Comparative evaluation of green extraction techniques for flavonoid recovery from peanut shells: Kinetic modeling, bioactivity assessment, and efficiency enhancement via sequential cellulase–ultrasound extraction

Peanut shells are a promising source of flavonoids; however, systematic comparative studies on extraction efficiency and the bioactivities of the resulting extracts remain limited. This study proposed that sequential cellulase-ultrasound extraction (SCUE) could enhance flavonoid recovery and bioactivity compared with individual green extraction methods and conventional techniques. Accordingly, cellulase-assisted extraction, ultrasound-assisted extraction, and SCUE were evaluated alongside Soxhlet extraction and hot ethanol extraction. Under optimal conditions (2% cellulase, 40% ultrasound amplitude, and 280 min extraction time), SCUE achieved the highest total flavonoid content (54.58 mg QE/g), quercetin (24.32 μg/g), and luteolin (148.61 μg/g). Peleg's model adequately described the extraction kinetics and confirmed the superior efficiency of SCUE. The SCUE extract also exhibited the strongest DPPH and acetylcholinesterase (AChE) inhibitory activities, with IC₅₀ values of 42.76 μg/mL and 66.27 μg/mL, respectively. These findings highlight SCUE as an effective green strategy for valorizing peanut shell waste into flavonoid-rich extracts with functional potential. • Sequential cellulase-ultrasound extraction (SCUE) enhanced flavonoid recovery. • SCUE-derived extract exhibited enhanced biological activities. • Peleg's model accurately described the kinetics of flavonoid extraction. • SCUE demonstrated superior efficiency compared with other extraction methods.