The various methods of preserving food
Different methods are employed to preserve food. Many the food items available in the cities of today are frozen. And freezing is preserving. By freezing meat and fish, these items are transported from where they are available to places where they are in demand. Refrigeration is of recent vintage anti in ancient times, salting, burying in ice and snow and drying were ways of preserving food. Vegetables and fruits are pickled for preservation. Salted fish is preserved Fish. Canning is one of the commonest ways of preserving food. Fruits and vegetables are canned and canning makes horticulture economical. It is Pasteur’s discovery of the microbe that revolutionised the canning industry. The canning industry is so well developed today that fruit and vegetables and other food items produced in a particular country in a particular season are available in other parts of the world at all times.
From time immemorial, preservation of food has been practised in one form or another. Scientific methods of preserving food were developed more than a century ago and the food preserving industry gathered momentum after the outbreak of the First World War. The wide assortment of preserved food items and their easy portability have created a fast increasing demand for such food. Preserved food is available all the year round and the different methods of preserving food assure a stable market to farmers and horticulturists.
In olden days salt was used for preserving food. The salted fish that is available in shops is an item of preserved food. When food items such as meat and fish are plentiful, in areas of the world where the refrigerator is not available, these are preserved by adding salt to them and drying. Salt inhibits fermentation. Vegetables are also preserved by pickling or dry salting. Then there is brining. Soaking of vegetables in a salt solution of pre-determined concentration for a certain length of time is called brining. This treatment is given only to vegetables like cucumbers which do not contain sufficient juice to form brine with dry salt. Properly brined vegetables will keep in vinegar for a long time. In recent years, new methods of sterilisation such as the use of electric current, ultra-violet rays and oligodynamic properties of silver have been used.
Food canning, one method of preserving food, was developed towar end of the eighteenth century. Nicholas Appert, a Paris confectioner and 2*® invented the process of preserving food in glass containers, and this marked ^ beginning of the canning industry, which today employs highly sophist*,cat ° techniques. When in the 1860s Louis Pasteur proved that micro-organisms the cause of food spoilage and pasteurization (destroying micro-organisms by heat treatment, thereby prolonging the normal keeping quality of food) began, food came to be canned on a large scale. The American Civil War, and in 1914 the First World War, gave a great impetus to the canning industry which witnessed unprecedented developments in both technique and scope. Tin and glass containers are generally used for food canning. Plywood containers are also used for preserving dairy products and a variety of other products, like lemon, cheese, minced meat, confectionery, etc. One principle involved in canning food is ‘processing’. It consists basically in the application of heat in varying degrees to the food in closed containers fora sufficiently long time to sterilize the contents before they are hermetically sealed. Fruits are candied to be preserved. This is done by impregnating fruit with cane sugar or glucose. When the candied fruit has a thin, transparent coating of sugar, it is called glaceed (or glazed) fruit. Crystallized fruit is candied fruit and it is coated with crystals of sugar.
We are familiar with preserved milk which takes three main forms: the evaporated milk, the dehydrated milk and the condensed milk. Preserved milk can be stored fora long time and transported to distant places. The evaporated milk has about one half of its water removed. Its food value is about the same as that of the pasteurized milk. The condensed milk depends on the sugar in it for preservation. In dehydrated milk, water is removed. This powdered milk is changed into liquid milk by adding water. Preserving food by drying is perhaps the oldest of the known methods. Food thus preserved in concentrated form is becoming popular owing to its low cost and convenient and easy transportability. Sun-drying of food is extensively practised in many tropical and sub-tropical countries where there is continuous sunshine during the drying season. The equipment used consists of drying trays and items like knives, lye-bath, etc. Fruits that are preserved by dehydration are apricots, bananas, dates, figs and grapes. There is mechanical dehydration, which requires a dehydrator that controls temperature humidity and air flow. Dehydration is the proper method of producing dried vegetables. Vegetables that are commonly preserved by this method are beans, cabbage, carrots, spinach, tomatoes and turnips.
Fruit juices, squashes and cordials are preserved. The large-scale cultivation of fruit and the dietetic value of fruit beverages make fruit juice canning necessary. Fruit juices that are extracted are immediately preserved to retain their natural taste and aroma. Some of the methods employed in preserving fruit extracts are pasteurization, addition of chemicals, addition of sugar, freezing and filtration. Fruit juices are also preserved by pressure, by gases and by electric current. The best way of preserving pure juices is by ‘freezing’. The juice is first de-aerated and is transferred into containers which are hermetically sealed and frozen. Fruit juice is also preserved by drying. It is done in the same way as milk drying. Hot air is passed through a chamber in which is sprayed fruit juice in the form of a very fine mist. By regulating the temperature, the fruit mist is dried and dry juice is collected. The powder is then packed in dry and closely stoppered containers. When dissolved, the powder makes a refreshing drink almost similar to the original juice. Carbonation is another method employed in preserving juices. The keeping quality of carbonated bottled fruit is enhanced by adding a certain quantity of benzoate.
The commonest method of preserving food'at home is by refrigeration. The refrigerator, which has considerably reduced the tedium of marketing, preserves food items such as meat, fish and vegetables for days. In olden days ice and snow were used to refrigerate things. It is the principle of evaporation that led to the creation of the modern refrigerator, which was invented by Carl Linde in 1877. We use the refrigerator to preserve not only raw food but also cooked food.
Boiling is another method of preserving food. Among food items that are preserved by boiling are jams and jellies. Jarp is prepared by boiling the fruit with or without water with a sufficient quantity of sugar. Jelly is prepared by boiling the fruit with or without water, straining, mixing the strained and clear extract with sugar and then boiling the mixture until it reaches a stage when it sets to a clear gel. In marmalade, slices of the fruit or the peel are suspended.
From time immemorial, preservation of food has been practised in one form or another. Scientific methods of preserving food were developed more than a century ago and the food preserving industry gathered momentum after the outbreak of the First World War. The wide assortment of preserved food items and their easy portability have created a fast increasing demand for such food. Preserved food is available all the year round and the different methods of preserving food assure a stable market to farmers and horticulturists.
In olden days salt was used for preserving food. The salted fish that is available in shops is an item of preserved food. When food items such as meat and fish are plentiful, in areas of the world where the refrigerator is not available, these are preserved by adding salt to them and drying. Salt inhibits fermentation. Vegetables are also preserved by pickling or dry salting. Then there is brining. Soaking of vegetables in a salt solution of pre-determined concentration for a certain length of time is called brining. This treatment is given only to vegetables like cucumbers which do not contain sufficient juice to form brine with dry salt. Properly brined vegetables will keep in vinegar for a long time. In recent years, new methods of sterilisation such as the use of electric current, ultra-violet rays and oligodynamic properties of silver have been used.
Food canning, one method of preserving food, was developed towar end of the eighteenth century. Nicholas Appert, a Paris confectioner and 2*® invented the process of preserving food in glass containers, and this marked ^ beginning of the canning industry, which today employs highly sophist*,cat ° techniques. When in the 1860s Louis Pasteur proved that micro-organisms the cause of food spoilage and pasteurization (destroying micro-organisms by heat treatment, thereby prolonging the normal keeping quality of food) began, food came to be canned on a large scale. The American Civil War, and in 1914 the First World War, gave a great impetus to the canning industry which witnessed unprecedented developments in both technique and scope. Tin and glass containers are generally used for food canning. Plywood containers are also used for preserving dairy products and a variety of other products, like lemon, cheese, minced meat, confectionery, etc. One principle involved in canning food is ‘processing’. It consists basically in the application of heat in varying degrees to the food in closed containers fora sufficiently long time to sterilize the contents before they are hermetically sealed. Fruits are candied to be preserved. This is done by impregnating fruit with cane sugar or glucose. When the candied fruit has a thin, transparent coating of sugar, it is called glaceed (or glazed) fruit. Crystallized fruit is candied fruit and it is coated with crystals of sugar.
We are familiar with preserved milk which takes three main forms: the evaporated milk, the dehydrated milk and the condensed milk. Preserved milk can be stored fora long time and transported to distant places. The evaporated milk has about one half of its water removed. Its food value is about the same as that of the pasteurized milk. The condensed milk depends on the sugar in it for preservation. In dehydrated milk, water is removed. This powdered milk is changed into liquid milk by adding water. Preserving food by drying is perhaps the oldest of the known methods. Food thus preserved in concentrated form is becoming popular owing to its low cost and convenient and easy transportability. Sun-drying of food is extensively practised in many tropical and sub-tropical countries where there is continuous sunshine during the drying season. The equipment used consists of drying trays and items like knives, lye-bath, etc. Fruits that are preserved by dehydration are apricots, bananas, dates, figs and grapes. There is mechanical dehydration, which requires a dehydrator that controls temperature humidity and air flow. Dehydration is the proper method of producing dried vegetables. Vegetables that are commonly preserved by this method are beans, cabbage, carrots, spinach, tomatoes and turnips.
Fruit juices, squashes and cordials are preserved. The large-scale cultivation of fruit and the dietetic value of fruit beverages make fruit juice canning necessary. Fruit juices that are extracted are immediately preserved to retain their natural taste and aroma. Some of the methods employed in preserving fruit extracts are pasteurization, addition of chemicals, addition of sugar, freezing and filtration. Fruit juices are also preserved by pressure, by gases and by electric current. The best way of preserving pure juices is by ‘freezing’. The juice is first de-aerated and is transferred into containers which are hermetically sealed and frozen. Fruit juice is also preserved by drying. It is done in the same way as milk drying. Hot air is passed through a chamber in which is sprayed fruit juice in the form of a very fine mist. By regulating the temperature, the fruit mist is dried and dry juice is collected. The powder is then packed in dry and closely stoppered containers. When dissolved, the powder makes a refreshing drink almost similar to the original juice. Carbonation is another method employed in preserving juices. The keeping quality of carbonated bottled fruit is enhanced by adding a certain quantity of benzoate.
The commonest method of preserving food'at home is by refrigeration. The refrigerator, which has considerably reduced the tedium of marketing, preserves food items such as meat, fish and vegetables for days. In olden days ice and snow were used to refrigerate things. It is the principle of evaporation that led to the creation of the modern refrigerator, which was invented by Carl Linde in 1877. We use the refrigerator to preserve not only raw food but also cooked food.
Boiling is another method of preserving food. Among food items that are preserved by boiling are jams and jellies. Jarp is prepared by boiling the fruit with or without water with a sufficient quantity of sugar. Jelly is prepared by boiling the fruit with or without water, straining, mixing the strained and clear extract with sugar and then boiling the mixture until it reaches a stage when it sets to a clear gel. In marmalade, slices of the fruit or the peel are suspended.
The various methods of preserving food
Reviewed by Jame Collins
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1:22 AM
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Reviewed by Jame Collins
on
1:22 AM
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