Chapter 4: Food comodities Flashcards
(332 cards)
Classify fish
3
- white fish
- oily fish
- shellfish
List examples of white fish
3
- cod
- whiting
- place
List examples of oily fish
3
- salmon
- tuna
- mackerel
List examples of shellfish
3
- lobster
- muscles
- crab
List the nutrients present in fish
6
- protein
- fat
- carbohydrates
- vitamins
- minerals
- water
Describe the nutritive value of protein in fish?
3
- it is of high biological value
- the protein actin and myosin are present in the myomers
- the protein collagen is found in the connective tissues
Describe the nutritive value of fat?
3
- in the form of omega 3
- the omega 3 fatty acids involve ERA and DHA
- small amounts of cholesterol are present
Describe the nutritive value of carbohydratesin fish
1
-none present
Describe the nutritive value of vitamins in fish
3
- B
- A
- D
Describe the nutritive value of minerals in fish
3
- iodine
- iron
- calcium
Describe the nutritive value of water
2
- depends on fat content in fish
- i.e. if water content is high fat content will be low
What makes up the structure of a fish?
4
- myomers
- connective tissue
- fat
- outer layer
Describe how myomers make up the structure of a fish.
3
- short, thick, fibres arranged in a broad vertical bond
- contains the proteins actin and myosin
- contains minerals, vitamins, water and extractives
Describe how connective tissues make up the structure of a fish
(5)
- holds myomers in place
- the tissue contains the protein collagen
- fish has less connective tissue than meat
- contains no elastin
- therefore it is more tender and easier to digest and it takes less cooking time
Describe how fats make up the structure of a fish
2
- invisible in oily fish
- dispersed between the myomers and the connective tissue
Describe how the outer layer makes up the structure of a fish
(1)
-it is waterproof and scally
List some guidelines for buying and storing fish
6
- date
- cost
- quality: should have scales, big bulgy eyes, not slimy
- shells should be closed
- no strange smell
- store on ice in the bottom of the fridge (2-5°C)
Explain how oxidative rancidity causes the spoilage of fish
3
- oils in oily fish react with oxygen
- oxygen combines with the carbon in the double bonds along the unsaturated fatty acid chain
- this causes the fish to go off
Explain how enzymes cause the spoilage of fish
3
- naturally present in fish,
- cause it’s flesh to deteriorate even at low temperatures
- to slow this down fish can be placed on ice or in a fridge
Explain how bacteria cause the spoilage of fish
4
- fish use up the glycogen in their muscles and liver when they get caught
- this results in little glycogen left to be converted to lactic acid to preserve the fish
- this causes rapid deterioration by bacterial action
- this produces a strong smelling compound called trimethylamine
List the effects of cooking on fish
5
- protein coagulates
- b vitamins are lost
- colour change
- bacteria is destroyed
- if over-cooked, fish is rubbery
What is nutritive value?
1
-all the nutrients that are present in a food
Describe the nutritive value of protein in eggs
3
- high biological value
- ovalbumin and globulin are present in the egg white
- livetin and vitelin are present in the yolk
Describe the nutritive value of fat in eggs
3
- saturated fat present in the yolk
- cholesterol present in the yolk
- egg white is fat free