Use of a Pulsed Electric Field to Improve the Biogas Potential of Maize Silage

Some types of biomass require great inputs to guarantee high conversion rates to methane. The complex structure of lignocellulose impedes its penetration by cellulolytic enzymes, as a result of which a longer retention time is necessary to increase the availability of nutrients. To use the full biogas potential of lignocellulosic substrates, a substrate pretreatment is necessary before the proper methane fermentation. This article discusses the impact of the pretreatment of maize silage with a pulsed electric field on biogas productivity. The experiment showed a slight decrease in cellulose, hemicellulose and lignin content in the substrate following pretreatment with a pulsed electric field, which resulted in a higher carbohydrate content in the liquid substrate fraction. The highest biogas production output was obtained for the pretreated sample at the retention time of 180 s for 751.97 mL/g volatile solids (VS), which was approximately 14% higher than for the control sample. The methane production rate for the control sample was 401.83 mL CH4/g VS, and for the sample following disintegration it was 465.62 mL CH4/g VS. The study found that pretreatment of maize silage with a pulsed electric field increased the biogas potential.

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The Impact of Pulsed Electric Field on the Extraction of Bioactive Compounds from Beetroot

Foods ◽

10.3390/foods8070244 ◽

2019 ◽

Vol 8 (7) ◽

pp. 244 ◽

Cited By ~ 12

Author(s):

Malgorzata Nowacka ◽

Silvia Tappi ◽

Artur Wiktor ◽

Katarzyna Rybak ◽

Agnieszka Miszczykowska ◽

...

Keyword(s):

Electric Field ◽

Bioactive Compounds ◽

Control Sample ◽

Pulsed Electric Field ◽

Pulse Number ◽

Cell Membrane Permeability ◽

Mineral Salts ◽

Treated Sample ◽

Pre Treatment ◽

The Impact

Beetroot is a root vegetable rich in different bioactive components, such as vitamins, minerals, phenolics, carotenoids, nitrate, ascorbic acids, and betalains, that can have a positive effect on human health. The aim of this work was to study the influence of the pulsed electric field (PEF) at different electric field strengths (4.38 and 6.25 kV/cm), pulse number 10–30, and energy input 0–12.5 kJ/kg as a pretreatment method on the extraction of betalains from beetroot. The obtained results showed that the application of PEF pre-treatment significantly (p < 0.05) influenced the efficiency of extraction of bioactive compounds from beetroot. The highest increase in the content of betalain compounds in the red beet’s extract (betanin by 329%, vulgaxanthin by 244%, compared to the control sample), was noted for 20 pulses of electric field at 4.38 kV/cm of strength. Treatment of the plant material with a PEF also resulted in an increase in the electrical conductivity compared to the non-treated sample due to the increase in cell membrane permeability, which was associated with leakage of substances able to conduct electricity, including mineral salts, into the intercellular space.

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

Biomolecules ◽

10.3390/biom11060850 ◽

2021 ◽

Vol 11 (6) ◽

pp. 850

Author(s):

Karolina Nowosad ◽

Monika Sujka ◽

Urszula Pankiewicz ◽

Damijan Miklavčič ◽

Marta Arczewska

Keyword(s):

Saccharomyces Cerevisiae ◽

Electric Field ◽

Metal Ion ◽

Treatment Time ◽

Control Sample ◽

Pulsed Electric Field ◽

Yeast Cells ◽

Iron Ions ◽

Metal Ion Binding ◽

Yeast Saccharomyces Cerevisiae

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.

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Effects of Pulsed Electric Field-Assisted Osmotic Dehydration and Edible Coating on the Recovery of Anthocyanins from In Vitro Digested Berries

Foods ◽

10.3390/foods8100505 ◽

2019 ◽

Vol 8 (10) ◽

pp. 505 ◽

Cited By ~ 2

Author(s):

Gabriel Oliveira ◽

Urszula Tylewicz ◽

Marco Dalla Rosa ◽

Thomas Andlid ◽

Marie Alminger

Keyword(s):

Gastrointestinal Tract ◽

Electric Field ◽

Osmotic Dehydration ◽

Pulsed Electric Field ◽

Edible Coating ◽

The Stability ◽

Berry Fruits ◽

Shelf Stable ◽

The Impact

Berry fruits, such as strawberries and blueberries, are rich sources of anthocyanins. Several studies have been made on the impact of non-thermal treatments on safety, shelf-life and nutritional characteristics of such products, but the effects of these processes on anthocyanin stability during digestion in the gastrointestinal tract are still not completely clear. The aim of this study was to assess the recovery of anthocyanins after simulated gastrointestinal digestion of (1) strawberry samples, pre-treated with pulsed electric field (PEF) at 100 or 200 V·cm−1, prior to osmotic dehydration (OD), and (2) blueberry samples coated with chitosan and procyanidin. After digestion, a significantly higher content of cyanidin-3-O-glucoside and malvidin-3-O-glucoside was quantified by LC-MS/MS in processed strawberry and blueberry samples, compared with the controls. The highest recovery of cyanidin-3-O-glucoside was detected in digested strawberry samples osmotically dehydrated with trehalose. The recovery of malvidin-3-O-glucoside was highest in digested blueberries coated with chitosan and stored for 14 days, compared with untreated samples or samples coated with chitosan and procyanidin. Our study shows the potential of mild PEF treatments combined with OD, or the use of edible coating, to obtain shelf-stable products without substantially affecting the composition or the stability of anthocyanins during digestion in the upper gastrointestinal tract.

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