Document Type

Article

Publication Date

6-1-2013

Abstract

Pulsed electric field (PEF) processing involves the application of pulses of voltage for less than 1 s to fluid products placed between 2 electrodes. The effect of mild PEF on beneficial characteristics of probiotic bacteria Lactobacillus acidophilus and Lactobacillus delbrueckii ssp. bulgaricus is not clearly understood. The objective of this study was to determine the influence of mild PEF conditions on acid tolerance, growth, and protease activity of Lb. acidophilus LA-K and Lactobacillus delbrueckii ssp. bulgaricus LB-12. A pilot plant PEF system (OSU-4M; The Ohio State University, Columbus) was used. The PEF treatments were positive square unipolar pulse width of 3. μs, pulse period of 0.5. s, electric field strength of 1. kV/cm, delay time of 20. μs, flow rate of 60. mL/min, and 40.5°C PEF treatment temperature. Both Lb. acidophilus LA-K and Lb. bulgaricus LB-12 subjected to mild PEF conditions were acid tolerant until the end of the 120. min of incubation, unlike the Lb. bulgaricus control, which was not acid tolerant after 30. min. The mild PEF-treated Lb. acidophilus LA-K and Lb. bulgaricus LB-12 reached the logarithmic phase of growth an hour earlier than the control. Mild PEF conditions studied significantly improved acid tolerance, exponential growth, and protease activity of both Lb. acidophilus LA-K and Lb. bulgaricus LB-12 compared with the control. The mild PEF conditions studied can be recommended for pretreating cultures to enhance these desirable attributes. © 2013 American Dairy Science Association.

Publication Source (Journal or Book title)

Journal of Dairy Science

First Page

3424

Last Page

3434

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