FISH & SHELLFISH

• 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

M olluskssoft s truc ture

hardshelle .g oys ters

C rus taceanscrus tlike shell

seg,em ted bodye.g c rayfish,

Invertebrates(shellfish)

shells

W hite fish(lean)

E .gs : snappercod, so le

O ily fish(fa t)

E .gs : S alm onM ackere l

V ertebratesfins

scales

F ish and shellfish

Saltwater fish - more distinctive flavors than freshwater fishOily fish - more flvaour than the white lean varieties

Composition and Nutritive value

Fish protein has a high biological valueas that of land animals; 18-20% of protein.

white fish 10% with energy value 50-80 Kcal/100gRoe 30% protein.Mollusks 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.

Protein

Fat

Lean fish - less than 1% of fatOily fish - 8-15% fat, hence higher energy value 80-160 kcal/100gShellfish - little fat & energy value 50kcal, high cholesterol esp

lobsters and crabs, cuttlefish and moderately high in prawns

VitaminsFish -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

MineralFish -good source of phosphorus

-good source of calcium when eaten with bonesShell Fish - calcium, iron and iodine

- e.g. cockles are esp. rich in iron & iodine

WaterFish - white fish 80%

- Oily fish 67%

Shellfish – high water content

Oysters are the richest food source for zinc

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)

CookingThaw fish over night in the refrigeratorFish are less tasty than meat. Good cooks uses a variety of sauces, garnishes, herbs and spices to make fish interestingand 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-fryingSome shrinkage occurs as protein coagulateAs fish shrinks, water evaporates from surface & leaves behind deposit of

flavoring matter & mineral salts, hence makes surface of fish tastyThis 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