Preservation by Deep Freezing, Common Salt, Sugar

Question 1 Name food material which can be preserved by using sugar?

Question 2 Name food material which can be preserved by using common salt?

Question 3 Name food material which can be preserved by deep freezing?

Question 4 How do you preserve food by deep freezing?

Question 5 How do you preserve food by using common salt?

Question 6 How do you preserve food by using sugar?

• NCERT Solutions Class 8 Science

1)Preservation by Deep Freezing

Preservation of food by deep freezing means preservation of food by excessive cold. Deep freezing of food can be done by placing it in the freezer compartment of our refrigerator. When the food is kept in deep freezer then food gets frozen.

At the very low temperature in deep freezer, the growth of food-spoiled micro-organism is prevented completely. Due to this, the frozen food remains unspoiled and fresh for long periods.

Deep freezing method is used for the preservation of food like meat, fish, fruits and vegetables.

2)Preservation of Food by Common Salt

Common salt prevents the growth of food-spoiling micro-organism due to which it is used to preserve a number of food material. It is used to preserve meat and fish. They are covered with dry salt to prevent the growth of bacteria. Such meat and fish do not get spoiled easily.

It is used to preserve fruits such as raw mangoes, lemon, amla and tamarind. Common salt does not allow bacteria or fungus to grow on fruits and vegetable present in it.

3)Preservation of Food by Sugar

Sugar is used as a preservative in making jams and jellies from fruits. It reduces the moisture content from the fruits which inhibits the growth of micro-organism like bacteria which spoil the fruits.

The fruits which are preserved in the form of jams and jellies by using sugar as preservative are apple, mango, orange, strawberry, pineapple, guava etc.

Other Notes from Chapter 2 Micro Organisms Friend and Foe

• Micro-Organisms
• Groups of Micro Organism
• Where do Micro Organism Live
• Useful Micro organism
• Making of Curd and Bread
• Commercial Use of Micro organism
• Medicinal Use of Micro oragnaism
• Increasing Soil Fertility
• Cleaning the Environment
• Harmful Micro Organism
• Carriers of Disease causing micro organism
• Disease Causing Micro organisms in Animals
• Disease Causing Micro-Organism in Plants
• Food poisoning
• Preservation of Food
• Preservation by sun-drying, Heating, Cooling
• Preservation of food by mustard oil and Vinegar, Chemicals, Pasteurisation, Air-tight Packets
• Nitrogen Fixation
• Nitrogen Cycle