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Microalgae cell membrane permeabilization has been studied, for Chlorella sp., in a continuous 6-L prototype for different field strengths in order to minimize the specific energy supplied and the treatment time. Regarding lower electrical field strength values, the optimal results were achieved at 10 kV/cm, 200 Hz, and 5-µs per pulse, corresponding to an energy delivered of 9 kJ/kg of culture, with 97% of cells affected after 300 ms of treatment time. Regarding energy delivered per kilogram of Biomass, the best result was 2.7 MJ/kg of biomass with 95% of cells affected after 300 ms of treatment time and was achieved at 15 kV/cm, 200 Hz, and 5-µs per pulse. Pulsed electric field effect was quantified by flow cytometry using propidium iodide as a viability stain. The influence of conductivity and cell concentration was also analyzed. The final goal was to evaluate the use of this technology in terms of increasing bioaccessibility of bioactive compounds present in microalgae for food and feed purposes. These results, obtained only for chlorophyll a and b, did not show any beneficial effect of this technology against nontreated biomass.Index Terms-Bioaccessibility, Chlorella, electroporation, microalgae, pulsed electric field (PEF).

The effect of monopolar and bipolar shaped pulses in additional yield of apple juice extraction is evaluated. The applied electric field strength, pulsewidth, and number of pulses are assessed for both pulse types, and divergences are analyzed. Variation of electric field strength is ranged from 100 to 1300 V/cm, pulsewidth from 20 to 300 μs, and the number of pulses from 10 to 200, at a frequency of 200 Hz. Two pulse trains separated by 1 s are applied to apple cubes. Results are plotted against reference untreated samples for all assays. Specific energy consumption is calculated for each experiment as well as qualitative indicators for apple juice of total soluble dry matter and absorbance at 390-nm wavelength. Bipolar pulses demonstrated higher efficiency, and specific energetic consumption has a threshold where higher inputs of energy do not result in higher juice extraction when electric field variation is applied. Total soluble dry matter and absorbance results do not illustrate significant differences between application of monopolar and bipolar pulses, but all values are inside the limits proposed for apple juice intended for human consumption.

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