Synthesis and application of Natural Deep Eutectic Solvents (NADESs) for Upcycling Horticulture Residues

Upcycling horticulture residues offers a sustainable solution to reduce environmental impact, maximize resource utilization, mitigate climate change, and contribute to the circular economy. We synthesized and characterized fourteen natural deep eutectic solvents (NADESs) and applied them to upcycle horticulture residues offering an innovative valorization approach. With initial many factors at a time (MFAT) screening followed by a rotatable central composite response surface methodology (RCCRSM) for optimization, quadratic models fitted the response data for all the synthesized NADESs given: TPC (R2 = 0.984, p < 0.0001), TFC (R2= 0.9999, p < 0.0001), and AA- CUPRAC (R2 = 0.918, p < 0.0001), FRAP (R2 =1.000, P < 0001), and DPPH (R2 = 0.9992, p < 0.0001). Ultrasound temperature 45°C, extraction time 5 min, solvent volume 25 mL, and solvent concentration 90% (v/v) were considered the optimal conditions for maximum desirability (0.9936) of TPC yield; 30°C, 5 min, 25 ml, and 90% (v/v) for maximum desirability (0.9003) for TFC and CUPRAC with maximum desirability (1.00). The maximum desirability for FRAP was (0.9605) at conditions of 45°C, 25 min, 25 ml, and 50%, while DPPH with maximum desirability of (0.9313) had 50°C, 15 min, 15 mL, and 70% (v/v) as the optimized conditions respectively.