Extraction is a method of extracting a chemical from a solution or mixture of solid substances. Conventional methods of extraction, for example, Soxhlet method, require the use of hazardous solvents, are time-consuming and cause degradation of
the extracted compounds. Green extraction is characterized by the speed, it gives a quantitative recovery of the extract and does not cause degradation of the components. It takes place at a lower energy consumption than conventional extraction. A number of novel alternatives to conventional extraction techniques have been proposed, including ultrasonic assisted extraction (UAE), supercritical fluid extraction (SFE), enzyme extraction or pulsed electric field. These techniques allow to reduce or eliminate the use of toxic solvents, improve process efficiency and extract quality. The temperature of the above-mentioned processes is low, which affects the behavior of temperature-sensitive substances. The widely used "green extraction" is SFE - extraction with supercritical fluid. The solvent is a supercritical fluid, most often carbon dioxide. Ultrasonic extraction is environmentally friendly, easy to use, versatile and relatively cheap compared to other innovative techniques. This technique can be used to extract, for example, polysaccharides, essential oils, proteins, peptides, dyes, pigments and bioactive
substances. Extraction with the use of pulsed electric field is used to extract mainly polyphenols and other bioactive components. Extraction with enzymes (mainly pectinases, cellulases and hemicellulases) is widely used in the food industry, eg for clarifying beer and juices. The extraction yield depends on the solvent system, temperature, enzyme function, substrate availability and pH.