by pdst not mine

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

2. Classification of fish
Classified byClassified by
HabitatHabitat
FreshFresh waterwater
e.g. troute.g. trout
SaltSalt waterwater
(a) Demersal e.g.(a) Demersal e.g.
codcod
(b) Pelagic e.g.(b) Pelagic e.g.
herringherring
Farmed e.g.Farmed e.g.
musselsmussels
Classified byClassified by
ShapeShape
RoundRound e.g.e.g.
codcod
FlatFlat e.g. plaicee.g. plaice
Classified byClassified by
Nutritive ValueNutritive Value
OilyOily fish e.g.fish e.g.
herring,herring,
mackerel,mackerel,
trout, salmontrout, salmon
WhiteWhite fish e.g.fish e.g.
cod, haddock,cod, haddock,
plaice, sole,plaice, sole,
whitingwhiting
ShellfishShellfish
(a)(a) CrustaceansCrustaceans
e.g. lobster,e.g. lobster,
prawnprawn
(b)(b) MolluscsMolluscs
e.g. musselse.g. mussels
oystersoysters

3. Structure
of fish

4. Composition of fish
ClassClass ProteinProtein FatFat CarbCarb VitaminsVitamins MineralsMinerals WaterWater
OilyOily 18%18% 15%15% 0%0% ADBADB 2%2%
Iodine, Iron,Iodine, Iron,
andand
Calcium ifCalcium if
tinnedtinned
65%65%
ShellShell 15%15% 2.5%2.5% 0%0% BB 2%2%
Iodine/IronIodine/Iron
79%79%
WhiteWhite 17%17% 0%0% 0%0% BB 1%1%
Iodine/IronIodine/Iron
80%80%

5. Nutritive value
• ProteinProtein: HBV, Actin,: HBV, Actin,
Myosin.Myosin.
• FatFat: white fish- none;: white fish- none;
oily fish- unsaturatedoily fish- unsaturated
+ omega 3 fatty acids;+ omega 3 fatty acids;
shellfish, low fat, highshellfish, low fat, high
cholesterol.cholesterol.
• CarbohydrateCarbohydrate: none,: none,
serve withserve with
carbohydrate richcarbohydrate rich
food.food.

6. Nutritive value
• VitaminsVitamins: B-group all fish;: B-group all fish;
Vitamin C oysters only;Vitamin C oysters only;
Vitamins A&D oily fish +Vitamins A&D oily fish +
stored in liver of cod etc.stored in liver of cod etc.
• MineralsMinerals: Iron in all fish: Iron in all fish
but less than meat;but less than meat;
Iodine in sea fish; calciumIodine in sea fish; calcium
and phosphorus in cannedand phosphorus in canned
fish and fish with ediblefish and fish with edible
bones e.g. sardinesbones e.g. sardines
• WaterWater: 65%-80% depends: 65%-80% depends
on type of fishon type of fish

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

8. Spoilage of fish
Fish is very perishable, must be cooked or processedFish is very perishable, must be cooked or processed
as soon as possible after being caught. Spoilage isas soon as possible after being caught. Spoilage is
caused bycaused by
• Oxidative RancidityOxidative Rancidity: oily fish: oily fish
• Enzymes:Enzymes: cause deterioration even at lowcause deterioration even at low
temperaturetemperature
• BacteriaBacteria: fish struggle when caught, use up all: fish struggle when caught, use up all
glycogen in the cells, therefore no lactic acidglycogen in the cells, therefore no lactic acid
forms to preserve the fish after death. Whenforms to preserve the fish after death. When
bacteria damage fish trimethylamine is formedbacteria damage fish trimethylamine is formed
giving a bad smellgiving a bad smell

9. Buying and storing fish
BuyingBuying
• Fresh and in seasonFresh and in season
• Clean busy shopClean busy shop
• Medium sizeMedium size
• Whole, fillet, cutlets, steaks, tailWhole, fillet, cutlets, steaks, tail
piecepiece
• Whole : Eyes bulge, gills red, skinWhole : Eyes bulge, gills red, skin
moist, flesh firm, sea smellmoist, flesh firm, sea smell
• ShellShell: heavy, molluscs closed,: heavy, molluscs closed,
crustaceans alivecrustaceans alive
• FrozenFrozen: solid, sealed, expiry date: solid, sealed, expiry date
• CannedCanned: no leaks, bulges, dents or: no leaks, bulges, dents or
rust. Check daterust. Check date
• SmokedSmoked: glossy, firm, smoky smell,: glossy, firm, smoky smell,
date, if vacuum packed storedate, if vacuum packed store
unopened in fridge, pack should notunopened in fridge, pack should not
be blown or damagedbe blown or damaged
Storing - freshStoring - fresh
• FridgeFridge
• Unwrap, clean plate withUnwrap, clean plate with
ice , cover looselyice , cover loosely
• Use within 1-2 daysUse within 1-2 days
Storing – frozenStoring – frozen
• Take home in cooler bagTake home in cooler bag
• Put into freezer quicklyPut into freezer quickly
• Use before expiry dateUse before expiry date
• If beginning to thaw useIf beginning to thaw use
right away, do notright away, do not
refreezerefreeze

10. Preserving and
processing fish
FreezingFreezing
• Blast frozen @ -30Blast frozen @ -30ºC , cold tempºC , cold temp
stops microbes rotting the fish,stops microbes rotting the fish,
retain colour, texture, tasteretain colour, texture, taste
nutrition, oily fish keeps for 3nutrition, oily fish keeps for 3
months only due to rancidity. Somemonths only due to rancidity. Some
fish is coated or frozen in sauce.fish is coated or frozen in sauce.
CanningCanning
• Salmon, sardines, mackerel, tuna,Salmon, sardines, mackerel, tuna,
anchovies. Canned in brine, oil oranchovies. Canned in brine, oil or
sauce. The heat used in canningsauce. The heat used in canning
destroys all microbes and enzymesdestroys all microbes and enzymes
and sealing prevents re-entry. Onlyand sealing prevents re-entry. Only
canned fish have calcium. Vitamin Bcanned fish have calcium. Vitamin B
destroyed by canning.destroyed by canning.
SmokingSmoking
• Salmon, trout, kippers, mackerel,Salmon, trout, kippers, mackerel,
crab. The chemicals creosote andcrab. The chemicals creosote and
formaldehyde in the smoke preventformaldehyde in the smoke prevent
microbial growth. Fish is salted, thenmicrobial growth. Fish is salted, then
cold smoked @ 27 ºC (raw) or hotcold smoked @ 27 ºC (raw) or hot
smoked @ 80 ºC need no moresmoked @ 80 ºC need no more
cooking. Gives flavour, colour sheencooking. Gives flavour, colour sheen

11. Cooking fish Effects of cookingEffects of cooking
• Microbes & parasites destroyed.Microbes & parasites destroyed.
• Protein coagulates and shrinksProtein coagulates and shrinks
• Collagen changes to gelatine fishCollagen changes to gelatine fish
flakes fall apartflakes fall apart
• Flesh becomes opaqueFlesh becomes opaque
• Loss of Vitamin BLoss of Vitamin B
• Minerals and vitamins dissolveMinerals and vitamins dissolve
into cooking liquidinto cooking liquid
• Overcooked…dry and toughOvercooked…dry and tough
RulesRules
• FreshFresh
• Wash and dry well before cookingWash and dry well before cooking
• Cooks quicklyCooks quickly
• Gentle cooking…breaks apartGentle cooking…breaks apart

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