Multifunctional cellulose-rich bagasse magnetic biochar capable of efficient elimination and separation of purine compounds in beer: DFT calculation and practical system applications.

Purine compounds in beer significantly increase the risk of hyperuricemia and gout, creating a strong demand for low-purine and healthy beer. A multifunctional cellulose-rich bagasse (cellulose content: 40 %-50 %) magnetic porous carbon (MABB) was constructed by employing alkali-modified bagasse and intercalating with Fe3+ to effectively remove three purine nucleosides (NUCs) in beer, namely, guanosine (GUA), adenosine (ADE), and inosine (INO). Characterization results showed that alkalization increased the specific surface area of MABB and iron oxide acted as an active site to facilitate NUC removal. The equilibrium adsorption capacities of MABB for GUA, ADE, and INO were 307.12, 317.16, and 303.37 mg/g, respectively. Analysis of adsorption mechanisms and density functional theory calculations revealed that pore adsorption, metal complexation, electrostatic attraction, and hydrogen bonding interactions are dominant in MABB adsorption of NUCs. In practical system of homemade beer, MABB demonstrated significant purine removal efficacy. The treatment achieved 82.66 % purine reduction (from initial 110.04 to residual 19.08 mg/L), thereby confirming its operational viability. While minor alterations in physicochemical parameters were observed post adsorption, all critical quality indicators remained compliant with brewing standards. This study proposes an effective adsorption-based strategy for purine removal, offering mechanistic insights and a theoretical framework for industrial low-purine beer production.