Effects of preliminary treatment by pulsed electric fields and convective air-drying on characteristics of fried potato

Effects of pulsed electric fields (PEF) and preliminary convective air (CA) drying on the water loss and oil uptake during frying of potato disks have been investigated. The PEF treatment was done using a monopolar generator with electric field strength of 600 V/cm and pulsed protocol that allows obtaining the high level of electroporation. The different protocols of drying (for t(d) = 500, 1000 and 2000 s, at T = 50 degrees C) and frying (for t(f) = 0-600 s at T = 130 degrees C) were tested. The frying kinetics was described using extended exponential function. A mean frying time t(f) decreased with increasing of time of preliminary drying t(d). The PEF treatment also resulted in decreasing of t(d). For example, with preliminary CA drying during t(d) >= 500 s, the oil uptake after frying (t(f) = 600 s) was significantly smaller in the PEF treated potato (approximate to 0.30 g/g DM) than in untreated potatoes (approximate to 0.47 g/g DM). Combined preliminary PEF-treatments and CA-assisted dehydration significantly affected the frying time, the oil uptake and texture of samples. They can lead to the formation of a denser and less oil penetrable skin on the potato surface during the frying. Industrial relevance: Application of PEF allows acceleration of CA drying of potato. The CA drying has positive effect on characteristics of fried products. Combined preliminary PEF-treatments and CA-assisted dehydration have favorable impacts on oil uptake and texture changes. Such processing could decrease process time, improve qualitative characteristics and safety of fried potato.