In this article
The advantages of using PEF for extraction yield and processing time.
 3 min read

Pulsed electric field (PEF) treatment is a promising technology for fruit juice producers to complement conventional production methods. It can be implemented in existing processing lines as a pre-treatment, serving two goals: it enhances extraction yields and/or is a gentle preservation method, as an alternative to thermal pasteurisation, retaining nutrients and taste. PEF enables safer daily production and helps to reduce the energy costs for steam generation used in pasteurisation.

Extraction Yield

Various de-juicing systems were used to characterise the influence of PEF-treated fruit mashes on the extraction yield by pressing. On a pilot scale, a continuously working single-belt-press was used for apple juice pressing. Depending on the mash particle size, the yield increased between 3.8 - 6.6 % compared to the traditional process. PEF-treated strawberries pressed with a pneumatic filter press resulted an increase in extraction yield of almost 5%.

 

Preservation

PEF can be used also as a low temperature method for the reduction of bacteria and yeasts in fresh fruit juices, without affecting taste and nutrients. PEF was found to be beneficial for juices from apples, cherries and strawberries. Initial microbe concentrations were up to 10,000 per mL in freshly squeezed juices. Depending on the fruit, PEF reduced concentrations by up to 6 Log10 cycles (1,000,000 times smaller) without the need for a thermal pre-treatment. Freshly squeezed factory juices could be free from bacteria and yeasts, even at low energy use (60 kJ/kg).

Implementation

At the moment, PEF can be implemented in the production line in two places: after the crushing to facilitate juice extraction and after the pressing to preserve the juice. A different PEF chamber is needed for each application.

The incorporation of PEF into the juice process was also tested on an industrial scale. Regarding the yield improvement, a larger scale PEF system, developed by the FieldFOOD partner Energy Pulse Systems, reached a fruit capacity of up to 14 tons per hour. Regarding microbial reduction, a continuously operating PEF pilot plant was designed, assembled and equipped with a novel low-cost pulse modulator (PEF-MI, EPS). As intended, this new low cost generator allows for small producers to use this technology renting it at a running cost as low as  Euro 2c per litre.


About FieldFOOD

Within FieldFOOD project, PEF technology was tested and validated for five applications: olive oil, fruit juices, tomato peeling, cider and red wine. Benefits derived from the introduction of the PEF technology depended strongly on the specific application. Modular, portable, low cost PEF modulators developed during the project allow companies to evaluate this technology in the above-mentioned sectors or for new applications.

FieldFOOD focussed on practical challenges like the implementation of PEF in existing pilot and industrial processing lines, adjustment of pre-treatment and subsequent processing steps. Here, both research institutions and SME benefited from a close collaboration during the last months. For more information visit the FieldFOOD website or contact the project coordinator Javier Raso.

FieldFOOD an EU funded initiative

FieldFOOD stands for:  Innovative food processing technologies.

For whom: Food processors of plant-based food such as Wineries, Olive oil companies, Tomato products companies, Fruit juices companies and Cidery.

Objective: Provide innovative solutions to overcome existing bottlenecks that prevent the implementation of Pulsed Electric Fields (PEF) in the food industry.

Reason: Effects deriving from PEF processing are very attractive to the food industry in order to improve food quality and process efficiency, reduce energy inputs and enhance eco-friendly processes.

How: By conducting a systematic process analysis of the processing lines of the different companies for a successful integration of the PEF technology in order to replace or complement the existing processing and by designing modular portable low-cost pulse generators to be installed in the processing plant of the companies involved in the project.

Areas of interest: Food processing, Equipment manufacturing, Food safety, food quality, sustainability.

When: From April 2014 to April 2018. 

Funded by: European Commission (635632-FieldFOOD-H2020).


Want to get more information about this topic?
Get in touch
Contact person:
Matthias Schulz
Function:
Engineer Food Technology Research Assistant
Company:
Technische Universitaet Berlin
Country:
Germany


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