Lesson IX Fish PDF

Lesson IX **FISH** **The Nature of Fish** Fish is scientifically known as Istiophorus Orientalis. This group of flesh foods may be classified into two categories: fish (vertebrates) and shellfish (invertebrates). Fish is covered with scales while the shellfish is encased in some type of shell. Sh...

Lesson IX **FISH** **The Nature of Fish** Fish is scientifically known as Istiophorus Orientalis. This group of flesh foods may be classified into two categories: fish (vertebrates) and shellfish (invertebrates). Fish is covered with scales while the shellfish is encased in some type of shell. Shellfish is of two groups , the mollusks and crustaceans. The mollusks are soft in structure and are either partially or wholly enclosed in a hard shell that is largely of mineral composition, examples of mollusks are oysters, clams, abalone, scallops, and mussels. The crustaceans are covered with crust-like shells and have segmented bodies. common examples are lobster, crab, shrimp, and crayfish. The kinds of scaly fish available for food vary widely in different localities. They include both saltwater and fresh water varieties and differ in flavor and quality depending partly on the water in which they are grown. Most fish are caught in the open seas and their availability is not dependent on man's productive efforts, unlike agricultural or farming crops, but rather on his ability to detect and catch large schools of fishes. However in the Philippines, we have learned to culture some marine fish and bangus. this is the foremost example. the act of culture g fish in land water called ***aquaculture,*** while that of culturing in salt water bodies such as coves and shores is ***mariculture.*** Mariculture , presently applied to tahong and oysters, is relatively in its infancy in the Philippines. Fish has always been and important item in the Philippine diet and one of the cheapest sources of protein; and thus can take the place of chicken, pork, carabeef, or beef. Like these meats, the protein of fish contains all the essential amino acid; hence it has a high biological value. **Deteriorative Changes After Death** Most fish caught from the sea die even while still in the net in the water. Those caught or harvested from inland waters also die shortly after they are taken from water. An exception are those of fish with accessory breathing organs like hito and dalag which stay alive after catch. The deteriorative changes after death of fish are important to its acceptability as food. Immediately after death, the fleshy portion or muscle of fish is soft, gel-like and sticky. The ***rigor mortis*** sets in and is characterized by rigidity of the muscle. When rigor has passed, spoilage starts. This is caused mainly by fish enzymes and bacteria. The bacteria come from the slime of the fish skin as well as from the gills and intestinal tract. The flesh of a healthy fish is actually sterile. The enzymes which are found mainly in the intestinal organs of the fish start digesting the neighboring flesh. A substance which is found in living fish flesh called ***trime-thylamine oxide*** is converted to ***trimethylamine***, which imparts the characteristic odor of stale fish. Oxidative deterioration or rancidity of fish fat follows. **Nutritive Value of Fish** **Protien-** Fish is one of the most valuable sources of high grade protein. Most fish contain 18-20% protein with most of the essential amino acids in the right proportion. ***Apahap, lapu-lapu, labahita, tulingan, talakitok, bia and kanduli*** have generally high protein content. Protein is needed in repair and growth of body tissues. **Fat-** the fat content of fish varies. Most fish varieties are low in fat (less than one percent) thus being moderately low in calories. Fat is not always uniformly distributed throughout the flesh of a fatty fish but it is found on the belly, head and liver- where the bulk of it is stored. **Vitamins-** Fish liver oils are topically rich sources of vitamin A. Often parts of a fish not normally eaten like the liver an gut, contain much greater quantities of oil-soluble vitamins than the flesh. Fish roe, when present , is also good source of vitamins. An average serving of fish meat supplies 1/20 to 1/5 of the daily allowance for B, 1/25 to 1/5 of B2, and 1/10 to ½ of niacin. These water-soluble concentrates contain an appreciable amount of Vitamin B2- a growth promoting compound. **Minerals-**the edible portions of the fish are satisfactory sources of magnesium, phosphorous, iron, copper and iodine. Shellfish is rich in minerals such as calcium, which is good for our bones. Inclusion of fish in the daily diet provides an abundant mineral intake. **Carbohydrates-** All shellfish has some carbohydrates in the form of glycogen. Its sweet taste is due to the glucose formed by enzyme action from glycogen. **Distinguishing Characteristics of Fresh and Stale Fish** **Criteria** **Fresh** **Stale** --------------- -------------------------------------------------- -------------------------------------------------------- Eyes Bright, full, bulging Dull, wrinkled, sunken Gills Bright red, covered with clear slime, odor fresh Dull brown or gray, slime cloudy, odor offensive Odor Fresh seaweedy odor State, sour, putrid body firm soft color Bright, shiny faded Flesh Firm, elastic, finger impression does not remain Soft and flabby finger impression remains Slime clear Opaque Belly walls intact Often raptured, viscera protruding Muscle tissue White, light Pinkish, tainted with blood especially around backbone vent Pink, not protruding Brown protruding Scales Complete, adhere tightly, sink Loosely attached Test Sinks in basin of water Floats in basin of water Taste sweet Biting, itchy **MARKET FORMS OF FISH** 1\. **Live fish or whole, round**- Live fishes are transported and marketed alive. Whole, round fishes are caught and taken from the water. 2\. **Dressed**- fish is whole fish with scales, entrails, fins and head removed. 3\. **Butterfly fillet**- Butterfly fillet ate the two sides of the fish cut lengthwise away from the backbone and held together by the uncut flesh and skin of the belly. 4\. **Filet**- Fillet is the boneless side of the fish cut lengthwise from the backbone. 5\. **Steaks**- steaks are cross section slices cut from a large, dressed fish; the cross section of backbone generally included. 6\. **Sticks-** Sticks are uniform stock cuts from large blocks of frozen fillets. **Fish Cookery** Fish taste better when cooked. Fish is cooked to destroy ant bacteria present as well as to improve its taste and tenderness. In cooking, moderate temperature is used, long enough for the fish delicacy flavor to develop, for proteins to coagulate and for very small amount of connective tissue present to break down. The flesh of fish is sufficiently cooked when it falls easily into clumps of chalky-white flakes when tasted with fork. When no additional water is used to cook fish, it is important that no overcooking be done. Otherwise the fish would be very dry. This method is known as dry cookery. Broiling, baking, frying and toasting are examples of such method. As a rule, fat fishes are more desirable for dry heat cooking. When moist cookery is employed (fish is cooked in water, it is best to allow the water to boil before plunging or adding the fish) prolonged boiling tends to break the flesh of the fish until it falls apart. Ten to 15 minutes cooking is generally enough time for the fish to be done. Indication of doneness is evident when the flesh becomes opaque and the muscles are easily flaked.