Optimisation and characterisation of KOH-activated carbon obtained from Baijiu spent grains for the mitigation of risk factors in alcoholic beverages

Abstract

This study aims to repurpose waste grain from the Baijiu brewing process into activated carbon for mitigating risk factors in alcoholic beverages, enhancing quality and ensuring safety. For attaining the most effective activated carbon, tailored carbon synthesis conditions were identified for diverse alcoholic beverages, optimising strategies. For beverages with low flavour compound content, optimal conditions include 900 °C calcination, 16-hour activation and a 1:2 activation ratio. In contrast, for those with abundant flavour compounds, 800 °C calcination, 16-hour activation and a 1:1 activation ratio are recommended. Post-synthesis analyses, employing nitrogen physisorption–desorption isotherms, FT-IR and SEM, validated a significant BET surface area of 244.871 m2/g for the KOH-activated carbon. Critical to adsorption efficiency, calcination temperature showcased noteworthy micro-porosity (0.8–1 nm), selectively adsorbing higher alcohols (C3–C6) and acetaldehyde while minimising acid and ester adsorption. Sensory evaluations refined optimal parameters, ensuring efficient spent grain management and heightened beverage safety without compromising aroma.