To successfully prepare cellulose hydrogels through a dissolution–regeneration process, 60 wt% LiBr aqueous solution was used as a green solvent. Carboxyl groups were precisely introduced onto the surface of the cellulose hydrogels through a TEMPO-mediated oxidation reaction, while the three-dimensional network structure and open pore morphology were completely retained. This modification strategy significantly enhanced the loading capacity of the hydrogels with copper nanoparticles (Cu NPs). The experimental results show that the LiBr aqueous solution can efficiently dissolve cellulose, and the TEMPO oxidation introduces carboxyl groups without destroying the stability of the hydrogels. Cu NPs are uniformly dispersed and highly loaded on the surface of the hydrogel because of the anchoring effect of the carboxyl groups. Cu NP-loaded hydrogels exhibit excellent catalytic activity in the NaBH₄ reduction of 4-nitrophenol (4-NP). Cu NP-loaded hydrogels maintain their complete structure and good catalytic performance after five consecutive cycles. Moreover, Cu NP-loaded hydrogels demonstrate high efficiency in degrading organic dyes such as methyl orange and Congo red. This study successfully developed efficient, low-cost, and environmentally friendly Cu NP-loaded hydrogel catalysts through the synergistic effect of LiBr green solvent and TEMPO oxidation modification, providing a feasible alternative to noble metal catalysts.

Bamboo shoots are valued as traditional vegetables, but their palatability is often compromised by bitter and astringent compounds. The spatial and temporal distribution of these compounds across species, tissues, and developmental stages remains poorly characterized. This study systematically investigated key taste-active compounds (tannins, oxalic acid, flavonoids, cyanide compounds, and free amino acids) in three sympodial bamboo species (Bambusa chungii, Dendrocalamus farinosus, and Bambusa oldhamii). We integrated quantitative chemical analysis of shoots at different emergence stages and tissue parts with descriptive sensory evaluation. The results revealed pronounced, species-specific accumulation patterns. For instance, tannin content increased with shoot emergence in all species, whereas oxalic acid and cyanide showed divergent temporal trends among them. Tissue-specific gradients were also evident for most compounds. Correlation analysis with sensory data indicated distinct associations for each species. Bitterness in D. farinosus was most strongly correlated with oxalic acid, while in B. oldhamii, it was closely linked to tannins and cyanide. In B. chungii, specific amino acids (aspartic acid, histidine) and tannins showed significant correlations with bitterness perception. The perception of astringency involved multiple contributing factors. These findings elucidate the distinct biochemical bases of flavor variation in sympodial bamboos. They provide a scientific rationale for optimizing harvest timing and tissue selection, offering targeted strategies for post-harvest processing to improve edible quality and market value.