fish Flashcards
what is the classification of fish
-shape: flat, round fish
-habitat: saltwater, freshwater
-nutritional value: white, oily fish
what is the nutritional value of fish
proteins: an excellent source of HBV protein
-main proteins present are myosin and actin in the myomeres and collagen in the connective tissue
fat: oily fish are a source of polyunsaturated fat, especially omega-3 fatty acids
-no fat is present in white fish as it is removed during filleting
carbohydrates: lacks carbohydrates as any glycogen is converted to lactic acid during the struggle when fish are caught. usually fish is served with a carbohydrate-rich food
vitamins: a source of B-group vitamins
-oily fish and white fish livers contain vitamins A and D
-some shellfish are a source of vitamins A and C
minerals: contain small amounts of iodine, zinc, potassium, phosphorus and fluorine
-shellfish especially mussels and oysters are good sources of iron
-canned fish are a source of calcium as the bones are eaten
water: varies depending on the fish type
-the higher the water content the less fat present
what is the dietic value of fish
-fish is an important source of easily digestible HBV protein, which assists with growth and repair, this makes it a valuable food in the diets of children, teenagers and pregnant women
-as white fish contains no fat, it is low in kilocalories. this makes it an ideal food for individuals following calorie-controlled diets
-fish is a versatile food suited to many different cooking methods and flavour combinations
-oily fish contains polyunsaturated fat, especially omega-3 fatty acids so it is beneficial in low-cholesterol diets as it helps to increase high-density lipoproteins that help lower cholesterol levels
-fish lacks carbohydrates so it should be combined with carbohydrate-rich foods to balance the diet
what are the guidelines for buying fish
-ensure whole fish have bright and bulging eyes. gills should be bright red
-check the use-by date on pre-packaged fish
-ensure cuts have firm, transparent flesh no discolouration such as bruising should be evident
-ensure fish has firm, elastic flesh. the skin should be shiny, moist, unbroken and slime-free, as slime is an indication of bacterial growth
-buy fish from a retailer with a clean and hygienic fish counter. the retailer should have a strict food hygiene and safety policy to ensure any fish being sold is safe and fit for consumption
what are the guidelines for storing fish
-store fish in a fridge at 4C as room temperature speeds up bacterial growth, increasing the rate of spoilage
-store strong-smelling fish away from foods likely to absorb the flavour such as milk and butter
-if freezing fresh fish, freeze at -25C on the day of purchase
-if purchased loose, remove from the wrapper rinse under cold water and place on a plate or container that will collect any juices
what are the guidelines for filleting a whole fish
-scrape off the scales with the back of a knife
-cut off the head and fins
-cut the underside of the fish and remove the intestine
-wash the cavity by running it under the tap
what are the guidelines for cooking fish
-choose an appropriate cooking method suited to the type of fish
-avoid overcooking fish as it becomes tough, rubbery and difficult to digest
what are the effects of cooking on fish
-protein coagulates at 40-50C causing fish to shrink
-colour changes from translucent to opaque
-bacteria are destroyed
-fish can become tough, rubbery and difficult do digest if overcooked
-flavour develops as extractives are released out of the fish fibres
explain the process of freezing fish
can be frozen by commercial blast freezing at -30C or home freezing at -25C
what are the effects of freezing fish
-no effects on colour, flavour and texture
-freezer burn may occur if packaging is damaged
-microorganisms are inactivated
-oxidative rancidity and enzyme deterioration can occur if fish is stored in the freezer for too long
what are the fish types used for freezing
-cod
-salmon
what is the process of canning fish
fish is placed in sterile cans, sealed and heated to high temperatures. fish may be canned in oil, brine, spring water or a sauce
what are the effects of canning fish
-colour, flavour and texture are changed
-loss of B-group vitamins particularly B1
-microorganism s and enzymes are destroyed
-calorie and fat content increase if fish is canned in oil or sauce
what types of fish are used in canning
-tinned salmon
-tinned tuna
what are examples of processed fish products
-fish cakes
-fish fingers
