Upcycling Sugar Mill Byproducts into Policosanols via Supercritical CO₂ and Liquefied Extraction Technologies

Sugarcane leaves and filter mud represent valuable sources of policosanols, a bioactive compound known for its cholesterol-lowering properties. Policosanol extraction efficiency by liquefied dimethyl ether (LDME) was compared with that by supercritical fluid carbon dioxide (SF-CO₂) under optimized conditions. The sugarcane filter mud (SG-FM) contains higher policosanol content than sugarcane leaves (SG-L), whereas the leaves exhibit greater antioxidant activities. By supercritical fluid carbon dioxide, both temperature and pressure had a highly significant influence on policosanol contents of filter mud (p < 0.01), while only pressure had the significantly highest impact (p < 0.01) on policosanol contents of the leaves (p < 0.05). Compared with supercritical fluid carbon dioxide, liquefied dimethyl ether gave a high extraction percentage and policosanol content for both SG-FM (3,120.95 mg 100 g^-1) and SG-L (2,134.27 mg 100 g^-1). Policosanols extracted by liquefied dimethyl ether were 3.9-fold and 2.8-fold higher than that by supercritical fluid extraction for SG-FM and SG-L, respectively. There was no correlation between policosanols and antioxidant properties. Liquefied dimethyl ether and supercritical fluid carbon dioxide demonstrated the potential to convert industrial waste into high-value nutraceuticals with cholesterol-lowering properties.