Galactooligosaccharides: novel components of designer foods.

Since introduction of functional foods, commercialization of the traditionally used probiotics has ushered in more followers into the new fraternity of sophisticated, health-conscious consumers. In 1995, this was followed by the first introduction of prebiotics. Prebiotics are defined as "a non-digestible feed supplement, beneficially affecting the host by selectively stimulating growth and/or activity in one or a limited number of bacteria in the colon." The number of new product introductions with prebiotics has steeply increased over the last few years. Paradoxically, probiotics have limited applications as these cannot be used in wide range of food products because of their viability issue. Fortunately, prebiotics do not suffer from any such constraint and can be used in a wide range of food products. Probiotics do not have a long shelf life in their active form. In most cases, refrigeration is required to maintain the shelf life. While probiotics are predominantly used in fermented dairy products, the use of prebiotics has expanded into other food categories. Prebiotics have successfully been incorporated in a wide variety of human food products such as baked goods, sweeteners, yoghurts, nutrition bars, and meal replacement shakes. For instance, the introduction of galacto-oligosaccharides (GOS) into baby foods has been very successful. GOS, which are identical to the human milk oligosaccharides, has emerged with strong clinical support for both digestive and immune health. Various aspects related to GOS such as types and functions of functional food constituents with special reference to GOS, their role as prebiotics, and enhanced industrial production through microbial intervention are dealt in this review.