Effect of ultrasound on the survival of Saccharomyces cerevisiae: Influence of temperature, pH and amplitude
The resistance of Saccharomyces cerevisiae cells to the action of ultrasound (20 kHz, wave amplitude in the range 71-110 μm) was analyzed at 35, 45 and 55°C in Sabouraud broth at pH 3.0 and 5.6. The inactivation rate where a first-order kinetic was observed exhibited D values between 0.5 and 31 min....
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| Autores principales: | , , |
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_14668564_v2_n1_p31_Guerrero |
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| Sumario: | The resistance of Saccharomyces cerevisiae cells to the action of ultrasound (20 kHz, wave amplitude in the range 71-110 μm) was analyzed at 35, 45 and 55°C in Sabouraud broth at pH 3.0 and 5.6. The inactivation rate where a first-order kinetic was observed exhibited D values between 0.5 and 31 min. The resistance of the yeast decreased as ultrasonic wave amplitude increased, with the z values for this effect ranging between 128 and 323 μm. In the pH range investigated, the reduction of pH did not affect ultrasound yeast sensitivity except for experiments performed at 71.4 μm wave amplitude and 45°C. At moderate temperatures, decimal reduction time values were reduced by the simultaneous effect of ultrasound but at 55°C, no advantages were observed by adding sonication. Structural studies performed in cells sonicated at 45°C and 95.2 μm of wave amplitude indicated the treatment provoked puncturing of cell walls with leakage of content as well as damage at subcellular level. However, when ultrasound was applied at 55°C, no structural differences were appreciated between sonicated cells and only heat-treated cells. © 2001 Elsevier Science Ltd. |
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