Fish and Shellfish Flashcards
What is the most consumed fish in Canada?
Salmon
How often do Canadians eat finfish?
3.7 x per month
How often do Canadians eat shellfish?
1.9 x per month
What is the difference between finfish and shellfish?
Finfish: vertabrate, skeleton
Shellfish: invertabrate
How much fat do fatty fish contain?
Moderate fat: 5-10 g
Higher fat: > 10 g
Define caviar or roe.
Eggs of vertebrae fish
How much fat do lean fish contain (in 3-ounces of cooked fish)?
Very low in fat: < 2.5 g
Low in fat: 2.5 to 5 g
What does the Canadian Food Inspection Agency inspect?
- federally registered fish and seafood establishments
What is caviar/roe high in? How much?
cholesterol (94mg/TBSP)
How much water does fish contain?
65-85%
How much protein does fish contain? What essential amino acids?
- 15-20%
- Lysine and methionine
How much fat does fish contain?
1-15%
How much carbohydrate does fish contain?
0%
What are the three ways to classify fish?
- Fat content
- Texture
- Flavour
How much carbohydrate does fish contain?
Insignificant
What is surimi?
Alaskan Pollack (cheap) -> cheap, deboned, washed, strained - shaped into shrimp, scallops, lobster tail
Name the 2 organizations responsable of the fish industry in Canada.
- Fisheries and Oceans Canada
- Canadian Food Inspection Agency
Who regulates seafood grading? What does grading depend on?
- CFIA
- Size, weight, colour, uniformity
Are the grading the methods the same for all fish?
No, each fish has a different grading method
Differentiate the grading for Atlantic Smelts and Whitefish.
Atlantic Smelts: length
Whitefish: weight
Define a whole fish.
Intact body
Define a drawn fish.
Inner organs removed
Define dressed or pan-dressed fish
Inner organ, head, tail, fin and scales removed
Define steaks.
Sliced from the top
Define single fillet.
Sliced length wise from head to tail
Define sticks.
Sliced or minced and shaped
Define butterfly fillet.
Steak from large fish
How do you determine the freshness of a fish? (4)
1) Sniff test (smell the gut of the fish, sea = fresh, ammonia = not fresh)
2) Red grills (brown is not good)
3) Bulging and jet black eyes with translucent cornea
4) Bright and shiny skin with tight scales, belly free of swelling (bacteria produces gases), firm and stiff body (rigor mortis)
When is the best time to consume a fish? Why?
During rigor mortis
Water will be bound to proteins (juicier, better texture, better flavour)
Are shellfish perishable?
Highly
How do you know if mollusks are alive?
Little bit opening, tap on the shell, if it closes tightly it means it is alive
You should buy them live
Why should lobster be cooked alive?
- Bacteria in the flesh of the lobster, the bacterias proliferate as soon as the lobster dies and starts to produce toxins
- Bacteria dies during cooking, but toxins stay (so it needs to be cooked alive)
What do you have to remove when you cook sand-vein?
Sand vein, if you keep it it will have a sandy taste
Why do shrimps become orange?
When the shrimp is cooked there will be denaturation of the proteins and will release carotenoids
How can you purchase shrimp?
- Fresh/frozen
- Raw/cooked
- Shell-on/peeled
How is fish muscle arranged? What is it separated by?
- Arranged in layers of short fibers < 1 inch in length (myotomes)
- Separated by very thin sheets of CT (myocommata)
What is responsable for the tenderness of the fish?
Fish structure (collagen is low), causes fish to flake ALSO less hydroxyproline (amino acid)
What is the collagen content in fish?
3% with less hydroxyproline
- Less hydroxyproline (amino acid) and less collage = 2 reasons why fish are more tender than meat
What other ability does the muscle protein of fish possess?
Gel forming ability
Can the fat content in fish vary?
Yes depending on starved or fed state
What happens if the fat content decreases in fish?
Water will increase
What types of fibres do red or dark flesh fish have?
Slow twitch fibres
What are slow twitch fibres used for?
Long distance swimming
What types of fibres do white fish have?
Fast twitch fibres
What are fast twitch fibres used for?
Quick burst of speed or brief duration
What other pigments are in fish?
Myoglobin and carotenoids
Why are carotenoids in fish?
Feed on insects and crustacean containing those pigments
What does Canada’s Food Guide recommend in terms of fish?
2 servings of fish/week
How many grams of protein is in 100 grams of salmon? In 100 grams of chicken breast?
Salmon: 25.44 grams
Chicken: 27.39 grams
almost the same amount of protein
How does saturated fat and omega-3 fatty acids compare in chicken and salmon?
Less saturated fats and more omega-3s in salmon
What does the Dietitians of Canada recommend to aim for in terms of EPA and DHA per day?
0.3 to 0.45 g of EPA and DHA per day
Why are Omega-3 Fatty acids so important?
- Essential fatty acids
- Immune system response
- Inflammatory response
- Fetal development (neuronal, retinal)
- Cardiovascular health
- Weight management
- Cognitive function (Alzheimer’s)
- Healthy aging process
What % of the brain is made up from fat? What % of that is made up from DHA?
60% of brain is made up from fat
30% of that is made up from DHA
Name the 3 hazards in eating fish
1) Mercury
2) Histamine poisoning
3) Escolar or butterfish
Why is mercury hazardous?
Toxic to nervous system
What types of fish contain high mercury?
Fresh/frozen tuna, shark, swordfish, marlin
Does canned mercury apply to canned tuna?
No, generally younger and smaller and have less mercury than fresh or frozen
- EXCEPT IF IT IS ALBACORE TUNA (++ MERCURY)
What do histidine decarboxylase enzymes do?
Transform histidine from the skin, grills, gut of fish into histamine
What is the problem with histamine?
Responsable for allergic reactions (tingling, burning, swelling, low BP, headaches, vomiting)
Are the types of fish that are popular in Canada high in mercury?
No, they are low
What is the problem with escolar or butterfish?
Indigestible oil made up of high amounts of wax esters gempylotoxin
- Diarrhea (short-term)
Name 4 dry-heat ways to preparation techniques.
- Baking
- Broiling
- Grilling
- Frying (Sautéed, deep-fat fried)
Name 4 moist-heat preparation techniques.
- Poaching
- Simmering
- Steaming
- Microwaving
What heat should you use when you bake fish?
180-200 oC
How do you prepare fish before baking?
Rinse, pat-dry
How long should you bake fish?
10 minutes/inch of thickness
How does baked fish end up?
Easily flakes, opaque whitish, tender moist
What happens when you overheat baked fish?
Overheating -> tightens protein bonds -> protein mesh shrinks -> water squeezed out -> tough, dry fish flesh
At what temperature should you poach fish?
Low temp: 71-82 oC
Never boiling liquid
What is the advantage of poaching fish?
Retain flavour & moisture
Name 4 ways to store fish.
Fresh, frozen, canned or cured
Is fish perishable?
Yes, highly, precaution to ensure freshness
When is fresh fish best consumed?
1-2 days after purchase
When should evisceration occur (remove all the gut)?
Immediate
Where should fish be stored in the refrigerator?
Store In coldest portion of refrigerator <4°C
Why should fresh fish be wrapped tightly?
Omega-3 fatty acids will become oxidized and prevent odours from coming in contact with other foods
Where can fresh shellfish be kept? Why?
Fresh shellfish can be kept alive in cool salty wet environment
Why do live oysters, clams and mussels need to be well aerated?
They need to breathe
How long do frozen fish last?
Up to 9 months
Do lean fish or fatty fish last longer?
Lean fish last longer
What are the consequences of freezing fish?
- Reduction In Quality
- Dryer (keep airtight)
- Tougher (low water holding capacity)
- Less flavorful
How long do canned fish last?
Up to 12 months
How can cured fish be stored?
Refrigerated
Frozen
Canned
What are fresh water finfish? Which one is fatty?
Catfish, Perk, Pike
Fatty: Lake Trout
What are lean salt water finfish?
Halibut Haddock Cod Swordfish
What are fatty salt water finfish?
Mackerel
Herring
Atlantic
Salmon
What are crustaceans (shellfish)?
Crab
Crayfish
Lobster
Shrimp
What are bivalve mollusk (shellfish)?
Clam Mussel Oyster Scallop
What are univalve mollusk (shellfish)?
Abalone Snail
What are cephalopod (shellfish)?
Octopus
Squid
Name fish that are very low in fat.
-Clam -Haddock -Shrimp -Squid
Name fish that are low in fat.
-Catfish -Oysters -Pink Salmon -Sea Trout
Name fish that are moderate in fat.
- Herring
- Spanish Mackerel
- Atlantic Salmon
- Lake Trout -Whitefish
Name fish that are high in fat.
- Atlantic Mackerel
- King Salmon
What are the two types of shellfish?
Crustacean and mollusk
What are myotomes?
Layers of short fibres in fish muscles
What are myocommatas?
Large sheets of very thin connective tissue separating the myotomes
