Flashcards in Fish and Shellfish Deck (55)
What is seafood?
aquatic animals for human consumption
true fish + shellfish
What are the commonly marketed fish products? (6)
The top fish producing country is:
What are the various animal types harvested for seafood?
- bony fish
- cartilagenous fish (shark, skate)
What are the flavor classifications of fish? give some examples
Mild: Cod, Halibut, Porgie
Medium: Shrimp, Lobster, Skate
Strong: Salmon, Mackerel, Sardines
What are the factors that affect fish composition? (8)
- population density
- migratory or spawning behaviour
Most fish sold as food is in ____ form, followed by _____.
frozen (24%); fresh (22%)
Wild harvest of fish was increasing, but now has stabilized around ___. Why?
What source of fish in increasing?
- Regulations (government limit)
- Depletion of stocks (overfished, few left)
Aquaculture (farmed fish) is increasing
What are some non-food uses of fish? (5)
Name the fins on a teleost fish:
on back: Dorsal, Adipose (near tail)
Belly: Pectoral (front), Pelvic, Anal
How does fat distribution differ in fatty and lean fish? What types of lipid predominate?
fatty: fat throughout flesh
lean: fat accumulates in liver/gut
mostly TG, also PL in skin and membranes
fish is about ___% protein, which is comparable to ____.
What component shows the most variation in fish? What other component will also vary, and what causes these variations?
Lipids, also protein
spawning/migration -> use energy, lower lipid/protein
increase in period of heavy feeding
Describe the 2 layers of fish skin:
outer layer: epidermis
- high moisture
- glands make mucus (MUCOPOLYSACCARIDES)
inner layer: dermis
- conn tissue fibres
- pigment cells (GUANOPHORES)
The main sugars of mucopolysaccharides that form the fish slime layer are: (2)
Fish oil is an excellent source of ____ PUFAs, but what problem does this cause?
omega 3 (good for health!)
prone to oxidative rancidity
What is the main cause for the rapid bacterial decay of fish?
The microflora present on scales/skin, resistant to low temperatures
Name the 3 protein types in fish, and their proportions.
Sarcoplasmic (dissolved) - 20-30%
Myofibrillar (muscle, salt-soluble): 65-75%
Stromal (insoluble) : 3-10%
actin, myosin, and troponin are all ____ proteins, while collagen is a ____ protein.
how do the proportions of fish protein types compare to that in mammals?
How does this affect the fish meat?
Less stromal: don't need as much connective tissue since water can support weight
More myofibrillar: need strong muscle for swimming
sarcoplasmic stays the same (enzymes, etc)
fish is more tender than meat, since less sarcoplasmic
What type of protein is Mb?
How do fish myofibrillar proteins compare to mammalian counterparts?
more myofibrillar, but individual proteins in same proportion
More easily denatured by heat
True/False: the sarcoplasmic protein proportions and types remain fairly constant among all fish.
False: different patterns can be seen, and used to identify fish
What sarcoplasmic fish protein is different from the mammal version? This protein is concentrated in ______.
Mb - fish has cysteine, mammal does not
concentrated in dark muscle
Fish protein generally has higher levels of what AAs, compared to mammals? This means that it would pair well with:
lysine, cysteine, methionine
cereals (low in those AAs)
___, a very basic non-protein AA, is found in fish and has antimicrobial properties
The main connective tissue proteins in fish are:
collagen (90%), elastin
How does the final meat yield from fish compare to mammals?
lower yield after removal of head, guts, tail, etc (lose up to 50%)
mollusc/crustacea lose even more (over 50%)
but less losses during cooking
True/False: fish contain all the essential AAs.
True (like all animal protein)