Analysis of Food Bioactive Oligosaccharides by Thin‐Layer Chromatography

Abstract

IntroductionCarbohydrates are normally naturally occurring organic polyhydroxyl substances expressed by the empirical formula (CH 2 O) n, and their derivates. Sugars in foods and food products can be present as simple sugars -monosaccharides with low molecular weight and consisting of a single basic sugar unit -or as complex sugars -oligosaccharides and polysaccharides. Oligosaccharides are complex saccharides with a degree of polymerization (DP) of 2-9 and an intermediate molecular weight in which the monosaccharide units are linked by glycosidic bonds. Polysaccharides are complex sugars of high molecular weight and containing a large amount of monosaccharide units (polymers) joined by a glycosidic bond (DP > 10). In terms of nutrition the chemical composition of sugars is important, as are the degree of polymerization, the number of glycosidic linkages and the rate of digestibility in the intestine, because these attributes determine their physiological properties.Food bioactive oligosaccharides are a special group of carbohydrates that can be classified in the category of "nondigestible food ingredients". These compounds, also known as prebiotics, are complex carbohydrates, mainly fructooligosaccharides (FOS), galactooligosaccharides (GOS), and inulin of the non-α-glucan type, which resist hydrolysis by the salivary and intestinal digestive enzymes of man and other animals. For this reason, they are not absorbed or metabolized in the upper digestive tract and thus are able to reach the colon unaltered. In the colon they are rapidly fermented by a large number of intestinal bacteria and, subsequently, lead to the production of short-chain fatty acids (SCFA), mostly acetic, but also some propionic and butyric acid, which are necessary for the maintenance and renewal of the cells lining the large intestine. The addition of a limited amount of bioactive oligosaccharides to foodstuffs can result in the inhibition of the growth of pathogenic bacteria, stimulation of the immune system, and can have a positive effect on digestion, the absorption of nutrients, and the synthesis of vitamins indispensable to metabolism (for example folic acid) among other benefits.As discussed in Chapters 3, 4, 11 and 24, FOS are widely distributed in nature, such as in asparagus, onion, honey, beer, Jerusalem artichoke, wheat, rye, pine, banana and many others. The main FOS are composed of one molecule of sucrose (GF) and one to several molecules of fructose. Depending on the manner of bonding, the more known isomers of sucrose are: turanose, maltulose, leucrose and isomaltulose. GF 2 FOS, which are composed of one molecule glucose and two molecules of fructose, include 1-kestose, 6-kestose and neokestose. GF 3 FOS, which are composed of one molecule of glucose and three molecules of fructose, are nystose, bifurcose and neobifurcose, and GF 4 FOS is fructosylnystose.

Characterization and in vitro anticancer potential of exopolysaccharide extracted from a freshwater diatom Nitzschia palea (Kütz.) W.Sm. 1856

“…However, in our study, the TLC chromatogram had shown distinct spots of oligosaccharides derived from the exopolysaccharide of Nitzschia palea . The optimized mobile phase for TLC was chloroform, acetic acid, and water in the ratio of 6:7:1 reported according to Reiffova 36 .…”