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Flashcards in Fish and Shellfish Deck (55)
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1

What is seafood?

aquatic animals for human consumption
true fish + shellfish

2

What are the commonly marketed fish products? (6)

Fresh
Frozen
Smoked/salted/marinated
Canned
Fish Meal
Fish Oil

3

The top fish producing country is:

China

4

What are the various animal types harvested for seafood?

vertebrates:
- bony fish
- cartilagenous fish (shark, skate)
invertebrates:
- mollusc
- crustacean
- echinoderms

5

What are the flavor classifications of fish? give some examples

Mild: Cod, Halibut, Porgie
Medium: Shrimp, Lobster, Skate
Strong: Salmon, Mackerel, Sardines

6

What are the factors that affect fish composition? (8)

- species
- diet
- season
- age
- sex
- habitat
- population density
- migratory or spawning behaviour

7

Most fish sold as food is in ____ form, followed by _____.

frozen (24%); fresh (22%)

8

Wild harvest of fish was increasing, but now has stabilized around ___. Why?

What source of fish in increasing?

95 tonnes
- Regulations (government limit)
- Depletion of stocks (overfished, few left)

Aquaculture (farmed fish) is increasing

9

What are some non-food uses of fish? (5)

Fertilizer
Feed
Supplements
Gelatin (glue)
Cosmetics

10

Name the fins on a teleost fish:

on back: Dorsal, Adipose (near tail)
Tail: Caudal
Belly: Pectoral (front), Pelvic, Anal

11

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

12

fish is about ___% protein, which is comparable to ____.

16-21%
beef

13

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

14

Describe the 2 layers of fish skin:

outer layer: epidermis
- high moisture
- glands make mucus (MUCOPOLYSACCARIDES)
inner layer: dermis
- scales
- conn tissue fibres
- pigment cells (GUANOPHORES)

15

The main sugars of mucopolysaccharides that form the fish slime layer are: (2)

glucosamine, galactosamine

16

Fish oil is an excellent source of ____ PUFAs, but what problem does this cause?

omega 3 (good for health!)
prone to oxidative rancidity

17

What is the main cause for the rapid bacterial decay of fish?

The microflora present on scales/skin, resistant to low temperatures

18

Name the 3 protein types in fish, and their proportions.

Sarcoplasmic (dissolved) - 20-30%
Myofibrillar (muscle, salt-soluble): 65-75%
Stromal (insoluble) : 3-10%

19

actin, myosin, and troponin are all ____ proteins, while collagen is a ____ protein.

myofibrillar
stromal

20

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

21

What type of protein is Mb?

sarcoplasmic

22

How do fish myofibrillar proteins compare to mammalian counterparts?

more myofibrillar, but individual proteins in same proportion
More easily denatured by heat
Fast hydrolysis
(easy digestibility)

23

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

24

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

25

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)

26

___, a very basic non-protein AA, is found in fish and has antimicrobial properties

protamine

27

The main connective tissue proteins in fish are:

collagen (90%), elastin

28

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

29

True/False: fish contain all the essential AAs.

True (like all animal protein)

30

What are the major NPNs found in fish? (6)

N containing extractives:
- volatile bases (TMAO, NH3)
- urea (cartilagenous fish)
- nucleotides/purines
- free AA
- creatine