Canning of foods

Canning of foods used to lengthen retention period, which is of special importance for perishable products. For conservations of foodstuff use a variety of ways - physical, chemical and biological. Physical methods most widely conservation through low (cooling, freezing) and high (sterilization, pasteurization) temperature.
When cooling the product is stored at the temperature from 0 to +4 degrees. In such conditions the products reduces the activity of oxidation processes and stops the growth of pathogenic and saprophytic microorganisms. However, chilled products continue to change, so the shelf life of their limited to 10-20 days.
In cases when you need to store the product for a longer period, apply freezing. For this purpose use a temperature of the order of 20 degrees. Freezing almost does not change the original properties of the products and ensure their high quality.
Preserving of high temperatures is held by sterilization, pasteurization, drying.
When sterilization is the total destruction of all forms of bacteria. This is achieved by autoclaving at a temperature of 100-120 degrees and exposition 30 minutes Cans after sterilisation can be kept from 1 year to 1 to 5 years.
Pasteurization involves the destruction of vegetative forms of microorganisms. To do this more often applied temperature 63 deg for 30 min (long pasteurization).
In the short-term pasteurization is used relatively high temperature - 85-90°, but the exposure time is thus limited to 30 sec - 1 min Intermittent pasteurization use in the manufacture of fruit juices and milk in large enterprises, where it is necessary to ensure continuity of the process of pasteurization. After pasteurization the product is almost does not change its initial properties and preserve vitamins.
Drying - dehydration food in a stream of hot air or by direct contact with a heated surface. With humidity less than 15% stops multiplication of bacteria.
Drying - dehydration products drying in the sun. When drying vitamin C is destroyed completely, and carotene - partially.
Canning salt. When the content in preserving the environment 9-10% salt delayed the growth of bacteria due to dehydration. In addition, the salt reduces the amount of oxygen in the environment, preventing the development of aerobes. When the Ambassador of the vitamin is destroyed, and a part perehodim in brine.
Canning sugar. When the sugar content of 70% of the product is high osmotic pressure, which inhibits the growth of microorganisms. Canning sugar by simply mixing with sugar without heating retains its original properties (taste, aroma and vitamins.
Preserving the marinating. When marinating products with food acids (acetic, citric) shift reaction acidic side, which leads to the retardation of development of microflora. It is also promoted salt and spices. To preserve vegetables often used in pickling. When pickling under the influence of microflora present in vegetables, fruits (lactic microflora), is the conversion of sugar into lactic acid, which suppresses the growth and development of putrefactive bacteria. Salt added during pickling, also inhibits the growth of microorganisms.
Canning Smoking. When Smoking are three factors: dehydration, elevated concentrations of salt and antiseptic substances contained in the smoke. Smoking can be hot and cold. Cold Smoking is made at a temperature of 25-30 degrees and in a period of 3-7 days. After Smoking product has a specific taste and smell. Hot Smoking is carried out at a temperature of 120-140 degrees and in a few hours. This method can often fish. After hot smoked fish unstable during storage, so in the trading network of shelf life is limited to 72 hours at a temperature of no higher than 8 degrees.
Canning of ionizing radiation. Currently, in different countries of the developed method of preserving food by treating them with ionizing radiation of radioactive isotopes. This method is cheap, but when irradiated with high doses change organoleptic properties of the products: they have become extraneous tastes and smells. Food irradiation is almost not destroyed amino acids and vitamins.