The composition of fish varies to a large extent and depends on its fat content. Nutritive value of various fish is given in Table.
- Carbohydrate: The shell fish has less fat and more carbohydrate than fin fish. Like meat, fish contain some glycogen in muscle tissues. In the live fish, glycogen is the source of stored energy. Oysters are notable for their high content of glycogen ( on an average of 2-3 percent).
Commonly consumed fish are carp, rohu, sardine, mackerel pomfrets, seer fish, prawns, ribbon fish sole, Bombay duck, catfish and crab.
- Protein: Fish is an excellent source of protein due to its quality and quantity. They contain around 20 % of protein. The biological value of fish protein is 80. Fish is rich in lysine and methionine hence, it has supplementary value with cereals and pulses.
- Fat: Fish contains less amount of fat compared to meat and poultry. The lipid content of both fish and prawns is very low and varies within a very narrow range of 1-2.8 %. Crab small contains nearly 10 % fat. Vanjaram contain 4 % fat. Fish contains saturated fatty acids (40 %) monounsaturated fatty acids (25 %) polyunsaturated fatty acids (n-3-25 % and n-6 -10 %). Fresh water fish contains eicosapentaenoic acid and decosahexaenoic acid which are n-3 polyunsaturated fatty acids. N-3 fatty acid content of some fish is given in Table.
Table : Nutritive value of fish (per 100g)
|
Tamil
Name
|
Moisture
(g)
|
Energy
(kcal)
|
Protein
(g)
|
Fat
(g)
|
Carbohydrate
(mg)
|
Calcium
(mg)
|
Phosphorus
(mg)
|
Iron
(mg)
|
Thiamin
(mg)
|
Ribo
flavin
(mg)
|
Niacin
(mg)
|
Ascorbic
Acid
(mg)
|
Cat fish
|
-
|
77.1
|
86
|
21.4
|
-
|
-
|
10
|
230
|
-
|
-
|
-
|
2.5
|
-
|
Crab small
|
-
|
65.3
|
169
|
112
|
9.8
|
9.1
|
1606
|
253
|
-
|
-
|
-
|
-
|
-
|
Katla
|
Thepu menu
|
73.7
|
111
|
19.5
|
2.4
|
2.9
|
530
|
235
|
0.9
|
-
|
-
|
0.8
|
-
|
Mackerel
|
-
|
77.3
|
93
|
18.9
|
1.7
|
0.5
|
429
|
305
|
4.5
|
-
|
-
|
-
|
-
|
Pomfret black
|
Vavalu
|
74.5
|
111
|
20.3
|
2.6
|
1.5
|
286
|
306
|
2.3
|
-
|
-
|
-
|
-
|
Pomfret white
|
Vavalu
|
78.4
|
87
|
17.0
|
1.3
|
-
|
200
|
290
|
0.9
|
-
|
0.15
|
2.6
|
-
|
Prawn
|
Yera
|
77.4
|
89
|
19.1
|
1.0
|
0.8
|
323
|
278
|
5.3
|
0.01
|
0.10
|
4.8
|
-
|
Rohu
|
-
|
76.7
|
97
|
16.6
|
1.4
|
4.4
|
650
|
175
|
1.0
|
0.05
|
0.07
|
0.7
|
22
|
Sardine
|
Mathi
|
78.1
|
101
|
21.0
|
1.9
|
-
|
90
|
360
|
2.5
|
-
|
-
|
2.6
|
-
|
Seer
|
Vanjaram
|
72.7
|
126
|
22.5
|
4.0
|
-
|
71
|
572
|
5.4
|
-
|
-
|
1.2
|
-
|
Shark
|
-
|
76.0
|
93
|
21.6
|
0.4
|
0.8
|
357
|
262
|
1.4
|
-
|
-
|
2.5
|
-
|
Shrimp
|
-
|
6.0
|
349
|
68.1
|
8.5
|
-
|
4384
|
1160
|
-
|
-
|
-
|
-
|
-
|
Sole
|
Veralu
|
78.0
|
94
|
16.2
|
2.3
|
2.2
|
140
|
95
|
0.5
|
-
|
-
|
0.5
|
9
|
Source: Gopalan, C., Rama sastri B.V. and Balasubramanian S.C., 1991, Nutritive value of Indian foods, National Institute of Nutrition, ICMR, Hyderabad.
Approximate fatty acid composition of fish fats
Saturated fatty acids
|
-
|
40%
|
Monounsaturated fatty acids
|
-
|
25%
|
PUFA n-3
|
-
|
25%
|
PUFA n-6
|
-
|
10%
|
Table: n-3 fatty acid composition of some fish
Type of fish
|
Amount ( g / 100g )
|
Fresh water fish
|
0.07 to 0.28
|
Murrel
|
0.28
|
Pearl sport
|
1.7
|
Mackerel
|
0.39
|
Prawn
|
0.3
|
n-3 fatty acids protect against cardiovascular disease and essential for the development and function of brain and prevents inflammation and pain of arthritis.
Shad
|
Catfish
|
Sea Robin
|
Swordfish
|
Perch
|
SeaBass
|
Fish and Health
Eskimos living in Green land as also the fishing community in Japan, whose daily consumption of fish is 250-400 g enjoy complete freedom from cardiovascular diseases. The beneficial effect of dietary fish is attributed to the fatty acid composition of the fish.
In white fish, any fat present in the fish is stored in the liver. Only minute traces are found in the flesh. Most of the white are sea-water and live an seabed. In oily fish, fat is distributed through the flesh in the muscle fibres. The amount of fat may vary from 8 percent to 15percent.
- Minerals: Fish is rich in calcium particularly small fish when eaten with bones. Marine fish or ocean fish are good source of iodine, selenium and fluoride. Oysters are good source of copper and iron. Sodium content of fresh water fish is slightly less than meat. Shell fishes such as oysters are among the nature’s richest source of Zinc. The bioavailability of iron and zinc is higher than from plant food.
- Vitamins: Sea foods contain significant amounts of vitamin B12 especially shell fishes. Fish liver oils are excellent source of fat-soluble vitamins. Shark liver oil contains 10,000-24,000 IU of vitamin A per gram of oil. Rohu contains vitamin C. Fish are good source of niacin and vitamin D.
Fish protein concentrate
It is the name given to edible fish product suitable for human consumption prepared from fresh fish. The fish protein concentrate, an essentially odourless powder is very rich in protein – 70-80 percent with high lysine content. It has high biological value protein. It is light in colour, free from grittiness and can be incorporated at 3-10 % in a variety of dishes to supplement daily diets.
Fish protein foods developed are fish protein concentrate, non-deodourised fish flour, fish protein enriched corn starch, fish cakes, fish potato flakes, fish sausage and fermented fish products. These products can easily be incorporated into any snacks.
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