1 The discovery of freezing has changed our eating habits more than any other related invention. Because many foods contain large amounts of water, they freeze solidly at or just below 32 degrees Fahrenheit. When we lower the temperature to well below the freezing point and prevent air from penetrating the food, we retard the natural process of decay that causes food to spoil. Freezing preserves the flavor and nutrients of food better than any other preservation method. When properly prepared and packed, foods and vegetables can be stored in the freezer for one year. 2 Most vegetables and some fruits need blanching before they are frozen, and to avoid this step would be an expensive mistake. The result would be a product largely devoid of vitamins and minerals. Proper blanching curtails the enzyme action, which vegetables require during their growth and ripening but which continues after maturation and will lead to decay unless it is almost entirely stopped by blanching. This process is done in two ways, either by plunging vegetables in a large amount of rapidly boiling water for a few minutes or by steaming them. For steam blanching, it is important that timing begin when the water at the bottom of the pot is boiling. Different vegetables require different blanching times, and specified times for each vegetable must be observed. Underblanching is like no blanching at all, and overblanching, while stopping the enzyme action, will produce soggy, discolored vegetables.
单选题
Why does the author mention 32 degrees Fahrenheit?
【正确答案】
B
【答案解析】The author's purpose is to identify the freezing point of water. Clues: Because many foods contain large amounts of water, they freeze solidly at or just below
单选题
Why does the author use the term expensive mistake in discussing blanching?
【正确答案】
B
【答案解析】The author's purpose is to warn that not blanching will harm the food's nutritional value. Clues: ...avoid this step...; The result would be a product largely devoid of vitamins and minerals.
单选题
What can be inferred about enzyme action in vegetables?
【正确答案】
A
【答案解析】You can infer that enzyme action in vegetables eventually causes vegetables to spoil. Clues: ...enzyme action, which vegetables require during their growth and ripening but which continues after maturation and will lead to decay
单选题
It can be inferred that underblanched vegetables would
【正确答案】
C
【答案解析】You can infer that underblanched vegetables would lack vitamins and minerals. Clues: ... to avoid this step would be an expensive mistake. The result would be a product largely devoid of vitamins and minerals; Underblanching is like no blanching at all....