Effects of different extraction methods on microstructure of tobacco cellulose

In order to investigate the effects of different extraction methods on the microstructure of tobacco cellulose, the cellulose of flue-cured and oriental tobacco leaves was extracted by neutral detergent method, acid detergent method, acid hydrolysis method and alkali treatment method. The microstructure of tobacco cellulose extracted by different methods was characterized by solid-state cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS ¹³C NMR). The yields and purity of tobacco cellulose extracted by the four methods were comparatively analyzed. The structural information such as crystal form and distribution, crystallinity and fibril size of tobacco cellulose were obtained by fitting the absorption peaks of NMR spectra. The results showed that:1) The purity of tobacco cellulose extracted by neutral detergent method was higher than the other three methods. 2) The tobacco cellulose extracted by the four methods had the same crystal form with the dominant cellulose form of I_β crystal, however the crystal form distribution was significantly different. 3) Among the four extraction methods, the cellulose extracted by neutral detergent method had the highest crystallinity, and the sizes of elementary fibrils and elementary fibril aggregates were the largest. Compared with the other three methods, the influence of neutral detergent method on the microstructure of tobacco cellulose was the slightest. Thus, for the study of tobacco cellulose microstructure, neutral detergent method is a suitable cellulose extraction method.