Microwave- and ultrasound-assisted extraction of biocompounds from poblano chilli waste

Green extraction techniques like microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) offer benefits due to their reduced environmental impact, lower consumption of organic solvents, energy, time and enhanced efficiency. This research aimed to extract phenolic compounds from unroasted poblano chilli (UPC) and roasted poblano chilli (RPC) Capsicum annum cv. ‘Poblano’ waste using UAE and MAE. Operational parameters were optimized by response surface methodology (RSM) to maximize the extraction of phenolics and evaluate the antioxidant capacity of the extracts. The highest yields were obtained using UAE in RPC (1.76 ± 0.14 mg GAE/gDW), followed by MAE in RPC (1.48 ± 0.05 mg GAE/gDW). HPLC analysis confirmed the higher concentration of gallic acid in the UAE-RPC extracts. No significant differences (p < 0.05) in extraction yield were found between the techniques for UPC. RPC extracts showed higher antioxidant capacity (80.56 ± 2.26 and 43.91 ± 3.78 μmol TE/gDW) compared to unroasted ones (13.72 ± 0.95 and 15.04 ± 1.44 μmol TE/gDW), regardless of the extraction method. RSM analysis indicated that UAE was the most effective treatment (60 °C, 5 min and 2% of sample concentration). A bibliometric analysis revealed opportunities for further research and utilization of poblano chili waste as a functional ingredient. Both extraction techniques were effective, highlighting poblano chili waste as a source of antioxidant phenolic compounds.