1 of 14

POSTHARVEST TECHNOLOGY�FISH BY PRODUCTS AND THEIR IMPORTANCE IN �HUMAN LIFE�

B.SUJATHA,

GOVT.DEGREE COLLEGE,

RAJAMPET.

2 of 14

Introduction:

Pisces forms the largest class among vertebrate organisms. Fishes provide necessary amounts of proteins to human beings. Fish food constitutes the supplementary food to most of the Indians. Fish meat is easily digestible and highly dependable. Doctors recommend fish meat for quick recovery from kwashiorkor disease (caused by the deficiency of proteins). Though fish is mainly used as food, a number of by products from fishes have great economic value. Biological value for fishes is about 76% and their protein efficiency ratio is 3.5.

B.Sujatha,Lecture of Zoology

3 of 14

By products from fishes:

1. Fish manure: Left over fish, dead and deteriorated fish and unwanted thrown fish etc. are dried and ground to make manure after mixing with ash. Fish cake after the extraction of oils from sardine fishes is popularly called as fish guano. Such manures contain 5-7% nitrogen and 3-4% phosphates which in turn are utilised by the plants and give high yield in agriculture.

B.Sujatha,Lecture of Zoology

4 of 14

2. Isinglass: Air sacs obtained from catfishes, perches, scianids and polynemid fishes are cleaned in water, and the outer layer is removed. Inner layer is flattened and dried. When this soaked in beer, it becomes gelatinous and is called isinglass. It is used to purify beer and wine in distilleries. It is also used in the making of plasters, special grade cements and adhesives.

B.Sujatha,Lecture of Zoology

5 of 14

3. Fish glue: When the fish skin, fins, bones etc. are powdered and cooked for 6-10 hours in acetic acid, the liquid becomes sticky. This is the glue which is used in binding cartoning and carpentry.

B.Sujatha,Lecture of Zoology

6 of 14

4. Fish oils: Two types of oils are extracted from fishes.

(a) Fish body oil extracted from the whole fish is used in the manufacture of paints, antiseptic soaps, candles, leather and steel. These oils are also used to coat the boats as they prevent the wood from the bacterial decay.

B.Sujatha,Lecture of Zoology

7 of 14

(b) Liver oils are extracted from the livers of sardines, sharks, Skates and cod fishes by boiling the liver in water. Purified oils contain large quantities of vit. A and D besides 55-75% fats and 5-10% proteins. These oils have medicinal values and hence are used in pharmaceutical industries.

B.Sujatha,Lecture of Zoology

8 of 14

5.Fish skin: Rough skin of sharks and rays, popularly called ‘shagreen’ is Used in polishing gold ornaments. Tanned skin is used in the manufacture of shoes, bags, money purses etc.

B.Sujatha,Lecture of Zoology

9 of 14

6. Tail fins: Caudal fins of sharks are purified and dried to export for China where they are used in the preparation of soups.

B.Sujatha,Lecture of Zoology

10 of 14

7. Artificial pearls: The shiny material from the scales of fishes is used as internal lining of glass beads. Such coated beads are sold as artificial pearls.

B.Sujatha,Lecture of Zoology

11 of 14

8. Biological control: Larvicidal fishes like Gambusia, Lebistes, Rasbora, Esomus, Chela, Puntius, Berylius, Danio, Ambassis, panchax etc. are release into reservoirs, ponds and tanks to feed on mosquito larvae. This helps in preventing the infection and spread of dreadful diseases like malaria and elephantiasis.

B.Sujatha,Lecture of Zoology

12 of 14

9. Aesthetic value: Gold fishes, silver fishes, black mollies, Etropus etc. are grown in aquaria arranged in houses for decoration etc.

B.Sujatha,Lecture of Zoology

13 of 14

10. Fish Maws: The swim bladder, gas bladder or air bladder is otherwise called as fish maws. It is an internal gas filled balloon like organ contributing to the ability of many bony fish to float or stay still in water to saved energy besides acting as a stabilizing agent. Additionally, the swim bladder functions as a resonating chamber, to produce or receive sound.

B.Sujatha,Lecture of Zoology

14 of 14

In some Asian cultures, the swim bladders of certain large fishes are considered a food delicacy. In China they are served in soups or stews. Swim bladders are also used in the food industry as a source of collagen. They can be made into strong, water-resistant glue, or used to make isinglass for the purification of beer. In earlier times they were used to make condoms.

B.Sujatha,Lecture of Zoology