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Fish - Coggle Diagram
Fish
Nutritional Value
Proteins:Excellent source of HBV (High biological value) protein. Main proteins present are myosin and actin in the myomeres and collagen in the connective tissue
Fat:Oily fish is a source of polyunsaturated fat especially omega 3 fatty acids eicosapentaenioc acid and docosahexaenoic acid. No fat is present in white fish, as white fish store fat in their livers, which are removed during filleting
Carbohydrates:Lacks carbohydrates as any glycogen is converted to lactic acid during the struggle when fish are caught.
Vitamins:Source of B group vitamins, especially B6 (For a healthy nervous system) and B12 (Forms red blood cells).
Oily fish and white fish livers contain vitamins A and D
Minerals:Contains small amounts of iodine (Prevents Grote), Zinc, Potassium, Phosphorus (works with vitamin D and Calcium for healthy bones and teeth) and Fluorine. Shellfish especially mussels and oysters are good sources of iron. Canned fish contains Calcium as bones are eaten
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Structure of Fish
Myomeres: Are short, thick fibres arranged in broad vertical bands. They contain the proteins actin and myosin, Minerals, vitamins, water and extractives.
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Fat:In only fish is invisible due to it being dispersed between the myomeres and the connective tissue. The flesh of white fish contains no fat since it is stored in their livers. These livers are often pressed to form nutritional supplements e.g cod liver oil.
Outer layer:is a waterproof, scaly skin that covers the flesh of white and oily fish. A shell encloses the flesh of shellfish
Dietetic Value of fish:
Important source of HBV protein which assists with growth and repair in cells making it a valuable food for children, teenagers and pregnant women (Positive)
Fish is a very versatile food suited to many different cooking methods and flavor combinations (Positive)
Contains no carbohydrates meaning it should be complimented with carbohydrate rich foods such as pasta (Negative)
Pregnant women should reduce the amount of tuna consumed since it contains a small amount of mercury which could cause birth defects (Negative)
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Spoilage of Fish
Oxidative rancidity:Oils in oily fish react with oxygen in the air. Oxygen combines with the carbon in double bonds along the unsaturated fatty acid chain, causing the fish to become rancid.
Enzymes:Naturally present enzymes in fish cause its flesh to deteriorate, even at low temperatures. This can be slowed by placing fish on ice or in the fridge
Bacteria:When fish are caught they struggle frantically, using up the glycogen in their muscles and liver. This results in little glycogen being left to convert to lactic acid to preserve the fish which in turn causes rapid deterioration by bacterial action.
Processed fish products
Fish cakes:Made from minced fish, potato, herbs and seasoning. They're shaped into rounds, coated in breadcrumbs or batter, briefly fried and then frozen. Contains 35%-45% fish
Fish Fingers:Made from blocks of frozen, filleted white fish that are cut into fingers, dipped into a batter or breadcrumbs and refrozen. Contain 50%-75%
Fish extractives:e.g fish stock cubes. Made from fish juice extractives that are dried and mixed with corn flour, salt, yeast extract and flavor enhancers
Guidelines
For Buying Fish
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Fish should always have a smell of the sea. An unpleasant smell can indicate bacterial growth. Smoked fish should always have a fresh. smokey odour.
Buy fish near the end of a shopping trip tp minimize the amount of time of spends at room temperature
For storing fish
Store fish at 4 degrees Celsius as room temperature speeds up bacterial growth, increasing the rate of spoilage
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If freezing fresh fish, freeze at -25 degrees Celsius.
Preparing fish + Cooking
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Cooking
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Effects
Protein coagulates at 40-50 degrees Celsius, causing fish to shrink
Some B-Group vitamins are lost, as they are not heat stable
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