Ultrasonication - A green technology extraction technique for spices: A review

Spices are rich source of naturally occurring bioactives and are used in different food applications. Major spice bioactives include essential oils, oleoresins, polysaccharides, phenolics, alkaloids, vitamins, and carotenoids. Conventional extraction of these bioactives has been associated with a high requirement of time, solvent, and energy which diminishes the application. This review discusses and summaries the recent findings on UAE for extraction of bioactives from spices. The concepts, mechanisms, factors affecting the sonication process, and their application in the extraction of spice bioactives are reviewed. The integration of UAE with other emerging technologies, mainly microwave-assisted and supercritical fluid (CO2) assisted extraction methods in the field of spice bioactives extraction are also explored. A comparison of different optimization and modeling methods used for UAE of spices are discussed and enunciate the gaps and possible future trend. Acoustic cavitation generated during ultrasound treatment produces shock waves, microjets, shear force, and sonochemical reactions causing plant cell erosion and pore formation. It enhances mass transfer paving way for application of green solvents such as water. Further the Two-site kinetic model and Peleg's model are most versatile in explaining the UAE of bioactives from spices. Maximized recovery of bioactives, could be attained by selecting combination of technologies and process parameters for improved energy efficiency reduced time and energy consumption.