Fish Processing Flashcards
How can fish be processed?
3
Freezing
Canning
Smoking
Explain the process of freezing fish.
Fish can be frozen by commercial blast freezing at -30 degrees degrees Celsius, or home freezing at -25 degrees Celsius
Fish can be frozen commercially using which method?
Blast freezing
At what temperature does blast freezing take place?
-30 degrees Celsius
At what temperature does home freezing take place?
-25 degrees Celsius
List the effects of freezing on fish.
5
No effect on colour, flavour and texture
Microorganisms are inactivated
Some loss of B-group vitamins and extractives during drip loss when thawed
Freezer burn may occur if packaging is damaged
Oxidative rancidity and enzyme deterioration can occur if fish is stored in the freezer for too long
What are not affected by freezing.
3
Colour
Flavour
Texture
What does freezing do to microorganisms?
Inactivates them
What does freezing inactive?
Microorganisms
How does freezing affect vitamins?
There is some loss of B-group vitamins during drip loss when thawed
What is lost during drip loss when thawed?
2
B-group vitamins
Extractives
When can extractives be lost from frozen fish?
During drip loss when thawed
What may happen during freezing is packaging is damaged?
Freezer burn may occur
What may occur if fish is stored in the freezer for too long?
Oxidative rancidity
Enzyme deterioration
When can oxidative rancidity and enzyme deterioration occur in frozen foods?
When they have been stored for two long
Give three examples of foods which are suitable of being frozen?
Cod
Salmon
Fish products, e.g. fish fingers
Explain the process of canning
2
Fish is placed in sterile cans, sealed and heated to high temperatures.
Fish may be canned in oil, brine, spring water or a sauce, e.g. tomato sauce
Give four substances that fish can be canned in?
Oil
Brine
Spring water
Sauce, e.g. tomato sauce
Give an example of a sauce that fish can be canned in.
Tomato sauce
List the effects of canning.
6
Colour, flavour and texture are changed
Loss of B-group vitamins, particularly thiamine B1
Microorganisms and enzymes are destroyed
Canned fish provides calcium, as the canning process softens fish bones so they can be consumed
Vitamins A and D are provided if fish is canned in oil
Calorie and fat content can increase if fish is canned in oil or a sauce
What are changed during the canning of fish?
3
Colour
Flavour
Texture
What happens to vitamins during the canning of fish?
There is a loss B-group vitamins, particularly thiamine B1
What is the main vitamin lost through canning?
Thiamine B1
What are destroyed by canning?
Microorganisms
Enzymes
What happens to microorganisms and enzymes during the canning process?
They are destroyed
What vitamin content is increased in the canning process?
Vitamins A and D
When are vitamins A and D increased in canned fish?
If the fish is canned in oil
What is increased if fish is canned in oil?
2
Calorie and fat content increase if fish is canned in oil or a sauce
Vitamin A and D content is increased
Give three examples of fish that can be canned.
Tinned mackerel
Tinned tuna
Tinned salmon
Explain the process of smoking fish.
2
Fish is put in brine or rubbed in salt to give flavour and to act as a preservative
It is then smoked by either cold or hot smoking
During the smoking of fish what is done to the fish to flavour it or act as a preservative?
Put in brine or rubbed in salt
After fish has been put in brine or rubbed in salt what is done to it?
It is either cold or hot smoked
Explain the process of cold smoking fish.
3
Involves subjecting fish to smoke from wood chips
The chemicals creosote and formaldehyde in the smoke prevent microorganism growth on fish flesh
The temperature does not go beyond 27 degrees Celsius, so the fish must be cooked before being consumed
What chemicals are present in smoke that preserve fish?
Creosote
Formaldehyde
How does creosote and formaldehyde help preserve fish?
They prevent microorganism growth on fish flesh
What temperatures are reached in cold smoking?
The temperature does not go beyond 27 degrees Celsius
Does cold smoked fish need to be cooked before use?
Yes as temperatures only go to 27 degrees Celsius
Explain the process of hot smoking fish.
2
Follows the same process as cold smoking, but the temperature is gradually increased to approximately 80 degrees Celsius
Fish does not require further cooking to be consumed
What temperatures are reached in hot smoking?
80 degrees Celsius
Does hot smoked fish need to be cooked before being consumed?
No as high enough temperatures are reached
List the effects of smoking fish.
4
Microorganisms and enzymes are destroyed
Colour is changed, e.g. white fish will usually develop a light yellow or brown colour
Flavour is changed to a distinctive, smoky taste
Salt content is increased
What are destroyed during smoking?
Microorganisms and enzymes
What happens to microorganisms and enzymes during smoking?
They are destroyed
What happens to the colour of fish during smoking?
2
Colour is changed
White fish will develop a light yellow or brown colour
What happens to the white colour of white fish during smoking?
It becomes light yellow or brown
What happens to the flavour of fish during smoking?
Flavour is changed to a distinctive, smoky taste
What happens to the salt content of fish during smoking?
The salt content is increased
