Write answers the following questions.
(a) Name the constituents of food and give five examples of each.
(b) Name some fibrous foods.
(c) Why it is necessary to preserve foodstuffs?
(d) What are the various methods of preserving food?
(e) What is meant by pasteurisation?
(f) Give the names of chemical preservatives.
(a) The constituents of food are as follows:
Carbohydrates - chapatis, rice, potato, corn, maize, papaya
Proteins - egg, meat, gram, peas, soybeans, beans, fish
Fats - butter, ghee, meat, fish, eggs
Roughage - pulses, fruits and vegetables
Vitamins −
Vitamin A is present in egg, butter, ghee, milk, carrots, tomatoes, papaya, mango, guava and leafy vegetables
Vitamin B-complex is present in animal liver, wheat and rice
Vitamin C is present in tomatoes, orange, guava, lemon and amla
Vitamin D is present in milk, butter, liver, eggs and fish
Vitamin K is present in cabbage, tomato, spinach and soybean
(b) Some fibrous food - pulses, beans, cucumber, banana, grapes and carrots.
(c) Preservation of foodstuffs is important as it helps in maintaining the nutritional quality and flavour of the food product for a longer duration. It also prevents the spoiling of foodstuffs.
(d) The various methods of preserving food are:
Dry storage - Food items such as pulses are stored in dry airtight container whereas grains are kept in a dry place to prevent spoilage from worms and insects.
Storage using low temperatures - In order to prevent the growth of microbes on food, it should be preserved at low temperature. Low temperature does not allow microbes to grow. For example, refrigerators.
Storage using high temperatures - Boiling kills the germs present inside it and prevents the spoilage of food.
Use of preservatives - Food items such as vegetables can be pickled in vinegar and also by using salt and oil. Fruits can be converted into jams and jellies or can be stored in sugar syrup.
(e) Pasteurisation is a method in which a liquid is first heated to a specific temperature for a particular time period followed by immediate cooling. This results in the inactivation of the microorganisms causing spoilage.
(f) Examples of some chemical preservatives:
Sodium metabisulphate, citric acid, boric acid, acetic acid/vinegar