Recent advances in the extraction of polyphenols from eggplant and their application in foods

The extraction of bioactive compounds from plant materials, such as eggplant, has been commonly carried out using classical extraction processes, based on solid-liquid extraction such as hydrodistillation and Soxhlet extraction. However, a series of disadvantages of these methods, such as long operating times or excessive organic solvents consumption, have caused the necessity to gradually replace them by other modern extraction technologies. Emerging extraction technologies has advantages over conventional extraction methods and are being increasingly used for the recovery of bioactive compounds from plants, such as eggplant, rich in phenolic compounds with antioxidant activity. This article presents the main polyphenols in eggplant and reviews the latest advances in their extraction. In addition, the incorporation of eggplant in the formulation of functional foods is also described. Ultrasound-assisted technology (UAE) is a suitable technology for the recovery of very abundant heat-sensitive compounds in eggplant, such as anthocyanins and phenolic acids. In addition, these compounds present several bio-activities and health-related properties so their incorporation into the preparation of different foods is a good strategy to produce functional foods.