ABSTRACT
Nondigestible carbohydrates include some polysaccharides and oligosaccharides delivered intact to the large intestine. In the colon, these compounds show the ability to be selectively fermented stimulating the intestinal microbiota (several benecial systemic eects). Oligosaccharides with prebiotic properties have received great interest from both researchers and food industry due to their potential as ingredients for the formulation of functional foods (Barreteau et al. 2006; Mussatto and Mancilha 2007). Among the most cited, physiological benets of these compounds are the stimulation of the intestinal microbiota; production of short-chain fatty acids; reduction of intestinal pH; inhibition of the development of pathogenic microorganisms; decrease of gastrointestinal infections; decreased insulin response and glucose uptake; improvement of the lipoprotein prole; reduction of cancer development risk; and stimulation of the uptake of minerals, such as calcium, magnesium, and iron (Gobinath et al. 2010; Moure et al. 2006; Qiang et al. 2009). e introduction of oligosaccharides as functional ingredients in the food industry has increased, especially in beverages (fruit juices, coees, chocolates, and teas) and dairy products (yoghurt, powdered milk, and ice cream). Fructooligosaccharides (FOS) and galactooligosaccharides (GOS) are among the main commercially available oligosaccharides with bidogenic properties. A novel generation of oligosaccharides, namely, xylooligosaccharides (XOS), pecticoligosaccharides (POS), and agarooligosaccharides has received attention in recent years (Chen et al. 2013; Kang et al. 2014; Moure et al. 2006; Qiang et al. 2009). e properties of oligosaccharides dier with their composition, molecular weight, and structural linkages. ese characteristics are directly related to the natural source from which they are extracted and to the extraction process applied (Kang et al. 2014; Nabarlatz et al. 2007). In general, these oligomers are substantially composed of fructose, galactose, glucose, and/or xylose monomers. eir degree of purity is also very important with respect to the physiological eects. Some methods for oligosaccharides production can generate products with the presence of salts or other nonsaccharide compounds, unhydrolyzed polysaccharides, or monosaccharides. In this case, the elimination of these compounds appears mandatory. e reduction of the amount of nonsaccharide compounds present in the medium is very important to increase the quality of the nal product for prebiotic applications (Gullon et al. 2011). Although there are some
oligosaccharides with prebiotic properties commercially available (FOS and GOS), there is an increasing interest in the development of new prebiotics with added functionality. Production of this functional ingredient in large scale requires constantly the developing of new techniques but also improving the existing ones (Gullon et al. 2011; Kang et al. 2014). e synthesis of oligosaccharides is more complex than that of other polymers due to the several combinations of monomer units. Moreover, specic enzymes and highly controlled reaction conditions are necessary, usually resulting in a lower yield. erefore, the synthesis process is more expensive and dicult to reproduce on a large scale. Obtaining oligosaccharides from the hydrolysis of polysaccharides is often simpler, has lower costs, and is more reproducible on an industrial scale (Barreteau et al. 2006). However, the peculiarities inherent to each hydrolysis method proposed in the literature can yield dierent qualitative and productive eciencies.
