In the food industry, composition and structure of human breast milk oligosaccharides cannot be reproduced. So, in order to obtain the potential beneficial effects of human breast milk oligosaccharides, then other oligosaccharides which are originated from animal and vegetal are produced and used in infant feeding. Those oligosaccharides, for example, are fructooligosaccharides (FOS) and galactooligosaccharides (GOS).
Fructooligosaccharides (FOS) are compounds with a vegetable origin. They are found in foods such as onions, asparagus, artichokes and tomatoes. Their chemical structure consists of a glucose molecule bound to two, three or four fructose molecules, producing kestose, nistose and frutosil–nistose. Industry obtains FOS from beetroot via the action of fructosilfuranosidase from Aspergillus niger (Bornet FRJ; Crittenden RG, et al; Hidaka H, et al.), causing the phenomenon known as “transfructosilation”. Galactooligosaccharides (GOS) are animal compounds provided by cow’s milk. They are obtained from lactose via transgalactosilation using b-D-galactosidase synthesised by Bacillus circulans (Chonan O, et al.).
FOS are resistant to the action of intestinal and pancreatic enzymes in the human small intestine. Undigested FOS in the human small intestine are broken down in the colon by anaerobic bacteria, the dominant flora. In general, GOS is digested similarly to FOS, as their molecules are also united by betatype links. Because of its properties, therefore FOS and GOS are classified to prebiotics since they meet with the criteria of prebiotics which are:
FOS and GOS are good substrates for bacteria of the types Bifidobacterium spp. and Bacteroides spp., as they possess the enzymes necessary to metabolize them and use them for growth and development. However, they are not a good substrate for Escherichia coli, Clostridium perfringens or S. mutans, since they do not possess these enzymes. FOS and GOS (simple oligosaccharides) have other potential beneficial effects in addition to the increase in bifidus-type flora:
In 1991, the Japanese Government included fructooligosaccharides (FOS) and galactooligosaccharides (GOS) among “foods for special medical uses”. Due to the great number of beneficial properties attributed to the oligosaccharides in the first months of life, some infant food companies have included them, FOS and GOS, in the composition of their products in an attempt to emulate the beneficial action of complex carbohydrates in human breast milk.
The beneficial effects of consuming oligosaccharides, such as fructooligosaccharides and galactooligosaccharides, both for nursing children and during other stages of life, have demonstrated their safety and efficacy.