Recovery of antioxidants from agro-food products and by-products by integrated membrane processes

Antioxidants play a vital role in both food and chemical systems as well as in the human body to reduce oxidative processes. These molecules are generally present in complex matrices and have to be separated from the feedstock in order to increase their purity and antioxidant capacity. Membrane technologies are the main processes used at large scale for the recovery, separation and purification of antioxidant compounds from different sources. The basic properties of these processes make them ideal for the treatment of both food products and by-products; high selectivity, minimization of thermal damage, low energy consumption, modularity and easy scale-up, no phase change and use of chemical additives are typical advantages over conventional separation technologies. Investigated applications of membrane unit operations and integrated membrane systems in specific areas of the agro-food production are presented and discussed, highlighting their potential with respect to the separation, concentration and purification of antioxidant compounds from products and by-products. Conceptual designs of integrated membrane processes are proposed on the basis of membrane unit operations investigated on laboratory scale and optimized in terms of membrane materials, pore-sizes, and fluid-dynamic conditions in order to improve their productivity and selectivity towards compounds of interest. The proposed applications represent a flexible approach to valorize agro-food waste streams, as alternative to their disposal, and to improve the quality of agro-food productions within the logic of the process intensification strategy.