Effect of pulsed electrical fields on the structural properties that affect french fry texture during processing

Abstract

BackgroundThe french-fry manufacturing process via frozen partially-prepared fries involves a series of heat treatments in which the structural properties of a potato (starch structure, ion content, water content, cell wall architecture, and middle lamella) are substantially altered to produce a french fry with a crispy crust and a mealy core. In addition to the traditional processing steps (washing and sorting, peeling, cutting, blanching, dipping, pre-drying, par-frying and freezing), short pulses of high voltage (pulsed electric field, PEF) are now often applied to potatoes before they are cut into french-fry strips. The final texture is the result of not only the effects of heat and PEF treatments on the structural properties of the potato tuber, but also the effects of interactions between these treatments. Scope and approachThis paper explains the main processes involved during manufacturing of french fries and their effect on the tuber structure properties responsible for french fry texture (changes in starch structure, cell wall architecture, water and oil content) currently available. It summarizes the research on the effect of PEF on those structural properties, their relevance, and applicability and highlights future research needs. Key findings and conclusionsThe effect of heat treatments (steam peeling, blanching, pre drying, par frying) and freezing on the structural properties that affect texture have been widely studied. Manufacturers have adopted a new procedure, PEF treatment, about which little is known about the effect on the structural properties that affect texture and the synergistic interaction effects with the other manufacturing steps of french fry production. There is a need for investigation of these changes and the mechanistic reasons for any effects on final texture.