PEF Treatment of Beverages

Product Examples: This includes smoothies, smoothie purees, fruit juices, vegetable juices, and other types of beverages.

Objective of PEF Treatment: The primary goals are microbial inactivation, cell disintegration, enhancement of extraction and refining efficiency, and prolonging shelf life.

Shelf Life

PEF treatment permeabilizes the cell membranes of microorganisms, enabling a targeted increase in shelf life while retaining the product’s quality and freshness. For juice preservation, a field strength of 10-20 kV/cm and energy delivery of 50-120 kJ/kg are appropriate. The shelf life of cold-pasteurized drinks is comparable to that of thermally pasteurized foods. However, a challenge is that enzymes are not fully inactivated after PEF treatment. Sterilization combining heat and PEF treatment is possible, but challenges include the effects on enzymes, spores, and aseptic filling. (Also see: Enzymes)

Low Acid Products

For low acid products like banana and kiwi puree, sterilization using combined heat and PEF treatment is effective in avoiding color changes and inactivating spores and enzymes. For instance, standard thermal treatment of these purees at 130-135°C (266-275°F) results in color changes to pink for banana and brown for kiwi at 90-95°C (194-203°F). Product and process improvements can be achieved by using lower temperatures followed by PEF treatment in less than a second.

Fruit Extraction Enhancement

This application is used for fruit extraction to obtain purees from fruits like mango, apricot, peach, and apple. (See: Solids/Fruit Products section).

Benefits of PEF

  • Longer shelf life without the drawbacks of thermal pasteurization.
  • Retention of vitamins, minerals, pigments, and flavors.
  • Healthier, fresher, and more appetizing pasteurized beverages.
  • Minimal effect on proteins.
  • A continuous and fast technique.
  • Higher pressing yields for juice production.
  • Increased extraction and refining yields.
  • Enhanced process efficiency due to significant reductions in energy, labor, and running costs.
  • Extended shelf life allows for greater flexibility in production planning.
  • Small equipment footprint and quick process start-up.
  • Low energy requirements.

Limitations

For microbial inactivation in liquids, PEF is applicable to pumpable products with a particle diameter of less than 20 mm. For cell disintegration purposes (tissue softening) to enhance extraction and refining efficiency, 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 l/h (1320 US gal./h) for microbial inactivation and up to 50,000 kg/h (110,000 lb/h) 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 Dollarcent per lb for cell disintegration of plant cells and 4.92 US Dollarcent per gallon for microbial inactivation of liquids.

PEF + Beverages?