. Alternative offerings for red shades are explored while some colour blends are already on offer.
It remains a challenge to make and manage the change to natural colours, as the colour will always influence a customer’s decision to purchase food and food companies do need to control colour.
As Jack Francis from the University of Massachusetts warned “If you don’t have the colour right, one can forget about flavour and texture”.
Colour will always remain the crucial factor in the taste and perception of food.