(a: solid-liquid ratio; b: enzyme concentration; c: enzyme hydrolysis temperature; d: enzyme hydrolysis time)
3.4. PCA of characteristic wave numbers ofcell wall polysaccharides
The PCA scatter plots of the FT-IR spectra of cell wall polysaccharides in the 1800-800 cm-1 region is shown in Fig. 6. The changes of infrared spectroscopy in the main components of the cell wall (cellulose, hemicellulose, and pectin) under different extraction conditions were explained by PC1 and PC2. PC1 and PC2 indicated that cell wall residues were grouped or scattered in group along the PC2 axis and PC1 axis, respectively. Not only reflected difference between groups of cellulose, hemicellulose, and pectin, but also reflected differences in the group of cellulose, hemicellulose, and pectin affected by solid-liquid ratio, enzyme concentration, enzyme hydrolysis temperature, and enzyme hydrolysis time.