HIGH PRESSURE PROCESSING-A CLEAN TECHNOLOGY

Preservation of food is a vital necessity of mankind as such a course of action can ensure food security all the time. As most foods are seasonal in nature, excess production needs to saved away for future needs when production is not possible due to season and weather conditions. For the last 200 years man has been continuously striving to reduce food wastage through better technologies and the vast strides made by food technology have provided food industry with a wide range of choices vis-à-vis food preservation. One of the most elegant process evolved relatively in recent times makes use of the principle that when food is subjected to high hydrostatic pressure all living things in it are totally destroyed. Pressures as high as 50000 pounds per square inch can make inactive bacteria, molds and yeasts in less than 15 minutes. Many enzymes are also inactivated because of the susceptibility of protein to denaturation at the pressure employed. The 17th Century scientist Blaise Pascal who is the pioneer in high pressure processing (HPP)would not have imagined that the process named after him as "Pascalization" has such a high potential for saving foods from spoilage to day.

"High pressure in the food industry, as a new non-thermal method, is applied in many phases of food processing. This new non-thermal technology was developed in the 1990s. The main advantages of high-pressure processing are in the short time of processing which is between a few seconds and 30 minutes. Processing of solid or liquid food products with or without packaging happens in the temperature interval 5 – 90 °C, and pressures 50 – 1000 MPa. The driving pressure is distributed uniformly through the whole product independently 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 novel food technology. Combined with lower cost of treatment (but unfortunately higher initial cost of equipment) compared to traditional processing technologies, it is also 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 (sterilization, pasteurization). However, with the combination 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 microorganisms), freezing and defrosting of foodstuffs, production of fruit juices (pasteurization), processing of oysters, modification".

It was left to Japan to recognize the merits of HPP first and products like juices, jams and jellies became the first commercial products marketed by using this process. To day a wide range of foods like fish, meat, salad dressings, rice cakes, yogurts etc are shelf-stabilized using HPP. Only limitation for this process is that some enzymes are not inactivated leading to possible quality deterioration during extended storage. Similarly some spores are not affected, especially under low acidic environment, calling for combining HPP with other techniques for complete sterility. HPP works extremely well under acidic conditions where proteins get denatured, hydrogen bonds are fortified, non-covalent bonds are disrupted and nutrients are unaffected. High investment need for setting up the plant will naturally reflect on the cost of processing and products from HPP line are bound to be more expensive to the consumer. Probably fish and meat may remain the most suitable candidate for HPP technology because of their high value.

V.H.POTTY
http://vhpotty.blogspot.com/
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