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Fish Even a fish wouldn’t get into trouble if it kept its mouth shut © PDST Home Economics.

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Presentation on theme: "Fish Even a fish wouldn’t get into trouble if it kept its mouth shut © PDST Home Economics."— Presentation transcript:

1 Fish Even a fish wouldn’t get into trouble if it kept its mouth shut © PDST Home Economics

2 Classification of fish Classified by Habitat Fresh water e.g. trout Salt water (a) Demersal e.g. cod (b) Pelagic e.g. herring Farmed e.g. mussels Classified by Shape Round e.g. cod Flat e.g. plaice Classified by Nutritive Value Oily fish e.g. herring, mackerel, trout, salmon White fish e.g. cod, haddock, plaice, sole, whiting Shellfish (a)Crustaceans e.g. lobster, prawn (b)Molluscs e.g. mussels oysters

3 Structure of fish

4 Composition of fish ClassProteinFatCarbVitaminsMineralsWater Oily18%15%0%ADB2% Iodine, Iron, and Calcium if tinned 65% Shell15%2.5%0%B2%Iodine/Iron79% White17%0%0%B1%Iodine/Iron80%

5 Nutritive value Protein: HBV, Actin, Myosin.Protein: HBV, Actin, Myosin. Fat: white fish- none; oily fish- unsaturated + omega 3 fatty acids; shellfish, low fat, high cholesterol.Fat: white fish- none; oily fish- unsaturated + omega 3 fatty acids; shellfish, low fat, high cholesterol. Carbohydrate: none, serve with carbohydrate rich food.Carbohydrate: none, serve with carbohydrate rich food.

6 Nutritive value Vitamins: B-group all fish; Vitamin C oysters only; Vitamins A&D oily fish + stored in liver of cod etc.Vitamins: B-group all fish; Vitamin C oysters only; Vitamins A&D oily fish + stored in liver of cod etc. Minerals: Iron in all fish but less than meat; Iodine in sea fish; calcium and phosphorus in canned fish and fish with edible bones e.g. sardinesMinerals: Iron in all fish but less than meat; Iodine in sea fish; calcium and phosphorus in canned fish and fish with edible bones e.g. sardines Water: 65%-80% depends on type of fishWater: 65%-80% depends on type of fish

7 Dietetic value Versatile, tasty, quick to cook. HBV protein – healthy meat substitute especially teenagers, child, pregnant women. Unsaturated fat and omega 3 means its good for those with heart disease and high cholesterol. White fish low energy food good for low calorie diets. White fish easily digested therefore good for invalids and elderly. Iodine in sea fish prevents goitre. Nutritional convenience food when canned or frozen in breadcrumbs, batter or sauce. Lacks carbohydrates. and Vitamin C. Serve with starchy food and salad/vegetables.

8 Spoilage of fish Fish is very perishable, must be cooked or processed as soon as possible after being caught. Spoilage is caused by Oxidative Rancidity: oily fishOxidative Rancidity: oily fish Enzymes: cause deterioration even at low temperatureEnzymes: cause deterioration even at low temperature Bacteria: fish struggle when caught, use up all glycogen in the cells, therefore no lactic acid forms to preserve the fish after death. When bacteria damage fish trimethylamine is formed giving a bad smellBacteria: fish struggle when caught, use up all glycogen in the cells, therefore no lactic acid forms to preserve the fish after death. When bacteria damage fish trimethylamine is formed giving a bad smell

9 Buying and storing fish Buying Fresh and in seasonFresh and in season Clean busy shopClean busy shop Medium sizeMedium size Whole, fillet, cutlets, steaks, tail pieceWhole, fillet, cutlets, steaks, tail piece Whole : Eyes bulge, gills red, skin moist, flesh firm, sea smellWhole : Eyes bulge, gills red, skin moist, flesh firm, sea smell Shell: heavy, molluscs closed, crustaceans aliveShell: heavy, molluscs closed, crustaceans alive Frozen: solid, sealed, expiry dateFrozen: solid, sealed, expiry date Canned: no leaks, bulges, dents or rust. Check dateCanned: no leaks, bulges, dents or rust. Check date Smoked: glossy, firm, smoky smell, date, if vacuum packed store unopened in fridge, pack should not be blown or damagedSmoked: glossy, firm, smoky smell, date, if vacuum packed store unopened in fridge, pack should not be blown or damaged Storing - fresh Fridge Unwrap, clean plate with ice, cover loosely Use within 1-2 days Storing – frozen Take home in cooler bag Put into freezer quickly Use before expiry date If beginning to thaw use right away, do not refreeze

10 Preserving and processing fishFreezing Blast -30ºC, cold temp stops microbes rotting the fish, retain colour, texture, taste nutrition, oily fish keeps for 3 months only due to rancidity. Some fish is coated or frozen in sauce.Blast -30ºC, cold temp stops microbes rotting the fish, retain colour, texture, taste nutrition, oily fish keeps for 3 months only due to rancidity. Some fish is coated or frozen in sauce.Canning Salmon, sardines, mackerel, tuna, anchovies. Canned in brine, oil or sauce. The heat used in canning destroys all microbes and enzymes and sealing prevents re-entry. Only canned fish have calcium. Vitamin B destroyed by canning.Salmon, sardines, mackerel, tuna, anchovies. Canned in brine, oil or sauce. The heat used in canning destroys all microbes and enzymes and sealing prevents re-entry. Only canned fish have calcium. Vitamin B destroyed by canning.Smoking Salmon, trout, kippers, mackerel, crab. The chemicals creosote and formaldehyde in the smoke prevent microbial growth. Fish is salted, then cold 27 ºC (raw) or hot 80 ºC need no more cooking. Gives flavour, colour sheen increases sodium.Salmon, trout, kippers, mackerel, crab. The chemicals creosote and formaldehyde in the smoke prevent microbial growth. Fish is salted, then cold 27 ºC (raw) or hot 80 ºC need no more cooking. Gives flavour, colour sheen increases sodium.

11 Cooking fish Effects of cooking Microbes & parasites destroyed. Protein coagulates and shrinks Collagen changes to gelatine fish flakes fall apart Flesh becomes opaque Loss of Vitamin B Minerals and vitamins dissolve into cooking liquid Overcooked…dry and tough Rules Fresh Wash and dry well before cooking Cooks quickly Gentle cooking…breaks apart

12 Cooking fish continued Methods: Frying, grilling, poaching, steaming, baking, stewing, barbecuing, microwave Coatings: Flour, egg + breadcrumbs, oatmeal, batter Sauces: Parsley, hollandaise, tartare, tomato, cheese, Marie Rose Garnishes: Lemon, parsley, cucumber, tomato lilies, peas


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