How can PEF technology be implemented in juice production?

PEF, or Pulsed Electric Field, is a technology and a non-thermal pasteurization method. It involves applying short, high-voltage pulses to a liquid food product, such as juice, to kill or inactivate microorganisms present in the juice. In this post we cover how PEF can be implemented in the juice production process and what impact to expect.

The PEF process works by subjecting the juice to an electric field for a very short duration. The electric field disrupts the cell membranes of microorganisms, such as bacteria, yeasts, and molds, effectively killing them or rendering them inactive. This helps to extend the shelf life of the juice and reduce the risk of spoilage.

Compared to traditional pasteurization methods such as heat treatment, PEF offers several advantages. It is a non-thermal process, which means it can preserve the sensory and nutritional qualities of the juice better. PEF treatment does not significantly affect the taste, color, and vitamin content of the juice, as it operates at lower temperatures.

 

Additionally, PEF treatment can be performed quickly, allowing for high-throughput processing. It also has the potential to reduce the need for chemical preservatives in juice, as it provides microbial inactivation without the use of additives. 

Also, during juice extraction or production, PEF can be applied on disintegrated fruit or vegetables wherein the cell membranes in the pulp matrices are ‘opened up’ leading to enhanced juice extraction as well as increased release of vital nutrients often locked up in cellular organelles. PEF therefore leads to enhanced juice yield, and quality thereby enhancing productivity and creating less waste. In a nutshell, PEF can be considered as a technology of choice especially considering its low carbon footprint and hence overall sustainable processing.

 

An example of this is the results achieved with OptiCepts PEF technology in passion fruit juice and in the extraction of juice from pineapple stems to extract Bromelain.

Short high voltage "hits" the cells as the pass through the treatment chamber.
PEF technology for juice production in production line
Depending on what effect you wish to achieve the applications are installed in different places in the production line. They can also be combined.

Quality vs. Quantity - the juice industries challenges

The highly competitive juice market with many established brands and new entrants vying for market share is in constant need of developing new and better products. Consequently, technology like CEPT® based on pulsed electric field, is a way of not only improving the end product but also increasing production efficiency.

 

Equally important is consumer preferences. Consumers are increasingly concerned about health and wellness and are seeking out products that are natural, organic, and free from artificial ingredients.

 

In effect, the PEF processing technology with minimal heat impact that boosts the cellular release of minerals, vitamins, color compounds, and other micronutrients enhances quality substantially, is an attractive solution.

High-quality cold-pressed juices are often expensive to produce, but with an in-line application based on PEF, it is possible to produce high-quality juices at a lower cost.

What types of juice are suitable for PEF treatment?

The suitability of a juice for PEF (Pulsed Electric Field) treatment depends on several factors, including its physical and chemical characteristics. Here are some key considerations to determine if a juice is suitable for PEF treatment:

  • 1. Conductivity: PEF treatment relies on the conductivity of the liquid to facilitate the transmission of electric pulses. Juices with higher electrical conductivity are generally more suitable for PEF treatment. For example, fruit juices with a higher sugar content tend to have higher conductivity, making them good candidates for PEF.

 

  • 2. Viscosity: The viscosity of the juice affects the ability of electric pulses to penetrate and uniformly distribute throughout the liquid. Lower viscosity juices are typically more amenable to PEF treatment since the pulses can propagate more easily. If the viscosity of a juice is too high, adjustments may be required, such as dilution or the addition of suitable ingredients to optimize PEF effectiveness.
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  • 3. Particle Size: PEF treatment is typically more effective in juices with smaller particles or homogenized juices. Larger particles, such as pulp or pieces of fruit, may impede the transmission of electric pulses and reduce the efficiency of microbial inactivation.

 

  • 4. pH Level: The pH of the juice can influence the effectiveness of the PEF treatment. Some microorganisms are more sensitive to PEF at specific pH ranges. Acidic juices, such as citrus juices, tend to have lower microbial proliferation, making them favorable candidates for PEF treatment.

 

  • 5. Desired Shelf Life: PEF treatment can extend the shelf life of juice by inactivating microorganisms. If a juice has a shorter initial shelf life or higher microbial load, PEF treatment may be particularly beneficial.

 

It’s important to note that while these factors generally contribute to the suitability of a juice for PEF treatment, the specific parameters and requirements may vary based on the equipment used, target microorganisms, desired shelf life, and other factors.

Conducting lab-scale trials or consulting with PEF equipment manufacturers or experts can help determine the feasibility and optimization of PEF treatment for a specific juice product.

 

Contact OptiCept for further information

Pulsed Electric Field - Effects on various types of juices

PEF has the potential to be a valuable technology in the juice industry, offering a non-thermal method of microbial inactivation while preserving the quality of the juice. Furthermore, increasing efficiency by increasing extraction volumes impacts both sustainability and margins.

 

In general, PEF positively affects both yield and quality, but the impact varies depending on what type of commodity is processed. Let’s have a close look at its effects on some of the most popular juices.

Apple juice

Apple juice is a widely consumed juice variety. Apple juice is primarily composed of carbohydrates, mainly in the form of natural sugars, such as fructose, glucose, and sucrose. These sugars provide energy. It also contains Vitamin C, Potassium, Antioxidants, Dietary Fibers, Polyphenols, and other healthy micronutrients.

 

Depending on processing methods its content may vary in its volumes.

With PEF technology applied to apple juice, it is possible to retain these nutrients while at the same time increasing yield.

Pineapple juice

Pineapple juice is enjoyed in many tropical regions and is appreciated for its tropical flavor and natural sweetness.

 

Pineapple juice is a rich source of vitamin C (ascorbic acid) as well as bromelain, an enzyme with potential health benefits. Bromelain is known for its anti-inflammatory properties and its ability to aid in digestion.

 

PEF technology has shown a great impact on pineapple juice. OptiCept has started a pilot project with Dole to learn more about the patented PEF treatment CEPT on their pineapple products.

This far, OptiCepts PEF system has had a significant impact in increasing extraction yield, furthermore showing interesting results when applying a combination of PEF and VI to make pineapple slices and chunks softer and juicier.

Cranberry juice

Cranberry juice has gained popularity for its perceived health benefits. Besides being rich in Vitamin C and E, Cranberry juice, particularly when made from whole cranberries, contains dietary fiber. Fiber supports digestive health and helps maintain regular bowel movements.

 

Cranberries are rich in antioxidants, particularly proanthocyanidins. These compounds may have various health benefits, including potential anti-inflammatory and urinary tract health-supporting properties.

 

Cranberry juice also contains manganese, an essential mineral involved in bone health, metabolism, and antioxidant defense.

 

OptiCept has conducted experimental studies on Cranberries with PEF technology.  The results show:

 

  • 3.6% to 9.5% increase in juice extracted
  • 1.8% to 5.7% reduction in the moisture content of the pomace
  • and up to 25% reduction in the drying time compared to control samples

 

Read more here: ->

Pomegranate juice

Pomegranate contains huge amounts of antioxidants. In fact, pomegranate contains more antioxidants than most other fruits and vegetables.

 

Applying Pulsed Electric Field treatment on pomegranate has shown great benefits.

 

  • Enhanced total polyphenols by over 40%.
  • Enhanced dissolved sugars (Brix) by over 35 %
  • Increased release of intracellular content or ions. Hence increased conductivity by over 11 %
  • Advanced ‘redness’ or anthocyanins

 

Read more about this here ->

Pulsed Electric Field on other types of juices

As mentioned above, several factors determine if PEF is an alternative in juice production. 

 

OptiCept has conducted several tests on a wide range of commodities, besides the ones mentioned above – beetroot juice, Blood orange juice, passion fruit juice, carrot juice, and even cold brewed green tea have shown great response. Recently, impressive results were shown for the extraction of juice from pineapple stems. Lab results show up to 40% increased yield from the stem to extract Bromelain.

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