Non-starch polysaccharides of tomatoes I. Characterizing pectins and hemicelluloses

Abstract

 For analysing the non-starch polysaccharides (NSP) of tomatoes, the alcohol-insoluble solids were fractionated using water, EDTA solution and sodium hydroxide solution, and the sugar and uronic acid components were determined by capillary gas chromatography. Highest yields of monosaccharides were obtained when the pectin and cellulose fractions were treated with methanesulfonic acid prior to methanolysis by diluting with methanol and heating to 100  °C for 2 h. However, treatment with concentrated formic acid followed by methanolic hydrochloric acid was best suited for the hemicellulose fractions. In this way, 81% of total tomato NSP (5.1 g/kg fresh weight) were characterized for their monosaccharide pattern. Free and associated pectins amounted to 28%, xyloglucans and other hemicelluloses to 30% and cellulose to 23%.