Abstract

Food colourants are pigments or dyes added to food to maintain, intensify or add colour to foods. Although, the initial natural sources of food colourants were plants and animals, these sources have become inadequate due to increase in demand. This led to the use of synthetic colourants, some of which have harmful effects on human. Filamentous fungi are good sources of colourants since they are capable of synthesizing large quantities of pigments with different colour sheds. Various genera of filamentous fungi such as Monascus, Penicillium, Talaromyces and Fusarium, have been used for colourant production. Some fungal pigments also have antimicrobial, antioxidant and cholesterol lowering effects. However, some fungi co-produce pigments with mycotoxins such as citrinin. It is therefore necessary to select non-citrinin producing fungal strains or employ culture conditions that limit citrinin biosynthesis. Production of fungal pigments is affected by some nutritional and environmental factors such as carbon and nitrogen sources, pH, temperature, light, moisture, agitation speed and dissolved oxygen concentration. This article highlights major species of pigment-producing filamentous fungi, antimicrobial activities of fungal pigments, and control of pigment and mycotoxin co-production by fungi. The nutritional and culture parameters that affect pigment production by the fungi are discussed in details.

Key words: Food colourant, pigments, fungi, antimicrobial substances, antioxidants, culture conditions.