New challenges for old problems

The harnessing of fire by our ancestors was one of the most important achievements in the development of humans. It made it possible to produce more digestible foods. Thus providing more nourishment and to improve brain development. It made it humans also more mobile because they could transport the fire with them. Heating of foods resulted in beneficial changes such as color, flavor or crust formation but also deterious effects occurred such as the formation of antinutritive substances and loss of heat sensitive nutrients.


About 200 years ago, the use of heat for food preservation led to the development of pasteurization (inactivation of unwanted microorganisms and enzymes) and sterilization (killing of resistant organisms such as bacterial spores). These technologies have been constantly improved and optimized. However, the negative effects of heat affecting food quality cannot be totally eliminated, because a given time/temperature regime is necessary to assure effective microbial inactivation to provide safe and non-perishable foods. Consequently alternatives to thermal process are constantly sought.


This article was prepared by Prof. Dietrich Knorr of the Department of Food Biotechnology and Food Process Engineering, Berlin Institute of Technology (TU Berlin), Berlin, Germany.

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