9. Read and translate text c: "Freeze – dried foods"

dehydration Dehydration, as used here, means to take water out.

rehydration Rehydration, as used here, means putting water back.

vacuum A space from which air or other gases has been almost completely removed. The vacuum chamber mentioned in this passage has air pumped out of it until the pressure of the air within is well below the normal pressure of the air in the atmosphere.

porous Something that is porous is full of tiny holes through which liquid, light, or air may pass.

If "the way to a man's heart is through his stomach", the way to the moon is through freeze – dried foods. Because of weightlessness in space, astronauts can only eat food that is packaged in plastic containers so that it can be sucked out through a straw. These foods are prepared in the same way as freeze – dried coffee.

Freeze – dehydration, or freeze – drying, is a process in which moisture is removed from a quick – frozen food. The food does not change very much in shape, color, or taste. Later, the food can be rehydrated quickly by adding water to it. This rehydrated food tastes much like the fresh product.

To make it easier to dehydrate foods, they are sliced, diced, granulated, powdered, or liquefied. After the food has cooked it is quick- frozen. The frozen food is then placed on drying trays that are put in a special vacuum chamber or oven. The pressure in the chamber is then reduced.

Heat is applied gradually through heating plates or coils, raising the temperature of the trays to 200 – 300° F. Temperatures are then slowly reduced so that the temperature of the dried product does not exceed

140°F. Under these conditions the ice crystals in the frozen product change directly from a solid to a gas. The vapor, or gas, is taken out of the vacuum chamber through a tube.

The freeze – dried food has a porous texture and is very lightweight. It has only 2 or 3 percent of its original water content. In practically all cases, only water is removed by the freeze – drying process. The important oils and flavors remain.

1. The title that best describes the main idea of this passage is:

1. Food for Astronauts

2. From a Soil to a Gas

3. Vacuum Chambers

2. The fact that the important oils and flavors remain after freeze- drying is evidence that

1. freeze – drying improves the taste of food.

2. freeze – drying doesn't change the taste of the food.

3. freeze – drying can produce new foods.

4. freeze – drying changes the water in the food into oil.

3. The freeze – dried food would not be as lightweight if

1. it had much more than 2 or 3 percent of its original water content.

2. the oils and flavors were removed.

3. the gas was not withdrawn from the vacuum chamber through a tube.

4. the food was not cooked first.

4. The process of freeze – dehydration does all of the following except

1. change the oil content of food

2. freeze food

3. remove most of the liquid from food.

4. change the weight of food.

5. What does "reduced" mean in this passage?

1. reversed

2. lessened

3. strengthened

4. increased