The effect of pulsed electric field treatment on immersion freezing, thawing and selected properties of apple tissue

The aim of this work was to investigate the effect of pulsed electric field on kinetics of immersion freezing and thawing, and quality of freeze-thawed apple. The time of each freezing and thawing stage was distinguished. The quality of freeze-thawed products was assessed by mass loss, textural properties and color change. PEF application resulted in 3.5-17.2% total freezing time reduction. The phase transition stage during freezing was up to 33% shorter in comparison with the untreated samples. The total thawing time was reduced by 71.5%. Maximal mass loss (8.9%) was noticed for apples treated by 50 pulses at 5 kV/cm. However, the samples treated by 10 pulses at 3 kV/cm were characterized by lower mass loss (1.6%) as compared to the untreated samples (2.3%). PEF treatment changed the color of samples (ΔE = 5.74-19.58). The results of the research indicate that it is possible to modify freeze-thawed products' texture by PEF application.