Pulsed Electric Field (PEF) Enhances Iron Uptake by the Yeast Saccharomyces cerevisiae

Abstract

The aim of the study was to investigate the influence of a pulsed electric field (PEF) on the level of iron ion accumulation in Saccharomyces cerevisiae cells and to select PEF conditions optimal for the highest uptake of this element. Iron ions were accumulated most efficiently when their source was iron (III) nitrate. When the following conditions of PEF treatment were used: voltage 1500 V, pulse width 10 μs, treatment time 20 min, and a number of pulses 1200, accumulation of iron ions in the cells from a 20 h-culture reached a maximum value of 48.01 mg/g dry mass. Application of the optimal PEF conditions thus increased iron accumulation in cells by 157% as compared to the sample enriched with iron without PEF. The second derivative of the FTIR spectra of iron-loaded and -unloaded yeast cells allowed us to determine the functional groups which may be involved in metal ion binding. The exposure of cells to PEF treatment only slightly influenced the biomass and cell viability. However, iron-enriched yeast (both with or without PEF) showed lower fermentative activity than a control sample. Thus obtained yeast biomass containing a high amount of incorporated iron may serve as an alternative to pharmacological supplementation in the state of iron deficiency.

The Use of Iron-Enriched Yeast for the Production of Flatbread

“…Additionally, this study showed that during gastric and intestinal digestion in vitro, yeasts are lysed and release most of the iron after 1–3 h of the process. In our previous studies, we have shown that iron ions are bound by functional groups present both in the cell wall and in the intracellular structures of yeast [ 30 ].…”

“…What is important, the panelist did not perceive a metallic after-taste which is a serious problem for products enriched with iron salts. The accumulation of iron in yeast may reduce unfavorable changes in taste in food products, since metal ions are associated with the cell organelles [ 30 ].…”

“…The culture was then incubated at 30 °C for 20 h. The culture P was exposed to PEF for 20 min at a pulse width of 10 μs, an electric field voltage of 1500 V, at a field frequency of 1 Hz using a laboratory electroporator (ECM 830, BTX Harvard Apparatus, Holliston, MA, USA)(except for control samples C1 and C2). Cultures were then incubated for 22 h. The biomass was centrifuged (10 min, 3000 rpm), the supernatant was discarded, and the cells were washed three times with deionized water [ 30 ] and freeze-dried (Labconco, Kansas City, MO, USA).…”

“…What is important, the pane did not perceive a metallic after-taste which is a serious problem for products enrich with iron salts. The accumulation of iron in yeast may reduce unfavorable changes in ta in food products, since metal ions are associated with the cell organelles [30]. C1-yeast without the addition of iron ions and without PEF; C2-yeast with the addition of iro ions and without PEF; P-yeast with the addition of iron ions and PEF.…”

Pulsed electric field treatment for the stimulation of microorganisms: Applications in food production

“…After 20 h of cultivation in a media containing iron salts, the cultures were treated with a PEF for 20 min at 3 kV•cm -1 with 1 200 pulses of 10 microseconds. Under these optimal conditions, the accumulation of iron ions (200 µg•mL -1 ) in the cells was 157% higher than the control (without the PEF) with a maximum value of 48.01 mg•g -1 dry mass (Nowosad et al 2021). Similar results were obtained when a S. cerevisiae biomass was exposed to a PEF treatment to improve the zinc accumulation in this https://doi.org/10.17221/78/2021-RAE yeast.…”