Abstract The effect of pulse duration on efficiency of disintegration of apple tissue by pulsed electric fields (PEF) was studied. The samples (26-mm diameter, 10-mm height) were treated by PEF at electric field strength E between 100 and 400 V/cm, pulse duration ti of 10, 100, 1,000 μs, interpulse duration Δt of 100 μs and different number of pulses n. Both the degree and the time evolution of tissue damage were quantified by electrical conductivity disintegration index Z and characteristic damage time τ, respectively. The samples exposed to the same PEF treatment time nti showed noticeably higher disintegration efficiency for larger pulse duration. The synergism of PEF and thermal treatment with temperature T (20–50 °C) was demonstrated. The Arrhenius dependence of τ(T) for PEF treatment at E=100 V/cm gave the decreasing activation energy W as a function of ti, (Q≈ 164 kJ/mol at ti=10 μs, Q≈109 kJ/mol at ti=100 μs and Q≈ 66 kJ/mol at ti=1,000 μs). Textural relaxation data supported the higher damage efficiency for longer pulse duration.
Pulse duration and efficiency of soft cellular tissue disintegration by pulsed electric fields
FERRARI, Giovanna;
2008-01-01
Abstract
Abstract The effect of pulse duration on efficiency of disintegration of apple tissue by pulsed electric fields (PEF) was studied. The samples (26-mm diameter, 10-mm height) were treated by PEF at electric field strength E between 100 and 400 V/cm, pulse duration ti of 10, 100, 1,000 μs, interpulse duration Δt of 100 μs and different number of pulses n. Both the degree and the time evolution of tissue damage were quantified by electrical conductivity disintegration index Z and characteristic damage time τ, respectively. The samples exposed to the same PEF treatment time nti showed noticeably higher disintegration efficiency for larger pulse duration. The synergism of PEF and thermal treatment with temperature T (20–50 °C) was demonstrated. The Arrhenius dependence of τ(T) for PEF treatment at E=100 V/cm gave the decreasing activation energy W as a function of ti, (Q≈ 164 kJ/mol at ti=10 μs, Q≈109 kJ/mol at ti=100 μs and Q≈ 66 kJ/mol at ti=1,000 μs). Textural relaxation data supported the higher damage efficiency for longer pulse duration.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
