**1. Introduction**

Colouring is an important aspect of our lives for many decades. It may be the clothes we wear, furnishings of our home, religious ceremonies and even the food we relish. The various evidence related to synthetic colours usage showed harmful effects over the years, now a day's need of consumers is shifting towards bio-colours. There is an emerging trend for the use of bio-colours as they are available naturally and are non-renewable [1].

A recent survey conducted in northern Kerala revealed excessive use of synthetic colours in sugar-based confections, posing a serious health risk, especially for children. Out of the 14 samples collected from different locations showed 97 per cent of non-permitted colours. On analysis about 82 per cent showed the higher level of permitted colours than the required limit (more than 100 ppm) [2].

Colour is a molecule that absorbs certain wavelengths of visible light and transmits or reflects others [3]. It will correct the natural variations in colour and enhance the colours that occur naturally. It is added mainly to maintain or improve the safety and freshness of the food material. It will also improve taste, texture, appearance and thereby its nutritional value [4].

Colours are mainly classified into four different types *viz*., **Natural colours** are pigments obtained from living organisms such as caramel, anthocyanin, betaline. **Nature - identical colours** are man-made pigments which are also found in nature *e.g*. Carotene. **Synthetic colours** are man-made colours that are not found in nature, these are often azo-dyes and Allura red and **Inorganic colours** are non-edible which are used in paints and plastics [5].
