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

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 Nutritive Value Oily fish e.g. herring, mackerel, trout, salmon White fish e.g. cod, haddock, plaice, sole, whiting Shellfish Crustaceans e.g. lobster, prawn Molluscs e.g. mussels oysters

Structure of fish

Composition of fish Class Protein Fat Carb Vitamins Minerals Water Oily 18% 15% 0% ADB 2% Iodine, Iron, and Calcium if tinned 65% Shell 2.5% B Iodine/Iron 79% White 17% 1% 80%

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

Nutritive value 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. sardines Water: 65%-80% depends on type of fish

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. Dietetic value

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 fish Enzymes: 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 smell

Buying and storing fish Fresh and in season Clean busy shop Medium size Whole, fillet, cutlets, steaks, tail piece Whole : Eyes bulge, gills red, skin moist, flesh firm, sea smell Shell: heavy, molluscs closed, crustaceans alive Frozen: solid, sealed, expiry date Canned: 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 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

Preserving and processing fish Freezing Blast frozen @ -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. Smoking Salmon, trout, kippers, mackerel, crab. The chemicals creosote and formaldehyde in the smoke prevent microbial growth. Fish is salted, then cold smoked @ 27 ºC (raw) or hot smoked @ 80 ºC need no more cooking. Gives flavour, colour sheen increases sodium. Preserving and processing fish

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

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