Browsing by Subject "methylation"

Methylation analysis by Ciucanu and Kerek (1984) and Hakomori (1964) and the meaning of circumstances in the reaction, reaction parameters and structure of the sample were reviewed in this study. The experimental work consisted of methylation analysis of glucose, cellobiose, isomaltose, pullulan, commercial dextran and dextrans produced by lactic acid bacteria Weissella confusa and Leuconostoc citreum. The success of the methylation was controlled using the IR-method. Methylated samples were treated by methanolysis and acid hydrolysis. The structure analyses were carried out with GC-MSspectra. Two different columns: DB-1 and HP-5 were compared in the GC-analysis. Two hours methylation in the ultrasonic bath gave good methylation results. It was easy to control the methylation by IR-method. OH-peak (3400 cm-1) was absent and CH3- peaks (2900 and 2800 cm-1) were high after successful methylation. IR-spectroscopy is a valuable tool to check if methylation has been successful. Samples could be remethylated before hydrolysis and derivation if necessary. After methanolysis there were ?- and ?-pyranose forms from each methylated monosaccharides. Due to reduction after the acid hydrolysis method, there was only one methylated form from each product. The structures of glucose, cellobiose, isomaltose and pullulan were solved by both hydrolysis methods. Recovery of these samples was good but the deviation was large. The structure of commercial dextran and dextran produced by W. confusa were solved by methanolysis method and partly by acid hydrolysis method. Recovery of these samples was poor. The methylation succeeded only in one of the dextran samples produced by L. citreum. The methylation analysis of dextrans could be developed in the future by increasing the temperature and the time of mixing and by adding some glycerol.