Multi-objective optimization of autohydrolysis of Prunus avium stones for hemicellulose extraction, obtaining high-value products

Prunus avium stones represent an agro-industrial waste with considerable potential to produce value-added bioproducts. This study examines the impact of temperature, time, and liquid-solid ratio on the autohydrolysis of Prunus avium shell stones (CSS) to ascertain their effect on hemicellulose extraction and on subsequent production of a cellulose- and lignin-rich solid. This analysis employed a central composite design of experiments. Furthermore, the phenolic compound content of the liquid phases and their antioxidant capacity were determined. Subsequently, a multi-objective optimization was conducted to maximize the removal of hemicellulose from CSS, producing a solid with high cellulose and lignin content while minimizing cellulose loss through solubilization in the liquid phases. The results of the multi-objective optimization demonstrated that a temperature of 185 °C, a reaction time of 65 min, and a liquid-solid ratio of 8:1 (w/w) were optimal for the removal of hemicellulose (88.12 %), while maintaining a solid fraction rich in cellulose and lignin. Furthermore, the resulting liquors contained xylooligosaccharides (17.73 % recovery) and phenolic compounds (18.91 mg GAE/g CSS) and showed antioxidant capacity (9.69 TEAC/g CSS). This research contributes to advancing sustainable agro-industrial waste valorization and the circular economy by investigating xylooligosaccharide and phenolic compound extraction as raw materials for other industries.