ABSTRACT
In general, the extraction of polyphenols from plants has been based on the use of organic solvents, at boiling point temperatures or lower, and atmospheric pressure. Organic solvents, such as methanol, ethanol, and acetone, and their combinations with different proportions of water are commonly used (Dai and Mumper, 2010; Ignat et al., 2011; Shi et al., 2005). The conventional extraction methods imply heating, boiling, or reuxing the solvent for long periods of time to extract natural phenolic compounds. These conventional extraction methods could present several disadvantages, including the loss of polyphenols due to ionization, hydrolysis, and oxidation; these methods also use large amounts of questionable solvents, which are time consuming and expensive, in addition to the subsequent solvent-recovering processes (Deyama et al., 1987; Herrero et al., 2006; Li et al., 2005; Ohnishi et al., 1994;
4.1 Introduction .................................................................................................... 83 4.2 Extraction Enhancement by Rising Temperature and Pressure .....................85
