Conserving Food Nutrients

21 Grade 7 Agriculture questions on Conserving Food Nutrients, with worked marking schemes. 21 questions are available on this topic in full.

1. Question 1

   1 mark

   Which of the following methods of food preparation conserves the greatest amount of vitamins in vegetables?

   A. Deep frying until brown

   B. Steaming for a short time

   C. Overcooking on high heat

   D. Boiling in plenty of water

   (1 mark)

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2. Question 2

   1 mark

   Which of the following is the best reason for cooking vegetables for a short time?

   A. To make them harder

   B. To retain heat-sensitive vitamins

   C. To increase water content

   D. To reduce their colour

   (1 mark)

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3. Question 3

   1 mark

   Salting and sun-drying of fish mainly help to conserve the fish by:

   A. Changing the fish into protein

   B. Preventing the growth of spoilage micro-organisms

   C. Increasing the fat content

   D. Adding vitamin C to the fish

   (1 mark)

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4. Question 4

   1 mark

   A Grade 7 learner is told to prepare vegetables in a way that keeps the most nutrients. Which of the following should the learner do?

   A. Cut the vegetables long before cooking and leave them in the sun

   B. Cook the vegetables for a short time using little water

   C. Peel off all the outer leaves and skins first

   D. Soak the chopped vegetables overnight before cooking

   (1 mark)

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5. Question 5

   1 mark

   Which food preservation method conserves nutrients by removing moisture so that micro-organisms cannot multiply?

   A. Chopping

   B. Adding water

   C. Drying

   D. Bruising

   (1 mark)

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6. Question 6

   5 marks

   A parent prepares sukuma wiki (kales) for the family but always boils the vegetables for a long time in plenty of water and then pours away the water. A Grade 7 learner who has studied nutrition suspects that nutrients are being lost in the way the vegetables are cooked.

   (a) State TWO mistakes the parent is making that lead to loss of nutrients from the vegetables. (2 marks)

   (b) Describe THREE correct practices the learner could advise the parent to use in order to conserve nutrients when cooking the vegetables. (3 marks)

   (5 marks)

   Marking scheme

   (a) Any TWO (1 mark each): boiling/cooking the vegetables for too long destroys heat-sensitive vitamins (e.g. vitamin C); using a lot of water and then throwing it away dissolves and washes out the water-soluble vitamins and minerals into the discarded water. (b) Any THREE (1 mark each): cook the vegetables for a short time / do not overcook them; use only a small amount of water; cover the cooking pot (cook in a closed pan); cut the vegetables into large pieces just before cooking to reduce surface area exposed; do not throw away the cooking water but use it in soup/stew; avoid adding bicarbonate of soda; wash the vegetables before cutting, not after.

7. Question 7

   1 mark

   Wanjiku boils her sukuma wiki in a large amount of water and pours the water down the drain before serving. Which nutrient is she most likely losing through this practice?

   A. Starch

   B. Fats

   C. Proteins

   D. Vitamin C

   (1 mark)

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8. Question 8

   1 mark

   A mother is preparing sukuma wiki (kale) for the family and wants to conserve as many vitamins as possible. Which method should she use during cooking?

   A. Boil the kale for a long time in plenty of water

   B. Cook briefly in a little water and avoid overcooking

   C. Soak the cut kale in water overnight before cooking

   D. Deep fry the kale until brown

   (1 mark)

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9. Question 9

   1 mark

   Which cooking practice is MOST likely to destroy nutrients in food?

   A. Reheating the same food several times

   B. Cooking with a tight-fitting lid

   C. Serving food immediately after cooking

   D. Steaming lightly

   (1 mark)

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10. Question 10

    1 mark

    A cook prepares sukuma wiki by chopping it into very small pieces, soaking it in water for a long time, then boiling it for thirty minutes and pouring away the water. Which mistake causes the GREATEST loss of vitamins?

    A. Washing the vegetables before cooking

    B. Adding a pinch of salt at the end

    C. Overcooking and discarding the cooking water

    D. Serving the vegetables while still warm

    (1 mark)

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11. Question 11

    1 mark

    Why should vegetables be washed before they are cut rather than after cutting?

    A. To increase the weight of the vegetables

    B. To make cutting easier

    C. To prevent water-soluble nutrients from dissolving away

    D. To remove the natural colour

    (1 mark)

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12. Question 12

    1 mark

    A family stores maize grains in an airtight container with a preservative to keep them for months. This helps conserve the nutrients by:

    A. Increasing the moisture content

    B. Speeding up germination

    C. Keeping out moisture and pests

    D. Adding proteins to the grains

    (1 mark)

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13. Question 13

    4 marks

    Describe how drying can be used to conserve the nutrients in vegetables such as managu, and state one advantage of this method to a Kenyan household.

    (4 marks)

    Marking scheme

    Description (2 marks): the vegetables are washed, sometimes blanched, then spread thinly and dried in the sun or in a drier until moisture is removed so micro-organisms cannot grow; the dried vegetables are stored in clean airtight containers. Advantage (any 1, 2 marks): allows vegetables to be kept for a long time / for use during the dry season; reduces wastage; provides food when fresh vegetables are scarce; can be sold for income.

14. Question 14

    1 mark

    A learner peels potatoes very thickly before cooking. What is the main disadvantage of this practice?

    A. Loss of nutrients found just beneath the skin

    B. Increased cooking time only

    C. Better taste of the potatoes

    D. Improved colour of the potatoes

    (1 mark)

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15. Question 15

    4 marks

    Njoki notices that her family's vegetables always look faded and taste bland after cooking.

    (a) State two mistakes she may be making that lead to loss of nutrients.

    (b) Suggest two ways she can improve.

    (4 marks)

    Marking scheme

    (a) Any 2 (1 mark each): boiling in too much water; overcooking / cooking too long; cutting vegetables too small; washing after cutting; discarding cooking water. (b) Any 2 (1 mark each): cook for a shorter time; use little water and cover the pot; wash before cutting; steam instead of boiling; serve immediately.

16. Question 16

    1 mark

    A learner is told to peel potatoes for ugali accompaniment in a way that conserves nutrients. Which peeling practice should the learner follow?

    A. Peel very thick layers off each potato

    B. Peel as thinly as possible since many nutrients lie just under the skin

    C. Leave the potatoes to dry in the sun after peeling

    D. Cut the potatoes and soak them for several hours

    (1 mark)

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17. Question 17

    4 marks

    State two water-soluble nutrients that are easily lost during cooking and explain why using a small amount of water helps to conserve them.

    (4 marks)

    Marking scheme

    Water-soluble nutrients (any 2, 1 mark each): vitamin C; B-group vitamins (e.g. thiamine); some mineral salts. Explanation (2 marks): these nutrients dissolve into the cooking water; using little water means less of the nutrient dissolves out and the water can be consumed with the food, so fewer nutrients are lost.

18. Question 18

    1 mark

    To conserve nutrients when preparing fruits for a fruit salad, they should be cut:

    A. Just before serving

    B. And exposed to direct sunlight

    C. Several hours in advance

    D. And left soaking in water overnight

    (1 mark)

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19. Question 19

    1 mark

    A processor stores fresh milk by heating it briefly then cooling it quickly to destroy harmful micro-organisms. This method of conserving milk is known as:

    A. Salting

    B. Pasteurisation

    C. Fermentation

    D. Smoking

    (1 mark)

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20. Question 20

    3 marks

    Explain three ways in which a household can conserve the vitamins in green leafy vegetables during preparation and cooking.

    (3 marks)

    Marking scheme

    Any 3 (1 mark each): Wash vegetables before cutting them (avoid losing water-soluble vitamins); cut into large pieces rather than very small ones; cook for a short time / avoid overcooking; use little water and reuse the cooking water in soups/stews; cover the pot / steam instead of boiling in plenty of water; serve immediately after cooking rather than reheating.

21. Question 21

    3 marks

    Give three reasons why food should be conserved rather than allowed to go to waste in a home.

    (3 marks)

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