Selective reduction of hazardous volatiles from baijiu using spent grain-derived activated carbon: Flavor preservation and DFT-elucidated adsorption mechanisms.

Excessive methanol, acetaldehyde, and higher alcohols in baijiu pose health risks and impair quality. We developed a functional activated carbon from baijiu spent grains via ZnCl₂ activation, tailored for selective reduction of these risk factors while preserving key flavor compounds. The optimized carbon, comprehensively characterized by multidimensional structural analyses, featured micropores (0.7-1.5 nm) and abundant surface hydroxyl/carboxyl groups, achieving 3-15-fold higher selectivity than commercial adsorbents. Under sensory-guided conditions (≤0.15% w/v, ≤2 h), acetaldehyde and total higher alcohols were reduced by 16.70% and 17.68%, respectively-phenylethanol and isopentanol decreased by 33.97% and 19.20%-with no significant flavor alteration confirmed by trained panelists. Density functional theory revealed adsorption stability governed by polarity, steric bulk, and van der Waals interactions, following the order: isopentanol > methanol > acetaldehyde > acetic acid > ethyl acetate, consistent with experimental data. This sustainable adsorbent enhances baijiu safety without compromising sensory quality.