Тексты для чтения для студентов специальности 260302, 260504, 260401

Fats

Fats are oily substances that are a source of heat and energy. Animals and human beings take in sugars and starches and store the excess as fat. The ability to make fats from carbohydrates or similar materials is a characteristic of most living beings, including plants.

The fatty foods perform some very important functions in our lives; to do without them can be dangerous . Fats form a protective layer around the nerves to protect them from shocks.

Fats in the form of their derived components also play an important part in our brain and entire nervous system. So one may say that life without fat is impossible .

More than 60% of fats and oils in our diet occur in the food we eat. Milk, fish, dairy products, fruits, nuts and vegetables contain fat or oil.

Occurrence and formation of fats

There is only a physical distinction between a fat and oil. If liquid at ordinary temperature, the substance is called an oil. If solid, it is called a fat. Vegetable fats and oils predominantly occur in seeds and fruits but they also found in roots , stems and leaves of plants. In some seeds, for example, in some cereals , the fat almost exclusively occurs in the germ.

Fats are classified into three chemical groups based on the degree of saturation of their fatty acids.

Saturated fats are mainly derived from food of animal origin. They are normally solid at room temperature.

Monounsaturated fats (e.g. olive oil) are found mostly in plants and are generally liquid at room temperature.

Polyunsaturated fats are found mostly in plants such as sunflower, corn, soybean. Generally speaking monounsaturated fats are most healthful.

Carp

Cyprinus carpio

Length: 15-22 inches Weight: 1-7 pounds

Coloring: olive-green on back; yellowish belly

Common Names: German carp, European carp, mirror carp, leather carp

For centuries, Old World fish farmers have esteemed the carp as an eas­ily domesticated food fish, so immigrant farmers welcomed these familiar fish when they were first brought to North America in the late 1800-s.

But the carp soon left the farm for the continent's open lakes and streams. As a result, the carp harvest from the Great Lakes has grown stead­ily. They inhabit shallow, weedy shore­lines, particularly along the southeastern end of Lake Michigan and in lower Green Bay, where they are extremely abundant.

Many fishermen and duck hunters resent the carp. These large, omnivo­rous fish browse on submerged vegetation—uprooting plants on which ducks feed, muddying the waters and destroying vegetative foods and cover needed by other fish.

An increase in the commercial harvest of carp could help solve these problems, and food scientists have long been trying to develop better ways to process and market these fish. Its flesh is firm and palatable if it has been grown in clean water, and Lake Michigan carp in years past were harvested and sold commercially in a variety of forms. Unfortunately, many Great Lakes carp today – especially those southern Green Bay and its tributary Fox River – contain relatively high levels of contaminations and so cannot be marketed as a food fish.

Preservation of foods.

The spoiling of food is due to the action of certain microorganisms and ferments, which cause undesirable and sometimes harmful changes in foods. They change the appearance, flavor and odor and even the food value.

As the principle spoilage agents are normally present in food , to destroy them or to prevent their development becomes the chief problem of food preservation.

Methods commonly used include refrigeration , canning , freezing, drying , heating and common storage under suitable conditions.

Heating. Food is usually preserved through the application of high temperatures. A temperature considerably above that of the body may result in either a pasteurized or a sterilized product. Foods are commonly pasteurized by being held at a temperature from 60° to 66° for thirty to forty minutes, during which most of the organisms , although not all , are killed. This method is used for temporary preservation of milk and for preservation of fruit juices and other fruit products. Sterilization of a food involves heating for a longer time or at a higher temperature than is necessary for pasteurization .

Non-acid foods are heated longer than acid foods. Heating from thirty to sixty minutes at a temperature of 121° C is usually sufficient to destroy all bacteria.

Canning. This method is used if the effectiveness of pasteurization and sterilization of foods is to be extended significantly.

Before the discovery of canning it was impossible to keep perishable foods for longer time.

The first foods preserved by canning were sealed in glass, then tin containers were used. Today highly efficient machinery and improved containers make possible the production of immense quantities of canned foods for both home and commercial use.

Experiments have shown that often the canned food is superior in food value to the freshly cooked.

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Поташкина Ольга Ивановна

Новикова Эмма Борисовна

Английский язык

Рабочая программа, методические указания, контрольные задания и тексты для чтения для студентов заочной формы обучения 2 курса факультета Технологический Менеджмент специальностей: 260302 (2710), 260401 (2707), 260501 (2712), 260504 (2708).

Подписано к печати: 11.03.09

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