With the usage of natural food colourants, nutritional value as well as appearance of food products is maintained  Public concerns regarding safety of using synthetic colourants have resulted in high demand for natural colorants, which is used in food products for garnishing and making it more appealing to consumers. Natural colours are safe for human consumption as it does not cause side effects. Natural colours that are extracted from flowers, fruits, vegetables and seeds are used as source for improving colour of juices, canned food and confectionery items such as cakes and marzipans. Colours obtained from natural sources include yellow from Curcuma longa, purple from Hibiscus rosasinensis, red from Pterocarpus Santalinus and now blue from Clitoria ternatea.
An interesting source of natural colour used in food and cosmeticsis Butterfly pea (Clitorea terneta), a plant species belonging to the Fabaceae family. Anthocyanins, which are the key colouring compounds in its petals, can be extracted easily with help of water. These compounds are delphinidin glycoside that gives them the blue colour, safe for human consumption. It has been noticed that the colour of butterfly pea is most stable in pH 4 solutions under darkness, while it is least stable in pH 7 solution under UV rays. In other words, increasing temperature leads to loss of the colour. It is grown as an ornamental plant and requires limited care during its cultivation. The roots of the plant fix nitrogen, which is essential for improving soil quality.
The application of a particular natural colour depends on various factors such as temperature, pH level, light storage and different ingredients present in food products. The food products having natural colours should be kept in cold storage warehouses, which would help to preserve the colour, strength and quality of the product.
With technology advancement, various artificial products have been entering the domestic market, which can cause hazards to human health. However, food specialists have been striving to help manufacturers of food and beverages to utilise naturally derived products and limit the usage of chemicals, while also enhancing the appearance of food products.
Challenges
Although natural colourants are safe for human consumption, there are certain limitations of such products. Storage of natural colourants happens to be a major challenge. For example, turmeric is a natural colourant containing curcumin, which imparts a distinctive yellow colour. It is used as an essential ingredient in every Indian dish loses its colour strength in the presence of light. Therefore, it has to be cautiously stored in air tight containers away from high temperature.
Caroteniod colourant is another product that is used in juices. This provides orange and yellow colours to food products. It has been noticed that despite carotenes providing acid stability, it is oil-soluble and contains certain emulsifiers that lower the quality standard of beverages.
Proper research should be conducted in order to improve the quality of natural food colourants, thereby minimising the usage of artificial colours, even though the latter make food products look more appealing than the former. This would help consumers to purchase food products that are not only visually appealing but also high in nutritional value.
Sindhu Sridhar, food technologist in Ooty, Tamil Nadu |
