INACTIVATION of SACCHAROMYCES CEREVISIAE IN APPLE JUICE BY SQUARE-WAVE and EXPONENTIAL-DECAY PULSED ELECTRIC FIELDS |
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Authors: | QINGHUA ZHANG,ADELMO MONSALVE-GONZÁ LEZ,BAI-LIN QIN,GUSTAVO V. BARBOSA-CÁ NOVAS,BARRY G. SWANSON |
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Affiliation: | Department of Biological Systems Engineering;Department of Food Science and Human Nutrition Washington State University, Pullman, WA 99164-6120 |
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Abstract: | With equivalent electrical energy input, inactivation of microorganisms by pulsed electric fields depends on pulse waveform. Exponential-decay and square-wave pulsed electric fields were selected to treat Saccharomyces cerevisiae suspended in apple juice. A parallel-plate static treatment chamber with 25 ml volume and 0.95 cm electrode gap was used. Peak electric field and pulse electric energy input were 12 kV/cm and 260 Joules per pulse for both waveforms. Both waveforms were found effective in the microbial inactivation. However, inactivation of S. cerevisiae treated with square-wave pulses was greater than yeast treated with exponential-decay pulses. For the purpose of food pasteurization, square-wave pulsed electric fields may result in significant energy savings compared to exponential-decay pulses. |
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