Microwave and ultrasound assisted synergistic extraction of aromatics from food and agro-waste using DES and NADES

The large demand for sustainable biomaterials has sparked the development of green extraction technologies in recovering valuable aromatic compounds from food and agro-wastes. Conventional solvent-based extraction is often inefficient and environmentally burdensome, creating an obstacle for cleaner, faster, and more selective technologies. Numerous studies have highlighted the efficiency and selectivity of these methods towards the extraction of diverse bioactive compounds like phenolics, flavonoids, antioxidants and pectin. Despite these advantages, the studies relating to the limited transition from laboratory to industrial application due to viscosity constraints, uneven energy distribution at larger scales, the insufficient exploration of standardized pilot-scale validation, and hybrid sequential synergy-based extraction parameters remain unexplored. This review addresses these problems by examining recent developments in DES-/NADES-based microwave and ultrasound assisted extraction of aromatic bio-actives from food and agricultural wastes, while elucidating how the solvent properties and energy-driven mechanisms control the efficiency of the extraction technique. It further evaluates process parameters, selectivity, scale-up challenges, sequential extraction techniques, parameters and identifies key gaps to direct the design of greener and more sustainable extraction systems. Overall, this work confirms that DES/NADES-assisted MAE and UAE considerably enhance extraction efficiency over conventional solvents and establishes solvent composition, water content, and energy matrix interaction as key design drivers. This review finally highlights clear strategic directions for development of scalable, selective and sustainable extraction systems for waste valorization by bridging fundamental mechanistic insights with performance outcomes.