FISH & SHELLFISH
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Classifications (types & structures)
Nutritive value
Selection and storage
Preparation
Cooking
Textbook Pg 113-117
Structures of Fishes
• Less connective tissues than meat & no
elastin
• Not tough as muscle fibres are short & held
together by connective tissues
• Hence, fish is more digestible than meat
Classifications
Fish and shellfish
Invertebrates
(shellfish)
shells
Mollusks
soft structure
hardshell
e.g oysters
Crustaceans
crustlike shell
seg,emted body
e.g crayfish,
Vertebrates
fins
scales
White fish
(lean)
E.gs: snapper
cod, sole
Oily fish
(fat)
E.gs: Salmon
Mackerel
Saltwater fish - more distinctive flavors than freshwater fish
Oily fish - more flvaour than the white lean varieties
Composition and Nutritive value
Protein
Fish protein has a high biological value
as that of land animals; 18-20% of protein.
white fish
Roe
Mollusks
 10% with energy value 50-80 Kcal/100g
 30% protein.
 15%.
Fish meal & fish flour - excellent nutrient content,
prepared from small whole fish for animal feeds while
some are added into human foods such as cereals, bread
and noodles.
Fat
Lean fish - less than 1% of fat
Oily fish - 8-15% fat, hence higher energy value 80-160 kcal/100g
Shellfish - little fat & energy value 50kcal, high cholesterol esp
lobsters and crabs, cuttlefish and moderately high in
prawns
Vitamins
Fish -Vit A and D in oily fish. Why?
-some vit. B groups e.g. thiamine, riboflavin, nicotinic acid
(present in small amounts)
Shellfish –
Vit. A content is good in some shellfish. B
groups vitamins are present in all shellfish
Mineral
Fish -good source of phosphorus
-good source of calcium when eaten with
bones
Shell Fish - calcium, iron and iodine
- e.g. cockles are esp. rich in iron &
iodine
Oysters are the richest food source for zinc
Water
Fish - white fish  80%
- Oily fish  67%
Shellfish – high water content
Fish and seafoods
• white fish– < 1% fat
– eg cod, halibut, pomfret (ikan bawal), red snapper (ikan
merah), threadfin (ikan kurau)
• Intermediate– 2-10% fat
– eg trout
• Fat fish– 10-25% fat
– eg herrings, salmon, sardines, mackerel, tuna
– vit. A & D disperse through out fat and liver
Selection and storage
Fresh finfish- firm fins & body, tight scales, gills are red &
eyes are bright and not sunken. Pressure on
the body does not leave an indentation, except
frozen/ thawed. Body not slimy and does not
have an unpleasant stale smell.
Storage- Fresh fish should be kept in freezer
Mollusks should be refrigerated in containers
covered loosely with a clean damp cloth.
Preparing Fish for Cooking
• Cook fish while it is fresh
• Fish should be cleaned, washed & put in polythene bag
before placed in freezer (should be eaten within a few days)
• Once thawed, should not be frozen again
Preparing Shellfish for Cooking
• Cook shellfish while it is fresh
• Scrub clean any hard outer shell or remove shell
• Scrub clean shellfish such as cockles & mussels & soak
them in water (add little salt)
Cooking
Thaw fish over night in the refrigerator
Fish are less tasty than meat. Good cooks uses a variety of
sauces, garnishes, herbs and spices to make fish interesting
and appetizing.
Cooking methods used depend on whether fish is oily or white.
Oily fish grilled, baked or pan-fried so that natural flavour is
conserved
White fish  deep fried so that it will tastes better
Shellfish- moist-heat generally satisfactory.
Lobsters- parboiled in salted water, over done
toughens the meat
Cooking Fish
• Retention of forms- if cooked in water, tie fish in cheesecloth
• Small fish- frying, curry fish- should use bigger fish & less bones
• Moist heat  steaming, boiling
 soluble proteins & extractives are lost to the liquid, fish
tends to be tasteless
 therefore usually eaten with a sauce, which may be
made from the liquid the fish is cooked in to prevent
wastage of soluble nutrients
• Dry heat  grilling, baking, pan-frying
Some shrinkage occurs as protein coagulate
As fish shrinks, water evaporates from surface & leaves
behind deposit of flavoring matter & mineral salts, hence
makes surface of fish tasty
This method conserves flavor & nutritive value
Cooking Shellfish
• Little time needed
• Preferably, they should be cooked just before eating it
• Cooking method: fry them quickly, steaming or quick
boiling
• Do not overcook  makes them tough & less digestible
• Must be cooked properly  common cause of food
poisoning