Table 1.
Effect of Pulse Electric Field Technology on Food Enzymes. (Taken and modified from (Bayindrili, 2010) [10].
| Enzyme | Enzyme and buffer solution/medium | Processing condition | Enzymes stability |
|---|---|---|---|
| Lipoxygenase (LOX) | Green bean juice | Mono polar mode; electric field strength: 2.5–20 kV/cm; pulse width: 1 μs; pulse numbers: 100 to 400; pulse frequency: 1 Hz | No inactivation |
| Soymilk | Bipolar mode; electric field strength: 20–42 kV/cm; pulse width: 1–5 μs; treatment time for up to 1036 μsc | Irreversible inactivation Max. inactivation: 88% treated at 42 kV/cm for 1036 μs with 400 Hz of pulse frequency and 2 μs of pulse width at 25 °C | |
| Soymilk | electric field strength: 20, 30, and 40 kV/cm; treatment time: 25, 50, and 100 μs; pre-treatment heating temperatures: 23, 35, and 50 °C | Irreversible inactivation Max. inactivation: 84.5% at 40 kV/cm for 100 μs with preheating at 50 °C | |
| Tomato juice | bipolar mode; 4 co-field tubular treatment chambers; electric field strength: 0–35 kV/cm; treatment time: 20–70 ms; pulse width: 3 μs; PEF treatment temperature: 10–50 °C; flow rate: 1 mL/s; pulse delay time: 20 μs | Irreversible inactivation Max. inactivation: 80% treated at 35 kV/cm for 50 or 60 ms at 30 °C. | |
| Tomato juice | bipolar mode; 6 co-field tubular treatment chambers; electric field strength: 40 kV/cm; treatment time: 57 μs; pulse width: 2 μs; temperature before PEF treatment: 45 °C (temperature increase of 8 °C during treatment) | Irreversible inactivation Max. inactivation: 54% | |
| Papain | Commercial purified papaya papain initially activated by reducing agents (cysteine 20 mM and DTT 5 mM) and diluted in 1 mM EDTA | electrical field strength: 20, 30, 40, and 50 kV/cm; pulse width: 4 μs; continuous system; flow rate: 0.77 ml/s; pulse numbers: up to 1500 | Irreversible inactivation Max inactivation: up to 40% immediately after PEF treatment at 50 kV/cm and 500 pulses |
| Pectinmethylesterase (PME) | Commercial purified orange PME, details on medium and enzyme concentration not completely described | Exponential decay pulse; coaxial and parallel-plane treatment chamber, electric field strength: 5–25 kV/cm; treatment time: 0.5–15 μs; pulse frequency: 1 Hz, pulse numbers: 207 to 1449 | Irreversible inactivation Max. inactivation: 17% and 16.46% in coaxial cylinder and parallel-plane chamber, respectively, treated at 207 pulses of 25 kV/cm |
| Partiallya purified banana, carrot, orange and tomato PME dissolved in Tris buffer (20 mM; pH 7.0) | electric field strength: 13.2 and 19.1 kV/cm; treatment time: 1.6 ms; pulse frequency: 0.5 or 5 Hz | Irreversible inactivation Max. inactivation: 45% (banana), 83% (carrot), 87% (orange and tomato) | |
| Pectinex 100 Lr (Novo Nordisk Ferment, Neumatt, Switzerland) in distilled water at 5% mass fraction; electrical conductivity: 11.48 S/m, pH 4.73 | Square wave pulse; pulse width: 40 μs; electric field strength: 5–24 kV/cm; total treatment time: 16 ms; pulse frequency: 0.5 or 5 Hz | Irreversible inactivation Max. inactivation: approximately 95–98% treated at 5 kV/cm for 16 ms; 12 kV/cm for 8–12 ms; 20 kV/cm for 6–8 ms and 24 kV/cm for 4 ms | |
| Desalted pectinex 100 Lr (Novo Nordisk Ferment, Neumatt, Switzerland) diluted in bi-distilled water (1:5 v/v); pH 4.6 | Exponential decay pulse; monopolar mode; electric field strength: 19, 25, 30, 33, 36 and 38 kV/cm; inlet temperature: 4 °C; pulse numbers: 10 to 100 | Irreversible inactivation Max. inactivation: approximately 86.8% treated at 38 kV/cm for 340 μs | |
| Grape fruit juice | Monopolar mode, electric field strength: 20, 30, and 40 kV/cm; preheating at 23, 35, and 50 °C; 15 Hz; pulse width: 1 μs; treatment time: 25, 50, 75, and 100 μs | Irreversible inactivation Max. inactivation: 96.8% obtained using a combination of preheating to 50 °C, and a PEF treatment time of 100 μs at 40 kV/cm | |
| (Valencia) orange juice | monopolar mode; inlet temperature <40 °C; pulse width: 1.4 μs, pulse frequency: 600 Hz; electric field pulse: 20–35 kV/cm; treatment time 59 μs | Irreversible inactivation Max. inactivation: 90% treated at 35 kV/cm for 59 μs | |
| (Valencia) orange juice | Six co-field tubular chambers (diameter 0.635 cm); electric field pulse: 35 kV/cm; treatment time 59 μs | Irreversible inactivation Max. inactivation: 88% | |
| (Valencia) orange juice | bipolar mode; inlet temperature 10–50 °C; pulse frequency: 700 Hz; electric field pulse: up to 35 kV/cm; treatment time up to 250 ms | Irreversible inactivation Max. inactivation: 90% treated at 25 kV/cm and 50 °C for 250 ms | |
| Orange juice | monopolar pulse; 1000 pulses; pulse width: 1 μs; pulse frequency: 1 or 2 Hz; electric field strength: up to 35 kV/cm | no inactivation but increase in activity probably due to cell permeabilization and release of intracellular pectinmethylesterase | |
| (Navelina) orange juice | bipolar mode; temperature <40 °C; pulse width: 4 μs, pulse frequency: 200 Hz; electric field pulse: 35 kV/cm; treatment time 1 ms; energy input of 5390 MJ/m3 | Irreversible inactivation Max. inactivation: 81.6% | |
| Orange juice | mono- or bipolar mode; electric field strength: 5, 15, 25, 30, and 35 kV/cm; treatment time: 100, 300, 600, 1000, and 1500 μs; pulse width: 4 μs; pulse frequency: 200 Hz. | Irreversible inactivation Max. inactivation: 80% treated at 35 kV/cm for 1500 μs with 4 μs bipolar pulses at 200 Hz without exceeding 37.5 °C | |
| (Valencia) orange juice-milk beverage | bipolar mode; six co-field chambers; pulse width: 2.5 μs; treatment time: 50 μs; electric field strength: 30 kV/cm | Irreversible inactivation Max. inactivation: 90% |