AN OVERVIEW OF PIGMENT PRODUCTION IN BIOLOGICAL-SYSTEMS - FUNCTIONS, BIOSYNTHESIS, AND APPLICATIONS IN FOOD-INDUSTRY

Since times immemorial, colors in the living world have always fascina ted and amazed humans and left them wonderstruck; the present study ha s also been inspired by their provocative and conspicuous nature. The structural colors, wherein a variety of optical properties emerge as a result of the physical nature of the surface of the tissue, are, howe ver, excluded from the present review. To give a brief account, two pr edominant structural colors encountered in the biological systems are Tyndall blue colors and iridescent colors. The former are produced as a result of light scattering by very small particles, examples being t he color of human eyes and feathers of many birds. The iridescent colo rs result from interference with light by thin films or laminations, a nd examples of such colors are abundant in the animal kingdom, in bird s, insects, and fishes. It should be noted that no pigment per se is e xtractable in either of the structural colors discussed. For a detaile d account, the readers may refer to Fox (1). The present review deals with pigments or biochromes, the chemical compounds absorbing specific wavelengths of visible light. A broad spectrum of pigments produced i n the biological systems are reviewed in relation to their distributio n and occurrence in the living world as well as the types, functions, and applications of the pigments in industry and aquaculture. In the l ast part, attention is focused on the mechanisms of their biosynthesis .