Tuesday, November 9, 2010


Today's Today Tonight is talking about Fresh juice fresher which pointed out that most fresh juice in our supermarkets is not as fresh as we think - they are pasteurised with heat and stored for up to twelve months.

The show interviewed Damian Crock, a Chairman of the company Preshafruit, who claims their juice is as fresh as the day the fruit was picked. He said that they developed a technique "cold pasteurisation" which put product into a high pressure vessel and pressurised for a short period of time to kill bugs inside the juice.

I think his technique is a modified pascalization. I agree that it is better than heat treated 12-month old aseptic juice.

Pascalization, or high pressure processing (HPP), is a method of preserving and sterilizing food, in which a product is processed under very high pressure, leading to the inactivation of certain microorganisms and enzymes in the food. The technique was named after Blaise Pascal, a French scientist of the 17th century whose work included detailing the effects of pressure on fluids. During pascalization, more than 50,000 pounds per square inch (340,000,000 Pa) may be applied for around fifteen minutes, leading to the inactivation of yeast, mold, and bacteria.

In pascalization, food products are sealed and placed into a steel compartment containing a liquid, often water, and pumps are used to create pressure. The pumps may apply pressure constantly or intermittently. The application of high hydrostatic pressures (HHP) on a food product will kill many microorganisms, but the spores of some bacteria may need to be separately treated with acid to prevent their reproduction. Pascalization works especially well on acidic foods, such as yogurts and fruits, because pressure-tolerant spores are not able to live in environments with low pH levels. The treatment works equally well for both solid and liquid products.

Pascal is a pressure unit. 1 pascal (Pa) = 1 N/(m^2) = 1 kg/(m·s^2.)

No comments: