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

For analysing the non-starch polysaccharides (NSP) of tomatoes, the alcohol -insoluble solids were fractionated using water, EDTA solution and sodium h ydroxide solution, and the sugar and uronic acid components were determined by capillary gas chromatography. Highest yields of monosaccharides were ob tained when the pectin and cellulose fractions were treated with methanesul fonic acid prior to methanolysis by diluting with methanol and heating to 1 00 degrees C for 2 h. However, treatment with concentrated formic acid foll owed 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) wer e characterized for their monosaccharide pattern. Free and associated pecti ns amounted to 28%, xyloglucans and other hemicelluloses to 30% and cellulo se to 23%.