Color is the most important attribute of any article especially food. Biocolorants are those coloring agents, which are obtained from the biological sources. Biocolorants are mainly derived from plants, animals and microbes are sources of natural pigments. In the recent years, coloring of food with pigments produced from natural sources is of worldwide interest and is gaining importance. These pigments are looked upon for their safe use as a natural food dye in replacement of synthetic ones. Synthetic colorants tends to impart undesirable taste and harmful to human beings, as these are responsible for allergenic and intolerance reactions. A well textured food, rich in nutrients and flavor, cannot be eaten unless it has the right color. The demand for natural source of such compounds is increasing day by day because of awareness of positive health benefits out of natural compounds. Food industry in general, generates a large quantity of waste (i.e. peel, seed, pomace, rags kernels, etc.) which is biodegradable in nature. Due to richness in carbohydrates, dietary fibers and minerals, wastes have the potential to support the growth of microorganism involved in the production of various value added products. The utilization of food industry waste is also important to overcome the menace of environmental pollution.

        Spent Grain – A waste from Brewery

•  It is generated after the extraction of wort from the Malt for beer production.
• It is used as a animal feed or for extraction of other valuable products such as alcohol.
• Presently, Most of the spent grains are used in different forms in animals feedstuffs: fresh spent grain and dried spent grains.
• So, production of microbial color using spent grain as a substrate will be an alternative to utilize this waste.

Color is added to food for one of the following reasons: to replace color in the food, which is lost during processing, to enhance color of food already present, to minimize batch-to-batch variations, to color otherwise uncolored food, and to supplement food with nutrients.

Microbial pigments: Plants, animals and microbes are the source of natural pigments. When the microbial cells are used to produce the color the term refers to ‘Microbial Pigments’. Micro-organisms are associated with all the foods that we eat and are responsible for the formation of certain food products by the process of fermentation and can also be used as a source of food in the form of single cell proteins and food supplements in the form of pigments, amino acids, vitamins, organic acids, and enzymes. In this way the pigments from microbial sources are a good alternative. Micro-organism are known to produce a variety of pigments, therefore they are promising source of food colorants. Most of the bacteria, algae and fungi are widely studied for their potential as a source of food colorants. Natural pigments possess anticancer activity, contain pro-vitamin A and have some desirable properties like stability to light, heat and pH. Thus, the food industry has become increasingly interested in the use of microbial technology to produce colors for use in foods. The various advantages of producing pigments from micro-organisms include independence from weather conditions, easy and fast growth and colors of different shades can be obtained by growing on cheap substrates.

Sources of natural colorants:

1.      Plants (Flowers, Fruits, seeds, roots etc.)

2.      Animals (Cochineal, lac etc.)

3.      Microorganisms (Monascus, Rhodotorulla, Bacillus, Achromobacter, Phaffia etc.)

Table 1: Naturally derived colors from plants source

Table 2: Naturally derived colors from micro-organism

But only few of them are available in sufficient quantities for commercial use as food colorants. They are mostly of plant origin. For biotechnological production, plants and microorganisms are more suitable due to greater understanding of their proper cultural and processing techniques.