Chapter 19 - Adsorption and Ion Exchange for the Recovery and Fractionation of Polyphenols: Principles and Applications

Abstract

Adsorption and ion exchange have been employed for thousands of years. Man has exploited the potential of this technology in various application areas, ranging from water and wastewater treatment to food processing and medicinal applications. Together with the development of more sophisticated synthetic polymers exhibiting tailor-made functional properties, the application of resin adsorption and ion exchange technology has been significantly promoted. Nowadays, synthetic resins form an integral part of many food processing units, mainly for the removal of unwanted compounds, for example, Maillard reaction products or polyphenols responsible for adverse sensations, such as bitterness, astringency, or brownish colors. On the contrary, these technologies are now also increasingly used for the enrichment and purification of phenolic compounds as putative health-beneficial plant constituents. The byproducts of plant food processing, which are still very rich in phenolic valuables, are attractive sources for this type of recovery process, thus allowing additional valorization of such “waste” materials and contributing to sustainable food production. In this context, resin-based technologies play a dominant role in establishing innovative valorization strategies aiming at the production of high-quality foods and the recovery of techno- and biofunctional phenolic components. This chapter provides an overview of the most common resin types used for such purposes, particularly focusing on research studies performed in recent years to systematically advance this technology and improve practical applications. Furthermore, resin-based industrial processes already put into practice are exemplified.