Topic 5: Part E

Question 1

Proteins

Answer 1

• found in every living cell

- essential for human life and growth

Question 2

Proteins plays several important roles in food such as …

Answer 2

water binding, gel formation, thickening, emulsion and foam formation and Maillard reaction

Question 3

Enzymes

Answer 3

specialized protein molecules that catalyze a number of important reactions in foods

Question 4

Protein is a …

Answer 4

chain of amino acids joined together by a peptide bond

Question 5

Proteins contain…

Answer 5

carbon, hydrogen, oxygen, nitrogen and sulphur

Question 6

Amino acids are joined by peptide bonds to produce long (straight) chains that..

Answer 6

constitute the primary structure of proteins

Question 7

Secondary structure

Answer 7

coiling fo the long chain

Question 8

Tertiary structure

Answer 8

the coils may fold back on themselves, suavely in an irregular pattern to form a more compact and globular form

Question 9

Quaternary structure

Answer 9

some proteins have these, which occurs when globular proteins combine with each other to form an even more complex structure

Question 10

Structure fo a protein is critical too..

Answer 10

its function in a living cell or in food preparation (won’t be the same if something is off)

Question 11

How many different amino acids are used as building blocks to form proteins

Answer 11

20

Question 12

How many amino acids are considered essential in human nutrition

Answer 12

9

Question 13

Balance of amino acids in a protein determines ..

Answer 13

its biological value an nutritional quality

Question 14

Proteins with high biological value (complete proteins) contain ..

Answer 14

adequate amounts of essential amino acids

Question 15

Foods with high biological value proteins include ..

Answer 15

animal products

Question 16

Different plant proteins can be combined to provide diets with ..

Answer 16

high biological value (mixture of legumes and cereals) **important for vegetarian lifestyle

Question 17

Cooking with moist heat (Steaming, poaching) improves..

Answer 17

protein digestibility

Question 18

Dry heat cooking can make protein ..

Answer 18

less digestible

Question 19

2 characteristics of high quality proteins (egg whites)

Answer 19

• contain the essential amino acids proportional to the body need for them
• are digestible so that sufficient numbers of the amino acids reach the body cell

Question 20

Amino acids most easily digested and absorbed

Answer 20

• animal protein: >90%
• legumes: 80-80%
• grain/plant proteins: 70-90%

Question 21

Essential amino acids

Answer 21

• lysine
• tryptophan
• phenylalanine
• methionine
• leucine
• isoleucine
• threonine
• valine
• histidine (only for infants)*