Structural characteristics of hemicelluloses and lignin-carbohydrate complexes in alkaline-extracted bamboo green, core, and yellow

Understanding the differences in the chemical structures of important components in different bamboo tissues is crucial for maximizing bamboo utilization and biorefining bamboo resources. Hemicellulose and lignin-carbohydrate complex (LCC) were extracted from bamboo green, bamboo core, and bamboo yellow tissues by using the alkali-leaching method, and the chemical composition, thermal stability, dissolution process, and structural characteristics were analyzed. The extraction yield of hemicelluloses followed the order: bamboo yellow > bamboo core > bamboo green. Hemicelluloses extracted from bamboo green mainly originated from the secondary wall (S-layer) of the fiber cells and parenchyma cell walls, while those from the bamboo core and yellow mainly originated from the inner S-layer and outer S-layer of the fiber cells, as well as the parenchyma cell walls. The LCCs from bamboo core and bamboo yellow contained a large number of type I phenyl glycoside (PhGlc₁) bonds, which mainly originated from the parenchyma cell walls of these tissues. These findings provide data on the structural differences between carbohydrate components in green, core, and yellow bamboo, offering valuable guidance for the high-value utilization of different bamboo tissues.