Microwave-Assisted Glycerol-Based Extraction of Bioactive Compounds from Defatted Hass Avocado Cake: Process Optimization, Chemical Characterization, and Sustainability Assessment

Abstract

Avocado processing generates substantial agro-industrial residues with potential as sources of bioactive compounds. This study investigated defatted cake obtained from continuous-press oil extraction of Hass avocado pulp and peel as a feedstock for bioactive recovery. Microwave-assisted extraction using glycerol as a solvent was optimized through experimental design by varying glycerol concentration (40–90%), temperature (70–170 °C), and extraction time (7–23 min). Optimal conditions (170 °C, 70% glycerol, 7 min) produced significantly higher total phenolic content and antioxidant capacity than conventional extraction (p < 0.05). UPLC-HRMS/MS analysis enabled the putative identification of 55 compounds. Toxicity assessment using Galleria mellonella indicated low toxicity at 1033 mg GAE L–1. Sustainability evaluation using the Path2Green metric yielded a score of 0.595, demonstrating favorable environmental performance. These results highlight microwave-assisted glycerol-based extraction as an efficient and sustainable strategy for avocado byproduct valorization.