Obtaining value-added products from cashew apple bagasse: A sustainable alternative achieved through a hydrothermal...

The processing of cashew peduncles annually generates approximately 4000 tons of cashew apple bagasse, a biomass rich in value-added products. Pressurized liquid extraction (PLE) was employed to extract bioactive compounds using a Box-Behnken design, with temperature, pH, and solid-liquid ratio as the independent variables. The study evaluated pectin yield, total phenolic compounds (TPC), antioxidant activity (FRAP), sugars, and organic acids. Results were compared to a conventional agitation method (90 °C, 2 h, pH 2.0). Under optimized conditions of 120 °C, pH 2.0, and a solid-to-liquid ratio (S/F) of 15, the PLE method achieved a high pectin yield (23.37 % g g^-1), surpassing the conventional method (21.40 % g g^-1). Optimal sugar extraction was observed at 100 °C, pH 2.0, and S/F of 10, with a recovery of 90.41 mg per gram of cashew apple bagasse. TPC yields were higher at 120 °C, whereas antioxidant activity peaked at 100 °C. Formic acid concentrations were higher in treatments with low sugar recovery, suggesting compound degradation. Notably, the conventional method produced a higher concentration of formic acid, likely due to the extended extraction time. The kinetic study revealed the formation and recovery patterns of bioactive compounds over time. TPC and FRAP were continuously recovered throughout the studied period, while approximately 80 % of the pectin and sugar yields were achieved within the first 15 min of extraction. Morphological and structural analyses highlighted the impact of the extraction process on the cashew apple bagasse and the resulting pectins. The application of pressure-enhanced porosity in the pectin structure improved thermal stability, significantly reducing the material's hemicellulose fraction. The Ecoscale Environmental Assessment scored 89.75 for pectin extraction and 93 for TPC recovery, surpassing other extraction methods reported in the literature. These findings contribute to the valorization of agro-industrial waste and the development of high-value products from cashew apple bagasse, offering significant potential for the processing industry.