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Effect of moderate electric field pulses on the diffusion coefficient of soluble substances from apple slices
Author(s) -
Jemai Abdel Basset,
Vorobiev Eugene
Publication year - 2002
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1046/j.1365-2621.2002.00516.x
Subject(s) - activation energy , analytical chemistry (journal) , diffusion , arrhenius equation , electric field , chemistry , mole , kinetic energy , thermal diffusivity , arrhenius plot , materials science , thermodynamics , chromatography , organic chemistry , physics , quantum mechanics
The effects of a moderate electric field pulse (MEFP) on the diffusion coefficient of soluble substances from apple slices have been investigated. The apparent diffusion coefficient, D , was studied for both thermally and electrically treated samples. For thermally treated samples, the variation of D th as a function of temperature followed an Arrhenius type kinetic with two diffusion regimes: (i) without thermal pretreatment ( E a ≈ 28 kJ mole –1 ) and (ii) after plasmolysis pretreatment ( E a ≈ 13 kJ mole –1 ). In the case of electrically treated samples, only one regime was observed, with an intermediate activation energy ( E a ≈ 20 kJ mole –1 ). Furthermore, it was found that an electrical pretreatment with moderate temperature elevation (10–15 °C) combined with a low thermal treatment, significantly enhanced the diffusion coefficient ( D el ) compared with reference values. For instance, after a standard MEFP treatment (500 V cm –1 , 1000 pulses, 100 μs duration) D el was 3.9 × 10 –10 m 2 s –1 at 20 °C compared with reference values of 2.5 and 4.4 × 10 –10 m 2 s –1 for untreated and denatured samples, respectively, and 13.4 × 10 –10 m 2 s –1 at 75 °C compared with 10.2 × 10 –10 m 2 s –1 for thermally denatured samples. This indicates that an electrical treatment has a greater effect on the structure and permeability of apple tissue than thermal treatment.