Lab 9: Omega-3-Rich Food Choices and Preparation

Question 1

What types of fish are good sources of w3 fatty acids?

Answer 1

Oily fish that live in cold water

Question 2

What are some examples of fish high in w3?

Answer 2

ex. Salmon, lake trout, herring, mackerel, sardines

Question 3

Why is fish recommended in the diet?

Answer 3

Lower fat / similar protein content to poultry and other meats.

Question 4

Why is fish more tender than other meats?

Answer 4

It has a smaller quantity of connective tissue.

Question 5

What will happen to fish if overcooked?

Answer 5

Will quickly dry out, shrink, toughen and alter it’s flavor.

Question 6

What causes the protein in fish to coagulate?

Answer 6

Proteins are easily coagulated with heat or acid.

Question 7

What are some common seasoning for fish?

Answer 7

Lemon, Lime, Garlic, Parsley, Ginger, Lemongrass, Chives, Paprika, Tarragon, Celery.

Question 8

What plant sources are high in alpha-linolenic acid?

Answer 8

Walnut, Flaxseed, Hemp.

Question 9

What is alpha-linolenic acid used for?

Answer 9

Converted to omega-3 fatty acids in the body.

Question 10

Good uses for ground flax and hemp seeds?

Answer 10

Used as topping

Added to cereals, cookie/ muffing mixes, soups, sauces, meat loafs.

Question 11

Good uses for flax seed oil and hemp seed oil?

Answer 11

Used in dressings.

Question 12

How is it that eggs are a good source of omega-3 fatty acids?

Answer 12

Enriched, by feeding hens linseed.

Question 13

What factors effect egg protein coagulation?

Answer 13

Temperature
Concentration
Acid
Salt
Sugar

Question 14

What temperature causes egg white to coagulate?

Answer 14

62-64 C

Question 15

What temperature causes egg yolks to coagulate?

Answer 15

65-70 C

Question 16

What happens to egg proteins when slowly heated?

Answer 16

They denature, and tangle loosely with water between the strands.

Question 17

What happens to egg proteins when cooked for too long or at high heats?

Answer 17

They denature, they mesh tightly. Less water between the strands: cause them to be tough and leathery,

Question 18

What raises the temp at which egg proteins coagulate?

Answer 18

Diluting egg proteins (with water/other ingredients)

Sugar

Question 19

What happens to egg whites when acid is added?

Answer 19

Egg white = naturally alkaline
Adding acid brings pH near isoelectric point
Reduce stability = more sensitive to denaturing

Question 20

What does sugar do to egg proteins?

Answer 20

Rises coagulation temp.

more tender mixture

Question 21

What temperature is ideal for cooking eggs (hard boiled)?

Answer 21

Simmer under 85 C

Never boiled.

Question 22

What is the result of overcooking a boiled egg?

Answer 22

Egg white becomes tough and rubbery.

Produce grey-green film at interface of yolk and white.

Question 23

What causes the grey-green film between the egg yolk and white?

Answer 23

Reaction of Iron (yolk) and sulfur (white)
Making Ironsulfide

(reaction favored in older eggs)

Question 24

How can you minimize the grey-green film in a boiled egg?

Answer 24

Quickly cool the egg in cold water after cooking.

Question 25

Can eggs be frozen?

Answer 25

Yes, must be uncooked, no shell, in sealed container.

Question 26

How would you freeze egg whites?

Answer 26

As is.

In sealed container (leave space for expansion)

Question 27

1 egg white =

Answer 27

2 tbsp frozen eggwhites

Question 28

1 egg yolk =

Answer 28

1 tbsp frozen egg yolk

Question 29

1 whole egg =

Answer 29

3 tbsp frozen eggs

Question 30

How would you freeze egg yolks?

Answer 30

Beat: 1/4 cup yolks (about 4)

: 1/8 tsp salt/sugar/cornstarch

Question 31

Why is salt added to egg yolk when frozen?

Answer 31

To prevent clumping and lower coagulation temp.

Question 32

How would you freeze whole eggs?

Answer 32

Gently beaten in air tight container.

Question 33

Should cooked eggs be frozen?

Answer 33

No! they become hard and rubbery.

Question 34

What lowers the temp at which egg proteins coagulate?

Answer 34

Acidic water (by adding lemon of vinegar to water)
Salt (added to water)