Ever noticed the word ‘High Pressure Processing’ on the packaging of the juices you drink and processed food you consume. If not, then this post for you explaining all about the term ‘High Pressure Processing’.
What Is High Pressure Processing?
Consumers have a growing preference for convenient, fresh, healthy processed food products with natural flavor and taste.High pressure processing is a promising “non-thermal” technique for food preservation that efficiently inactivates the vegetative microorganisms. This process is carried out at an intense pressure range of 100-1000 MPa, with or without the application of heat.
Principle of High Pressure Processing Technology
High pressure technology acts instantaneously and uniformly throughout a mass of food. It does not depend on size, shape and food composition (i.e. it is ‘isostatic’). The high pressure causes destruction of micro-organisms. In general, bacteria in the log phase of growth are more sensitive to high pressure than cells in the stationary, dormant or death phases. Moderately high pressures (300–600 MPa) kills or inactivates the vegetative microbial cells. A pressure of 350 MPa applied for 30 min or 400 MPa applied for 5 min will cause a ten-fold reduction in vegetative cells of bacteria, yeasts or moulds.
High pressure collapses the intracellular vacuoles damaging cell walls and cytoplasmic membrane. High pressures only affect non-covalent chemical bonds (i.e. ionic, hydrogen and hydrophobic bonds), leaving covalent bonds intact. This permits destruction of microbial activity without significantly affecting food molecules that contribute to the texture or flavour of the food. Additionally, the process does not require the use of chemical preservatives to achieve an adequate shelf life of processed products. The uniform application of high pressure to all parts of a food, irrespective of its size or shape is a significant advantage over other methods of processing.
Applications of High Pressure Technology
- Fruits And Vegetables : HPP is the ideal alternative to heat processing for fruit & vegetable products. The main advantage is achieving a significant shelf life extension while keeping fresh and home-made taste. Products maintain higher sensorial, functional and nutritional values while improving food safety. HPP produces high value added products: premium, exportation, RTE, natural and/or organic. Wet salads, purees, coulis, sauces, smoothies, chunks, slices, ready-to-eat products etc. are some examples of products processed by HPP.
- Meat & Fish Industry: Meat products have been the main drive of HPP technology in the last years.Sliced ham, turkey or chicken cuts, ready-to-eat products, whole pieces of cured ham, Oysters, clams, mussels, lobsters, crabs, shrimp, cod, hake, RTE seafood meals, are the products processed with HPP.
- Food Packaging: The type of food packaging used also plays an important role in HPT. Several different types of packaging used, like plastic stomacher bags, sterile tubes, polyester tubes and various other flexible pouch systems. The physical and mechanical properties of the material greatly influences the effectiveness of HPT on the food material.
- Dairy Technology: HPP induces changes in the functional properties of whey protein as well as in other milk components and native constituents. The high pressure slightly improved the microbiological quality of milk without modifying lacto peroxidase activity. HPT can improve the coagulation properties of milk and can increase moisture retention of fresh cheese.
Advantages of High Pressure Processing Technology
- High Pressure Technology is suitable for products with high water content.
- Helpful in processing raw product without significantly altering their flavor, texture or appearance.
- HPT develops product packaging to withstand a change in volume up to 15 % followed by a return to its original shape without losing seal integrity or barrier properties.
- HPT is equally effective on molds, bacteria and viruses.
- Combination high-pressure processing and heat (pressure-assisted thermal sterilization) provides benefits producing shelf-stable foods by inactivating spores.
Limitations of High Pressure Processing Technology
- Capital cost for a commercial scale HPT plant is high.
- Machinery required is complex as well as requires extremely high precision in its construction, use and maintenance.
- HPT unit immediately becomes rate limiting steps in most processing operation.
High pressure technology proposes a great potential to develop new “minimally” treated foods with high nutritional and sensory quality, novel texture and with an increased shelf-life. The novelty of HPP technology and high equipment costs are barriers to its commercialization but increased consumer’s demand for fresher-tasting foods containing fewer preservatives drives an increase in this segment. HPP can preserve food products without heat treatment or chemical preservatives, and its ability to ensure safety and significantly extended refrigerated shelf life has opened new market opportunities particularly in the area of “natural” preservative free food products. As a result it is nowadays accepted in the market.
Here is a visual depiction of the process of High Pressure Processing. See the video below,