Toward sustainable wax extraction from the Saccharum officinarum L. filter cake byproduct: process optimization, physicochemical characterization, and antioxidant performance

Saccharum officinarum L. exploitation and processing result in different byproducts, such as filter cake (FC). This study aimed to establish the most suitable experimental conditions to obtain lipophilic bioactive compounds from FC industrial residues, considering their high efficiency, cost-effectiveness, extraction yield, composition, and physicochemical properties. Results indicated that the most appropriate methodology consisted of the pretreatment of the FC sample with H₂SO₄, followed by ethanolic extraction (B6 method), avoiding energy-consumption FC drying steps and providing ethanol recovery (approx. 90%). The obtained B6 extract yield was 9.59 ± 0.27 g/100 g of FC dry weight, and this methodology proved to be more efficient in obtaining fatty alcohols (20.28 ± 1.48 g/kg extract) and phytosterols (31.56 ± 0.18 g/kg extract) while maintaining lower total monosaccharide concentration (26.19 ± 1.82 mg/g extract). Furthermore, the geographically related multivariate analysis in wax composition and antioxidant activity was evaluated by comparing B6 waxes from Guariba (G) and Univalem (U), both provided by Brazil and collected in June 2020. Overall, the wax composition is affected, but the antioxidant activity is uncompromised, which indicates that the optimized wax extraction method can be applied to FC.