Acid Tolerance of Lactobacillus acidophilus LA-K as Influenced by Various Pulsed Electric Field Conditions

摘要

Pulsed electric field (PEF) processing involves the application of pulses of voltage for less than one second to fluid foods placed between two electrodes. Lactobacillus acidophilus is an important probiotic bacterium used for the production of fermented dairy products. Acid tolerance is an important probiotic characteristic. The influence of PEF on acid tolerance of Lactobacillus acidophilus is not known. Objective of this study was to elucidate the influence of certain PEF conditions on the acid tolerance of Lactobacillus acidophilus LA-K. Freshly thawed Lactobacillus acidophilus LA-K was suspended in sterile peptone 0.1% w/v distilled water and treated in a pilot plant PEF system. The treatments were pulse width (3, 6 and 9 μs), pulse period (10,000; 20,000 and 30,000 μs) and voltage (5, 15 and 25 kV/cm). Control was run through PEF system at 60 mL/min without receiving any pulsed electric field condition. Data were analyzed using the PROC GLM of the Statistical Analysis Systems (SAS). Differences of least square means were used to determine significant differences at P Lactobacillus acidophilus LA-K lowered by increasing pulse widths and voltages but lowering pulse periods.