PEF for Vegetable Products

Product Examples: Vegetable puree, pre-cut vegetables, roots, dried sweet peppers, peeled tomatoes, vegetable juices, and smoothies.

Aim of PEF Treatment: Cell disintegration, stress induction, improved peeling and extraction efficiency, drying enhancement, microbial inactivation, prolonged shelf life.

Tomato Peeling and Extraction

Pulsed electric field treatment at ambient temperature softens tomatoes, enhancing peeling efficiency. This method can replace the standard thermal treatment required before peeling potatoes. PEF treatment is more energy-efficient than heat treatment, reducing energy costs. It is also effective for lycopene extraction from tomatoes, a carotenoid pigment responsible for their red color, increasing the extraction yield.

Structure Modification

Targeted structural modification with PEF allows for the processing of tough and inconsistent produce like sweet potatoes, turnips, and beetroot.

Drying Enhancement

PEF treatment softens vegetable tissue before drying, improving water mass transport. This technique is beneficial in the production of dried sweet peppers. The field strength for this treatment ranges from 1.0 to 3.0 kV/cm, with energy delivery between 5 to 10 kJ/kg.

Broccoli & Stress Response

PEF can induce the formation of secondary metabolites in broccoli. In this case, the field strength is relatively low, between 0.1 and 0.5 kV/cm, with energy delivery from 0.1 to 1.0 kJ/kg.

Vegetable juices

PEF treatment effectively inactivates microbes in vegetable juices while retaining product quality and freshness.

Benefits of PEF

  • Nutritional enrichment with secondary metabolites due to stress induction in plant cells.
  • Targeted and controlled modification of vegetable tissue.
  • Enhanced handling due to tissue softening.
  • Improved peeling and cutting.
  • Increased process capacity.
  • For vegetable juice production, PEF results in greater extraction and refining yields, longer shelf life, and higher process efficiency with significant reductions in energy, labor, and running costs.
  • Retention of vitamins, minerals, pigments, antioxidants, flavors, and colors, producing a healthier, fresher, and more appetizing final product.
  • Minimal impact on proteins.
  • Extended shelf life enhances flexibility in production planning.
  • Continuous process and rapid technique.
  • Compact equipment footprint and quick process startup.
  • Low energy requirements.

More Information

Limitations

PEF is suitable for preserving liquids (microbial inactivation) in pumpable products with a particle diameter of less than 20 mm. For cell disintegration purposes (tissue softening) to enhance extraction, peeling, cutting, and drying, there are no size limitations for the raw products.

Equipment

Pulsemaster has developed industrial-scale equipment, named Conditioner, with treatment capacities up to 5,000 liters per hour (1320 US gallons per hour) for microbial inactivation and up to 50,000 kilograms per hour (110,000 pounds per hour) for cell disintegration.

Costs

On a commercial scale, total costs are expected to be around 1 Euro/ton (0.1 Eurocent per liter or kg) for the treatment of plant cells and 10 Euro/ton (1 Eurocent per liter or kg) for microbial inactivation. In US dollars, this equates to approximately 0.056 US cents per pound for cell disintegration of plant cells and 4.92 US cents per gallon for microbial inactivation of liquids.

PEF + Vegetable Products?