Tuesday, October 25, 2011: 02:55:36 PM

Food Processing Trend

High pressure food processing helps reduce germs, micro organisms

High Pressure Processing is being widely considered as the latest and safest technology in food processing

High Pressure Processing (HPP) is a widely known method of food processing where the food is treated at elevated pressure (upto 87,000 pounds per square inch or at approximately 6000 atmospheric pressure), with or without the application of heat in order to attain microbial inactivation or to alter the attributes of that particular food item to achieve customer-desired qualities. The pressure applied, helps to inactivate most vegetative bacteria, retain food quality, maintain natural freshness and extend microbiological shelf life.

 
High pressure processing causes minimal changes in the freshness of any food item by eliminating thermal degradation. HPP thus results in foods with fresher taste, better appearance, texture and nutrition. The technology is especially beneficial for heat sensitive products.
 
The ph and water activity of foods can also substantially affect the inactivation of micro-organism by high pressure processing.
 
Although the process, also known as pascalisation, was discovered way back in the year 1899, treating foods with high pressure is a relatively new method of preservation and one still under development.        

The process is named after Blaise Pascal, a 17th century French scientist who explained how contained fluids are affected by pressure.
 
Japan is considered to be the modern leader in this technology where the technique has been used since 1990 on some jams, juice and jellies.
 
Jams made by high pressure processing hold back the taste and colour of fresh fruit, unlike other conventional cooked jams. The process is also used in processing yoghurts, salad dressings and citrus juices.
         
What experts say
 
According to Dr VH Potty food technologist and chairman of Diversified Food Technologies (India), Mysore, India the basic advantage of HPP is its short time of processing, which is between a few seconds and 30 minutes. The operation of processing either solid or liquid food products with or without packaging happens within the temperature limit of 5 – 90°C, and pressures 50 – 1000 MPa. The driving pressure is distributed uniformly throughout the whole product independent of its quantity and shape. These processing characteristics combined with improved food microbiological safety, less energy expenditure, low concentration of waste products and longer shelf life make high-pressure processing a very promising food technology, adds Dr Potty.
 
Combined with this there is an added advantage of lower cost of treatment as compared to traditional processing technologies, which makes it economically profitable. The main purpose of such treated food products are in preservation of sensory, nutritive and textural properties. As the temperature increase is very low, there are no significant changes in sensory properties, in contrast to conventional thermal processing. However, with the addition of heating or cooling and high pressure, modification of existing and creation of new food products is possible. Today, high pressure is used for the treatment of meat products (inactivation of micro-organisms), freezing and defrosting of foodstuffs, production of fruit juices (pasteurisation), processing of oysters and modification.
 
Debojyoti Saha, a student of food technology, says, “The advantage of HPP is that it helps to deliver nutritious food items minus the micro-organisms which can often be harmful.”
 
However, the drawback of this method is that it is costly to implement. In recent years, food preservation strategies have been developed, which combine high pressure processing with the use of anti-microbial food additives.
 
Sambuddha Sengupta

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