Chap 9 Flashcards
Most consumed fish in Canada + how often is fish consumed in Canada
Salmon. 4x month finfish, 2xmonth shellfish
Type of fats and fish
Very low fat: Tuna (yellowfin, skipjack), Haddock, clam, shrimp. <2,5g per 3ounces
Low fat: Catfish, oysters, pink salmon, sea trout.
Moderate: Atlantic salmon, lake trout, herring, spanish mackerel
High: Atlantic mackerel, king salmon.
Caviar or roe
Eggs of vertebrate fish. high in cholesterol, highly perishable, high in salt(preservative), pasteurized to extend shelf life, many species: herring, pacific salmon, white fish, trout.
Surimi
Alaskan Pollack. Skinned, debonned, minced, washed, strained, shaped into.
Fish industry in Canada
Fishing licences, fishery openings and closures, fishery quotas and requirements, reports and allowable catch information, strong mandatory inspection programs for federally registered fish and seafood establishments, analyze acceptable quality, safety and identity of domestic seafood or fish
FISH- Grading
Size, color, uniformity, weight
Fish - Purchasing, type of cut
Whole, drawn (inner organs removed), dressed (inner organs, head, tails, fin, scales removed), steaks (sliced from the top), single filet (sliced lengthwise from head to tail), stick (sliced or minced and shaped), butterfly filet (steak from large fish)
Fish freshness
ammonia, bloated (bacterial produce gas), opaque eyes, non red gills, right after rigor mortis is the best time to consume a fish, afterwards it deteriorates, flesh is juicier due to water holding by proteins= bad
Purchasing shellfish
Highly perishable, alive or processed
Why cook lobster alive
They have a harmful bacteria and when the lobster is dead, it multiplicates really fast and it cannot be killed with cooking.
How do we know if mollusks are dead and should not be bought?
- They don’t close
- They are broken
- They float
- They have a decaying odor
Shrimps. What part should we remove?
Sand vein, it doesnt taste good and it’s a copying mecanism
Why are fish tender?
- Less collagen (3-15%), more delicate less tough
- Less hydroxyproline, so collagen breaks down at a lower temp = soft, gel-like texture
- Muscle structure, shorter fibers. flakes off easily (myotome separated by myocommata) less than an inch
Fish composition
Water: 65-80%
Proteins: 15-20%
Lipids: 1-15% (lean 1-5: shellfish,haddock,sole) (medium5-10: halibut, turbot)(high fat10-15: salmon, herring)
CHO: almost none, little bit in invertebrates
Pigments: dark,red: long distance, slow twitch fibers: salmon
white: short distance, burst of speed, short distance, fast twitch fibers: sole
Myoglobin
Carotenoids, astaxanthins in pink salmon and trout (feed on insects that have these)
Why are fish healthy?
High quality proteins, lean meat, omega 3 (epa, dha), vit A D(fat soluble ;) Vit b, P Ca I fluorine.
Omega-3
Dha, Epa. altantic salmon, herring. Immune system response, inflammatory response, fetal development, cardiovascular health, cognitive functions (alzheimer)
Mercury
Toxic for nervous system. Fish popular in Canada (fatty fish) are low. Tuna, shark, swordfish, king mackerel, tilefish, marlin, orange roughy, escolar. Canned light tuna= younger = less mercury accumulated
Avoid ALBACORE TUNA!!
Salmon, herring, anchovies (canned)
Chemical intoxication
Allergic reactions occurs when fish is not chilled immediatly after being cought. Histidine turns inot Histamine.
Baking fish
180-200 celsius, 10min/inch of thickness, easily flakes, whitish opaque. Overheating: tighens proteins bonds, squeeze water out, tough dry flesh
Poaching fish
71-82 celsius, never boiling liquid, retain flavor and moisture
Consuming fish, tips for freshness
Best consumed 1-2 days after purchase, Evisceration should be immediate, store less than 4celsius, wrap to prevent exposure to oxygen and odor contamining other food.
Reasons Grading in Canada
Consistent product quality
Establish prices
Facilitate trades
Consumption and Storage shellfish
Consumed the day of purchase, can be kept in cool salty wet environment, clams, mussels, oysters = well aerated
Freezing fish
Lean fish = up to 9 months, longer than fatty because fat is oxidized in fatty fishes. BUT : drier, tougher, less flavourful
All atlantic salmon is
Farmed and fed fish oils to keep omega 3 content
Alternatives to salmon
Atlantic char, rainbow trout
2 types of farmed fisheries
Recirculating aquaculture system and net-penned salmon
Sources of Saturated fat
animals, chocolate, coconut oil, palm oil, vegetable shortening
Sources of monounsaturated fat
Avocado, olive, canola oil.
Sources of polyunsaturated fat
Vegetable oils (canola, sunflower, safflower, soybeans), almonds, walnuts, pecans
Phosphoglycerolipids are good
emulsifying agents. (lecithin in egg yolk)
Butter emulsifies because it contains
water molecules trapped with the fat molecules
More refined oils contain more
waxes
Oils with higher smoking point
Avocado oil, soybean oil
Oils recommended for frying because of
Delicate flavour and high smoking point. Canola, peanut, sunflower, safflower, cottonseed.
Storage and shelf life of oil
Monounsaturated: 1year
Polyunsaturated: 6months
Definition of Hydrolytic rancidity
Exposure to water, catalyzed by heat and lipase enzymes. Ex: deep-frying, butter left at room temperature.
Definition of Oxidative rancidity
Presence of oxygen. More unsaturated = more sensible.
- Initiation: free radical is formed, light, heat, salt
- Propagation: oxygen reacts with free radical and forms peroxide free radical
- Termination: no more double bonds to react with oxygen
Use of __________ to prevent rancidity
Antioxydants.
- Oxidize themselves
- Give H to FA
- Sequestering metals
ex: vit c, vit e, sulfites, flavonoids, betacarotenes
Canada food guide recommends
2-3 tbsp unsaturated fatty acids per day.
Oil extraction methods
Chemical: using solvents (hexane)
adv: highest yield, most affordable.
disadv: lower quality, loss of nutrient because of heating the oil
Mecanical: Cold-pressed: highest quality oil, more expensive
Refining oil
Remove undesirable components. higher smoking point :)
5 steps: degumming, neutralization, bleaching, deodorization, winterization
Unrefined oil may contain
pigments, metal, waxes, odors
Cause and how : Modification of fats
More stable, more easier to consume or cook with, better shelf life
Hydrogenation, interesterification, winterization, fractionation
Hydrogenation
To harden vegetable oils
Interesterification
Uses enzymes. Modification of arragement of fatty acid of triglycerides on glycerol backbone. Change in the physical properties without creating trans. (make all the FA in the oil, the same!)
Winterization
Oil is kept at low temperature, solid and liquid separated
Fractionation
Same as Winterization but better technique.
Uses of fat in cooking
Flavour, Heating agent, emulsifier, texture, satiety, nutrients, shortening
Low fat cooking methods
- non stick pan, parchment paper
- moist heat methods (steaming, poaching) of broiling instead of frying
- choice of ingredients (oil, meat(cut), replacements (mashed bananas), less is more(cheese))
- Trim visible fat
Replacement of fat in baking
Bananas, beans, tofu, applesauce, shredded zucchinis.
Coconut oil
Medium chain fatty acids (max is C12) so easily metabolized, doesnt have to be de-packed. Saturated fat 87%
