The use of PEF technology for improving mass transfer phenomena in traditional unit operations of food industry

Several unit operations of the food industry are based on mass transfer phenomena which promote the extraction of a given substance of interest (fruit juices, sugars, colorants, antioxidants, etc.) removing water from foods (drying), or introducing a given substance into the food matrix (osmotic dehydration, salting, or curing). Interestingly, the recovery of valuable compounds (natural colorants or nutraceuticals) from food wastes and by-products, which have been matter of concern by the agri-food industry due to their environmental impact, is gaining increasing interest in the last years. In all these cases it is necessary to improve mass transfer through food tissues by means of the permeabilization of the cell membranes which represents the main factor controlling the mass transfer rate. Pretreatments that modify the permeability of the cell membranes, such as grinding, heating, or enzymatic treatment, may significantly enhance the mass transfer. However, these techniques may require a significant amount of energy and can cause losses of valuable food compounds. Moreover, chemical methods may require the application of unsafe organic solvents, and enzymes. Recently, the interest in electroporation or PEF technology has considerably grown, as it also offers the possibility different milder and more efficient non-thermal alternatives to the traditional processing methods of the food industry requiring the disintegration of cell membranes. The purpose of this work is to give an overwiev of the state of the art of application of PEF for improving mass transfer in the food industry. Finally, the industrial feasibility of PEF technology, its integration in the processing lines and the cost estimation of the treatments required to permeabilize the cell membranes are discussed