Food preservation

Food preservation (from the Latin conservare, " receive, preserve " ) is the process of treatment of foods so that they are more durable. Here, the destruction is to be stopped or slowed down, at the same time should nutritional value, taste, color and texture far as possible retained.

The decay, to prevent the preservation, usually occurs by microbial or makrobielle action. In the former case by means of microorganisms, in the latter case by bacteria, fungi, worms, insects and the like. Most common application is to obtain food in the stocks, in the household or in the kitchen, as well as preserving technique for collected food and similar natural history in museums and collections. The emergence of a food industry and the production of processed foods on a large scale was made possible by modern methods of preservation.

History

The preservation of food by salt ( salting ), smoke ( smoking ) or simple drying has long been known to mankind.

The beginning of modern heat preservation is usually associated with the work of two Frenchmen. With Denis Papin, who had already made ​​around 1700 experiments with the preservation of jellies and cooking meat in sealed with putty copper pots, and with Nicolas Appert, who presented in 1809 technically advanced methods of preservation. However, the theoretical solution was accompanied by many technical problems, especially when soldering the cans and the duration of the effect of heat on different foods that pasteurization was not invented until 1864.

First craft enterprises emerged in the German Confederation in the 1840s. No significant production volumes were only achieved in the 1860s. Pioneer region was Braunschweig, the preferred product the former luxury asparagus.

The transition to industrial forms occurred only in the 1870s. 1873, the autoclave was introduced in Germany, since 1889 also automatic machines can closure. However, the real breakthrough preserved food brought the department stores that offered canned since 1892 a mass audience.

Despite high growth rates, tinned food laws in Germany is not as strong as in the UK or the USA. One cause were relatively high prices that made the consumer in the Empire only for the middle and upper classes affordable. An even more important reason was that preserves were perceived as a health risk. ( Soldering was later replaced by crimping as a closure method) soldering the cans with lead | In the early days there was lead poisoning from soldering. Not only poisoning incidents, but especially the canning industry, which persisted wrongly on their expert knowledge and the supposed non-toxicity of many conservation techniques and means, led to a critical attitude. Parallel sat down in the households, the preservation of fruit, vegetables and meat by boiling increasingly.

A fundamental change occurred only since the late 1930s through the enforcement of cryopreservation. The freezing was supported under the Nazi Four Year Plan by the State with high resources, then sat down but only in the early 1960s, generally through.

Method

To prevent biological decomposition, there are five basic techniques that also occur in combination:

Combined procedures would be for example:

  • Refrigerator: Exclude pests, cools the food and light completion
  • Smoking, a combination of heating, drying and wrapping with preservative solutions
  • Jam boil: increase the sugar concentration and heating
  • Placing eggs in water glass: air seal and pH change ( alkaline)
  • Drying: lowering the water content and increase the sugar concentration

The change in protein-rich or carbohydrate-rich starting materials using microorganisms leads to new products, which generally have better durability than the original. But it is not only a preservative, but also a refinement (a " desired spoilage " ) - see also dairy products, fermentation and fermentation.

The occurring on almost all food reactions, especially enzymatic reactions are slowed by drying and cooling or deep-freezing, but can not be stopped by it. By heating only certain enzymes are destroyed, whereby the durability is extended; held certain enzymatic and chemical reactions, but on.

In the preservation of food or stimulants can be distinguished:

  • Fully preserved with a very long, at least a two-year shelf life,
  • Three quarters preserves which are stable up to 12 months ( at max. 20 ° C),
  • Semi-preserved ( Präserven ) that were made by chemical additives limited shelf life.

Trivia

In Stavanger ( Norway) there is a Hermetikkmuseet Norsk ( Canning Museum ).

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