Lab 9: Omega-3-Rich Food Choices and Preparation Flashcards
What types of fish are good sources of w3 fatty acids?
Oily fish that live in cold water
What are some examples of fish high in w3?
ex. Salmon, lake trout, herring, mackerel, sardines
Why is fish recommended in the diet?
Lower fat / similar protein content to poultry and other meats.
Why is fish more tender than other meats?
It has a smaller quantity of connective tissue.
What will happen to fish if overcooked?
Will quickly dry out, shrink, toughen and alter it’s flavor.
What causes the protein in fish to coagulate?
Proteins are easily coagulated with heat or acid.
What are some common seasoning for fish?
Lemon, Lime, Garlic, Parsley, Ginger, Lemongrass, Chives, Paprika, Tarragon, Celery.
What plant sources are high in alpha-linolenic acid?
Walnut, Flaxseed, Hemp.
What is alpha-linolenic acid used for?
Converted to omega-3 fatty acids in the body.
Good uses for ground flax and hemp seeds?
Used as topping
Added to cereals, cookie/ muffing mixes, soups, sauces, meat loafs.
Good uses for flax seed oil and hemp seed oil?
Used in dressings.
How is it that eggs are a good source of omega-3 fatty acids?
Enriched, by feeding hens linseed.
What factors effect egg protein coagulation?
Temperature Concentration Acid Salt Sugar
What temperature causes egg white to coagulate?
62-64 C
What temperature causes egg yolks to coagulate?
65-70 C
What happens to egg proteins when slowly heated?
They denature, and tangle loosely with water between the strands.
What happens to egg proteins when cooked for too long or at high heats?
They denature, they mesh tightly. Less water between the strands: cause them to be tough and leathery,
What raises the temp at which egg proteins coagulate?
Diluting egg proteins (with water/other ingredients)
Sugar
What happens to egg whites when acid is added?
Egg white = naturally alkaline
Adding acid brings pH near isoelectric point
Reduce stability = more sensitive to denaturing
What does sugar do to egg proteins?
Rises coagulation temp.
more tender mixture
What temperature is ideal for cooking eggs (hard boiled)?
Simmer under 85 C
Never boiled.
What is the result of overcooking a boiled egg?
Egg white becomes tough and rubbery.
Produce grey-green film at interface of yolk and white.
What causes the grey-green film between the egg yolk and white?
Reaction of Iron (yolk) and sulfur (white)
Making Ironsulfide
(reaction favored in older eggs)
How can you minimize the grey-green film in a boiled egg?
Quickly cool the egg in cold water after cooking.
Can eggs be frozen?
Yes, must be uncooked, no shell, in sealed container.
How would you freeze egg whites?
As is.
In sealed container (leave space for expansion)
1 egg white =
2 tbsp frozen eggwhites
1 egg yolk =
1 tbsp frozen egg yolk
1 whole egg =
3 tbsp frozen eggs
How would you freeze egg yolks?
Beat: 1/4 cup yolks (about 4)
: 1/8 tsp salt/sugar/cornstarch
Why is salt added to egg yolk when frozen?
To prevent clumping and lower coagulation temp.
How would you freeze whole eggs?
Gently beaten in air tight container.
Should cooked eggs be frozen?
No! they become hard and rubbery.
What lowers the temp at which egg proteins coagulate?
Acidic water (by adding lemon of vinegar to water) Salt (added to water)
