Valorization of ucuúba (Virola surinamensis) press cake using green extraction methods

Ucuúba seeds have a high fat content, which is highly valued by the cosmetics industry due to their richness in saturated fatty acids (SFAs). The extraction of fat from the seeds results in a press cake co-product, rich in bioactive components such as antioxidants. The aim of this work was to characterize the press cake (C1) resulting from the hydraulic pressing of shelled ucuúba seeds, and to evaluate the influence of residual fat on the recovery of compounds with antioxidant potential, by defatting pretreatment to obtain the degreased cake (C2). Following the biorefinery concept, C1 and C2 were subjected to extractions using ethanol and hydroethanolic solutions through three different methods: Soxhlet (SOX), Microwave-Assisted Extraction (MAE), and Pressurized Liquid Extraction (PLE). The extracts were analyzed for total phenolic content (TPC), total flavonoid content (TFC), total carotenoid content (TCC), and antioxidant potential by ABTS and DPPH assays. The most abundant macronutrients from C1 were total carbohydrates content (43.32 g 100 g⁻¹), lipids (33.24 g 100 g⁻¹), and protein (15.09 g 100 g⁻¹). The highest extraction yields were obtained from C1 by MAE and PLE with 100% ethanol. Extract by MAE with ethanol 70% from C2 showed the highest values of TPC (126.78 mg GAE g⁻¹), TCC (18.74 mg BCE g⁻¹), and antioxidant activity by DPPH assay (791.71 µmol TE g⁻¹), while SOX with ethanol 50% provided the highest TFC (13.10 mg QE g⁻¹), and with 100% ethanol showed the highest ABTS (1286.69 µmol TE g⁻¹). The main phenolic compounds found in samples extracted with ethanol 70% were ferulic acid (12788.94–14885.64 μg g⁻¹), vanillic acid (1388.36–3021.41 μg g⁻¹), and vanillin (809.75–1778.66 μg g⁻¹). Therefore, extracts from the degreased cake C2 showed higher concentrations of bioactive compounds with antioxidant potential, evidencing the positive effect of the defatting pretreatment. Additionally, the optimization of the alternative methods such as MAE and PLE may contribute to the valorization of this underutilized biomass.