Fish Flashcards
How can We classify fish
By shape
By habitats
By nutritional value
Types of shape fish classification
Flat fish for example plaice or sole
round fish for example tuna cod salmon
Types of fish by habitat
Freshwater fish e.g. salmon trout
Sea water fish, demersal fish eg cod plaice and pelagic fish eg mackerel, tuna
Farmed fish e.g. salmon mussels
Where do you demersal fish live
Near the seabed
Where do pelagic fish live
Near the surface of the sea
Fish classified by nutritional value
White fish e.g. cod plaice Whiting monkfish
Oily fish e.g. mackerel tuna salmon
Shellfish, molluscs eg oysters and mussels, crustaceans eg lobster
Difference between molluscs and crustaceans
Molluscs have a hard shell and no loves
Crustaceans have a heard shell and claws and legs
What are the myomeres in fish
Vertical Fibres is containing proteins minerals water and vitamins
What is the function of the connective tissue in the fish
Hold the myomeres in place
Why don’t whitefish have fat
Because they store their fat in the liver
That’s why you can make fish liver oil tablets
Percentages for white fish
Protein..17. 5% Fat.. 0. 5% Carbohydrates..0% Vitamins.. b group Minerals..Zinc, potassium, phosphorus, fluorine, iodine Water… 80.5%
Percentages in oily fish
Protein… 18% Fat… 15 to 18% Carbohydrates…0% Vitamins… A , B group, d Minerals… zinc, potassium ,phosphorus ,fluoride and Iodine Water… 65%
Percentages in shellfish
Protein..16% Fat… 3% Carbohydrates… 0% Vitamins..A, B group, C Minerals.. iron, sink, potassium, phosphorus, fluoride, iodine Water…78%
Dietetic value Of fish
Easily digestible HPV protein growth and repair
Low in kilo calories ideal for people losing weight
Polyunsaturated fat and omega 3 fatty acid‘s help lower cholesterol
Available in main types
Versatile
Fish can be inexpensive
Lax carbohydrates
Guidelines for buying fish
Clean hygienic retailer Check use by date on prepackaged fish Skin should be firm shiny and moist, no slime.slime indicates bacterial growth Scales should not come off easily Eye should be bright and bulging Gills should be read No bruising Shellfish should be closed and alive Shouldn’t smell Buy near the end of the shopping trip so it’s only out of the fridge for a minimum amount of time
Guidelines for storing fish
In fridge to avoid bacterial growth
Away from foods that absorbs flavour
Don’t store are too long
Three main causes of fish spoilage
Oxidative rancidity
Enzymes
Bacteria
What is oxidative rancidity
When fish reacts with oxygen in the air
It’s combines with carbon is in the double bond along to unsaturated fatty acid chains causing the fish to become rancid
How do enzymes cause spoilage
Naturally present enzymes in the fish will denature of the fish flesh. this is slowed down by putting the fish in the fridge
How does bacteria spoil fish
When fish areI caught they struggle frantically
By doing this they use up glycogen in their muscles
glycogen cannot convert to lactic acid to preserve the fish and bacteria can grow
Effects of cooking on fish
Protein coagulates
Changes colour from translucent to Opaque
B group vitamins are lost due to the high heat
Pathogenic bacteria are destroyed
Flavour develops
Collagen converts to gelatine, fibres loosen and fall part
Can become rubbery, tough and difficult to digest when overcooked
What is the only fish that can be slow cooked
Monk fish
Three types of fish processing
Freezing
Canning
Smoking
Effects of freezing on fish
No change in colour, texture or flavour microorganisms are inactivated Loss of B group vitamins Freezer burn may occur Enzyme denaturation may occur if stored for too long
Effects of Canning on fish
The colour, flavour and texture change
Loss of b group vitamins
Microorganisms and enzymes are destroyed
Calcium is provided as bones soften and are eating
A and D vitamins provided when canned in oil
Calorie and fat intake can increase due to sauce
What can fish be canned in
Oil
Brine
Tomato sauce
Spring water
What is smoking fish
Fish is put in brine or rubbed in salt for flavour and to preserve then smoked
Two types of smoking
Hot - high temperature, fish is fully cooked
Low - fish not fully cooked
Effects of smoking on fish
Microorganism and enzymes destroyed
Colour change
Flavour change - smokey flavour
Salt increased
Fish products
Fish cakes
Fish fingers
Fish extracts eg stock cube
