Process optimization of bioactive compounds extraction from bee bread using deep eutectic solvents: a response surface methodology approach

Abstract The growing demand for sustainable extraction technologies has prompted the exploration of deep eutectic solvents (DESs) as promising alternatives for the recovery of bioactive compounds. This study aimed to optimize the extraction conditions of bioactive compounds from bee bread using choline chloride–propylene glycol-based DESs via ultrasonic-assisted extraction and response surface methodology (RSM). The experimental design was established using the Box–Behnken model with three independent variables: extraction time (15–45 min), temperature (30–70 °C), and propylene glycol (PG) molar ratio (1–2 M). The extraction efficiency was evaluated in terms of total flavonoid content, antioxidant capacities (determined by ABTS, DPPH, and FRAP analyses), and condensed tannin content. At the optimum point, the DES system yielded a total flavonoid content (TFC) of 19.49 ± 0.03 mg QE g − 1 DW, and antioxidant activity values of 8.57 ± 0.06 mg TEAC g − 1 DW (ABTS), 11.46 ± 0.02 mg TEAC g − 1 DW (DPPH), and 0.23 ± 0.00 mg FeSO 4 g − 1 DW (FRAP). The condensed tannin content (CTC) reached 1.49 ± 0.01 mg CE g − 1 DW under these conditions. Statistical analysis demonstrated significant effects of all extraction parameters ( p < 0.05). The developed regression models showed strong predictive capability ( p = 0.0001 or p < 0.0001, and lack-of-fit > 0.05) and model adequacy (R² > 0.84). These results highlighted the effectiveness of DESs in maximizing the extraction of bioactive compounds from bee bread under optimized conditions (33.22 min, 70 °C, 1.56 M PG). DESs offer environmentally friendly and viable alternatives to organic solvents for the extraction of bioactive compounds from apicultural matrices due to their low cost, biodegradability, and high efficiency.