From Top Wiki
Pascalisation (pascalization), also known as High Pressure Processing (HPP) or Ultra High Pressure Processing (UHP) is the name of a preservation technique for food products. English terminology is often used for high pressure techniques, of which HPP is the most common one. Other names used are Ultra High Pressure (UHP or UHD), High Isostatic Pressure (HIP) and High Hydrostatic Pressure (HHP). Characteristic for this preservation technique are the low temperature and extremely high pressure. The high pressure inactivates harmful pathogens and vegetative microorganisms that cause spoilage. Due to the lower temperature there is a better retention of the original nutritional value and natural sensory qualities of the food product.
A Pascalisation treatment takes place in a pressure vessel. The pre-packaged product is placed in a pressure fluid (usually water). The pressure is increased by pumping additional liquid into the pressure vessel until the desired pressure is reached (100-600 MPa). After a few minutes, the pressure is lowered, after which the batch treatment is finished. Because the pressure vessel is pressurized in isostatic manner, the whole product undergoes the same uniform treatment. A cold pasteurization can thus be carried out at room temperature.
High-pressure treatment is a relatively old technique: in 1899 Hite already described that milk could be pasteurized using high pressure. In the chemical industry the process is used for the production of polyethylene. For this purpose, pressure vessels of a few hundred liters are used, with a pressure range around 300-400 MPa. About twenty years ago high pressure was commercially introduced in Japan for food preservation. At present, the technique is used for a large range of products, such as orange juice, guacamole, ham, oysters, rice and fruit desserts. Geographically, it’s mostly used in Japan, the United States and Europe. See the following site for a list of commercially available products. There are approximately 220 production lines worldwide. Macromolecules may change in shape and properties under pressure. Processes that (partially) take place are protein denaturation, crystallization of fats and gelatinization of starch. High pressure has no influence on small molecules such as flavour compounds, fragrances and vitamins. However, because enzymes and micro-organisms will become inactivated under high pressure, a preserved product is created by the treatment, with a fresh(er) taste, aroma and colour versus a heat pasteurised equivalent. The main driving force for reactions under pressure is the volume of the reaction product. Proteins (including enzymes) tend to denature, while micro-organisms are inactivated due to both crystallization of cell membranes and (partial) denaturation of essential enzymes. Products can be packaged in a cup or bowl with top seal, in bottles, pouches, or pockets. Not all packaging types are suitable and often require pressure endurance validation before use.
Attainable Unique Selling Points for HPP products
- Combinations of liquid and solid ingredients, both cooked and raw
- Retention of raw/fresh flavour, colour and texture
- Retention of original nutritional value
- Shelf-life comparable to thermally pasteurised references
- Clean label options
Showcase applications for HPP added value in practise
- Cold raw vegetable soup (for example tomato Gazpacho-soup, cucumber Tzatziki-soup)
- Cooked sauces with crunchy raw vegetable pieces
- Farm fresh dairy (for example all-raw milk, whey protein, cheese)
- Fresh pesto, tapenade and dips (for example guacamole, salsa, hummus)
- Use of fresh herbs (i.e. basil, koriander, mint leaves) as product ingredient or topping (for example curry, cocktails)
- Raw cleansing drinks (for example aloë vera juice, green tea, vegetable juice)
- Ready to use fresh batter and dough (for example cookies, cakes, pizza, pie)
- Ready to eat meals with blended raw ingredients or separated raw components (for example pasta salad, potatoes with cream)
- Fresh raw fruit and vegetable purees or pastes
- Fresh PET-food
- Fresh meat, fish and seafood products
Requirements for HPP
- Processing packaging must be flexible and (often) HPP-proofed
- Product can be both solid and liquid
- Product may not contain enclosed gas (air bubbles collapse)
HPP generally results in inactivation of micro-organisms and enzymes, while leaving small molecules unaffected. Pascalisation is mainly used commercially for the pasteurization of food products. Typical treatment conditions vary between 300 and 600 MPa at room temperature, which inactivates vegetative bacteria and most of the enzymes, thereby extending the shelf-life with 4 - 8 weeks. The products can be treated in both large and small (consumer) packaging types.
On eliminating Salmonella and Campylobacter: The Dutch policital party "De Partij voor de Dieren" (Party for the Animals) asked the Dutch government on September 2009 whether this technique could provide a possible solution in the fight against food-borne illnesses by Salmonella and Campylobacter.
Below is a picture of an Avure 100L system (Sweden / USA), and a 3D rendered picture of a Chic Freshertec system (China).
Pros and cons
- Product quality is comparable with freshly-prepared products
- Treatment inside the product container ensures no recontamination
- Also suitable for “solid” products, such as meat and fish
- Throughput goes up to 3000 kg per hour
- High investment costs
- Incomplete inactivation of enzymes
- Only suitable for cold pasteurization (sterilization not yet commercially available)
- Tin or glass product container is not possible.
- Enclosed air is irreversably pressed out
Availability of equipment
Pascalisation systems are commercially available with a throughput of 500 to 3000 kg per hour. The following systems are suitable for the food industry:
- Avure: 100, 215 and 350 liters vessels; maximum pressure 600 MPa.
- NC Hyperbaric: horizontal drums from a volume of 55 liters, maximum pressure 600 MPa.
- Uhde: small high-pressure pumps and pressure systems
- Chic FresherTech: horizontal drums from 20L to 400L, maximum pressure 600 MPa
Manufacturers of laboratory equipment are: (1) Avure, (2) Resato International (3) Stansted (4) UHDE. In the Netherlands “TOP b.v.” and “FBR / WUR” have testing equipment available. In Germany “DIL”, and in Belgium “Flanders Food” also have equipment available for carrying out Pascalisation research. U.S. company “All Natural Freshness” supplies containers, transport carts, and other peripheral equipment for HPP.
Pascalisation costs about 10-15 cents per kg of product. It is also possible to use contractors as co-processors (cost 30-40 cents per kg product). The majority of this increased amount is due to incorporated depreciation of investment costs. At Avure a standard high-pressure unit costs approximately € 1 - 1.5 million. This excludes maintenance costs.
Below is a video of Avure explaining how product development takes place.
- TOP b.v. - Product development (food design/npd) and research surrounding pascalisation
- Pascal Processing b.v - Tolling and sales agent Avure
- All Natural Freshness (sales agent in Europe: Holland Innovations e.s.)
- Pascalisatie - vers onder druk (Voedingsindustrie, Maart 2012) (Dutch)
- "High-Pressure Processing Keeps Food Safe"
- "The Future is (almost) here"
- Pascalisation on Wikipedia (EN)
- Centre for Pascalisation