Chapter 7Chapter 7

Understanding Fish and ShellfishCopyright © 2011 by John Wiley & Sons, Inc. All Rights Reserved

Fish products are divided into two categories:• Fin fish, or fish with fins and internal skeletons.

• Shellfish, or fish with external shells but no internal bone structure.

2

Understanding Fish and Shellfish

The edible flesh of fish consists of: • Water

• Proteins

• Fats

• Small amounts of minerals, vitamins, and other substances

3

Composition and Structure

Fish has very little connective tissue.• This means that:

• Fish cooks very quickly.

• Fish is naturally tender.

• Moist-heat cooking methods are used not to create tenderness but to preserve moistness.

• Cooked fish must be handled very carefully or it will fall apart.

4

Composition and Structure

The fat content of fish ranges from 0.5% to 20%.• Lean fish are those that are low in fat.

• Fat fish are those that are high in fat.

5

Special Problems in Cooking Fish

Cooking Fat Fish and Lean Fish

Whole or round: completely intact, as caught.

6

Cutting Fish

Market Forms

Drawn: viscera removed.

Dressed: viscera, scales, head, tail and fins removed.

7

Cutting Fish

Market Forms

Steaks: cross-section slices, each containing a section of backbone.

Fillets: boneless sides of fish, with skin on or off.

8

Cutting Fish

Market Forms

Sticks or tranches: cross-section slices of fillets.

Butterflied Fillets: both sides of a fish still joined.

9

Cutting Fish

Market Forms

Cut off the tail and fins. Scissors are easiest to use.

Scale the Fish.

10

Cutting Fish

Dressing a Fish

Slit the belly and pull out the viscera. Rinse the cavity.

Remove the head. Cut through the flesh just behind gills. Cut or break the backbone at the cut and pull off the head.

11

Cutting Fish

Dressing a Fish

The fish is dressed.

Use a thin-bladed, flexible knife. Cut off the head just behind the gills (this step is optional).

12

Cutting Fish

Filleting a Flatfish

Make a cut from head to tail, just to one side of the center line down to the backbone.

Turn the knife so it is almost parallel to the table. Making long, smooth cuts, cut horizontally against the backbone toward the outer edge of the fish. Gently separate the fillet from the bone.

13

Cutting Fish

Filleting a Flatfish

Remove the fillet completely.

Cut into the top of the fish along one side of the tail; detach the backbone from head to tail.

14

Cutting Fish

Filleting a Round Fish

Cut under the flesh toward the tail and detach the cut piece.

Cut along the curved rib bones and finish detaching the fillet at the head. Turn the fish over and repeat to remove the second fillet.

15

Cutting Fish

Filleting a Round Fish

Overall appearance• Good appearance

Clear slime• Moist and pliable fins

Odor • Fresh and mild with no off-odors

Eyes • Clear, shiny and bulging

16

Handling and Storage

Checklist for Fish Freshness

Gills

• Red or pink

Texture of flesh

• Firm; elastic

Scales

• Shiny; tight on skin

Belly cavity

• No belly burn; natural-colored flesh, pink or red along backbone

17

Handling and Storage

Checklist for Fish Freshness

Objectives

1. To maintain temperature of 29° to 32°F (–2° to 0°C).

2. To keep the fish moist.

3. To prevent fish odors and flavors from transferring to other foods.

4. To protect the delicate flesh from being bruised or crushed.

18

Handling and Storage

Storing Fresh Fish

Methods• On crushed ice (preferred method):

• Use drip pans to allow for drainage of melted ice.

• Change ice daily.

• In refrigerated box at 29° to 32°F (–2° to 0°C):

• Use if crushed ice storage is not available or practical.

• Wrap all fish or leave in original moisture proof wrap.

19

Handling and Storage

Storing Fresh Fish

Storage Time• Fresh fish may be stored for 1 or 2 days. If it must be

kept longer, you may:

1. Wrap and freeze it immediately.

2. Cook and then refrigerate it for later use in recipes calling for cooked fish.

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Handling and Storage

Storing Fresh Fish

Federal Inspection

In the United States, voluntary inspections are conducted by:

1. The National Oceanic and Atmospheric Administration (NOAA).

2. The Department of Commerce.

• Promotes the safety of processed fish and shellfish.

21

Handling and Storage

Frozen, Canned, and Other Processed Fish

Federal Inspection (cont’d)

3. Processors who wish to take part in the programs must pay for the service.

4. They may then use official seals or marks on their product packaging and in advertising.

• PUFI seal (Processed Under Federal Inspection)

• U.S. Grade A shield

22

Handling and Storage

Frozen, Canned, and Other Processed Fish

Thawing and Handling• Frozen raw fish

• Thaw in refrigerator.

• Small pieces can be cooked from a frozen state.

• Fillets, or other portions to be breaded or prepared in some other way before cooking, may be partially thawed.

• Handle thawed fish as you would fresh fish.

• Do not refreeze.

23

Handling and Storage

Frozen, Canned and Other Processed Fish

There are two classifications of shellfish:

1. Mollusks: Soft sea animals that fall into three main categories:

• Bivalves, which have a pair of hinged shells (such as clams and oysters).

• Univalves, which have a single shell (such as abalone and conch).

• Cephalopods (such as octopus, squid and cuttlefish).

2. Crustaceans: Animals with segmented shells and jointed legs.

24

Shellfish

Classification

25

Shellfish

Mollusks

Oysters

Clams

Mussels

Scallops

Squid• Usually referred to on

menus by their Italian name, calamari.

Octopus• The name means “eight

feet.”

26

Shellfish

Cephalapods

27

Shellfish

Crustaceans

Lobster

Crab

Shrimp