Solvent-free microwave-assisted extraction: Enhancing bioactive molecules retention in citrus post-distillation...

While numerous studies have focused on improving essential oils extraction, the post-distillation residue has received little attention, despite its richness in biomolecules. Therefore, this study aims to assess the interactive effects of solvent-free microwave-assisted extraction power and time on the non-volatile profile and bioactivities of Citrus limon post-distillation residue. Results showed that the yield of extracts increased from 17.1% before distillation to 25.12-38.6% after distillation. However, flavonoids and sugars decreased from 42.17 mg QE/g and 510.41 mg GE/g before distillation to 18.93-38.45 mg QE/g and 123.12-400.62 mg GE/g after distillation, respectively. Furthermore, minerals, polyphenols, and biological properties varied depending on distillation conditions. SFME showed variable optimal conditions depending on the target compound, with distillation at 800 W/100 min being the most favorable for many of the measured parameters. These findings investigated the overall changes in biomass composition after distillation and support future studies seeking to explore the entire biomass in biorefinery processes.