Extraction of Bamboo Sap by High-Efficiency Hot Pressing: A Method for High Value and Sustainable Use of the Bamboo Material.

To develop an effective and eco-friendly method for extracting bamboo sap can effectively improve the utilization of bamboo resources and promote the sustainable development of the bamboo industry. In this work, fresh bamboo strips were directly placed into a hot press for hot pressing (HP), yielding both pure bamboo sap and flattened, dense bamboo strips. The physicochemical properties of bamboo sap and bamboo strips were systematically investigated. The results indicated that the HP method offers significant advantages in terms of the bamboo sap extraction efficiency and the mechanical properties of bamboo. The bamboo sap extracted through HP exhibited a guaiacol concentration comparable to that obtained via the traditional baking method, while the levels of total flavonoids, amino acids, and total phenols were notably higher. The density distribution of the hot-pressed bamboo strips was uniform with a bending strength of 263 MPa and a modulus of elasticity of 14.04 GPa, reflecting enhancements of 45.30% and 65.17%, respectively. Furthermore, the hot-pressed bamboo demonstrates excellent dimensional stability, thereby expanding its potential applications in construction and furniture. The HP method achieves the simultaneous extraction of bamboo sap and the physical modification of bamboo strips, significantly improving resource utilization efficiency, minimizing waste, and simplifying the steps involved in traditional methods, ultimately showcasing considerable environmental benefits.