Influence of Pulsed Electric Field on Accumulation of Calcium in Lactobacillus rhamnosus B 442

Abstract

Calcium is an element that performs many important functions in the human body. A study was conducted on the use of a pulsed electric field (PEF) to enrich cells of Lactobacillus rhamnosus B 442 in calcium ions. The highest concentration of calcium ions in bacterial cells (7.30 mg/g d.m.) was obtained at ion concentration of 200 µg/ml of medium and with the use of the following PEF parameters: field strength 3.0 kV/cm, exposure time 10 min, pulse width 75 ms and 20 h of culturing after which bacteria were treated with the field. Cell biomass varied in the range from 0.09 g/g d.m. to 0.252 g/g d.m., and the total number of bacteria ranged from 10 1 0 CFU/ml to 10 1 2 CFU/ml. Microscope photographs prove that calcium ions were situated within the cells of the bacteria, and electroporation contributed to an increase in the effectiveness of the ion bioaccumulation process. Samples containing calcium and subjected to electroporation displayed intensive fluorescence. The significance of this research was the possibility of using probiotic bacteria enriched with calcium ions for the production of functional food in subsequent studies.

The application of PEF technology in food processing and human nutrition

“…The maximum content of zinc ions from cells was 2.85 mg Zn 2+ /g d.m. PEF did not reduce bacterial viability or biomass Góral et al ( 2019a , b ) …”

“…The higher total number of microorganisms was noted in the ice cream than in the starter cultures, however, the viability of these bacteria was lower than in the control samples (Góral et al 2018 ). Góral et al ( 2019a , b ) used PEF for enhancing bioaccumulation of calcium and zinc in the cells of Lactobacillus rhamnosus B 442. The highest bioaccumulation of zinc was observed when the following PEF parameters were applied: field strength 3 kV/cm, pulse width 20 μs and electroporation time of 20 min.…”