Hilsa Regional Workshop Bangladesh Nutritional Values Consumption Utilization Hilsa

Proc. Regional Workshop on Hilsa: Potential for Aquaculture. 16-17 September 2012. Dhaka, Bangladesh

Nutritional values, consumption and utilization of Hilsa

Tenualosa ilisha (Hamilton 1822)

A K M Nowsad Alam1, Bimal P. Mohanty

2, M. Enamul Hoq

3 and Shakuntala Thilshed

4

1Department of Fisheries Technology, Bangladesh Agricultural University, Mymensingh, Bangladesh

2Biochemistry Laboratory, ICAR-Central Inland Fisheries Research Institute, Barrackpore, Kolkata, India

3 Bangladesh Fisheries Research Institute, Mymensingh, Bangladesh

4The WorldFish Center, Bangladesh & South Asia Office, Dhaka, Bangladesh

Abstract

The Indian shad hilsa, Tenualosa ilisha (Hamilton, 1822), is one of the most important tropical fishes in the Indo-

Pacific region and has occupied a top position among the edible fishes due to its superb taste, mouthwatering flavor

and delicate culinary properties. Hilsa is rich in amino acids, minerals and lipids, especially with many essential and

poly-unsaturated fatty acids (PUFA). It is found to be beneficial to human health because of very high level of high

density lipoprotein and low level of low density lipoprotein in PUFA that reduce the risk of heart disease, diabetes,

cancer, obesity, etc. The unique taste of hilsa has been attributed to the presence of many mono and poly unsaturated

fatty acids, viz., oleic, lenoleic, lenoleneic, arachidonic, eicosapentaenoeic and docosa-hexaenoeic acids. Hilsa is

tastier during pre-spawning than post-spawning or maturing stages. Female hilsa grows faster, attains larger and

becomes more tastier than the male of same age group. Riverine hilsa, especially those from the river Padma, are

more tastier than marine ones. Transformation of saturated and mono unsaturated fatty acids into PUFA are believed

to be the key important phenomena that controls the unique taste of riverine hilsa. About 60-70% of hilsa are

consumed fresh in Bangladesh and the rest are exported to India, USA, EU, Japan and the Middle-east. Due to high

price paid in both domestic and international markets, post-harvest handling and icing of the fish are found to be

adequate, while post-harvest loss was minimum, except in some glut catches when ice production can not keep pace

with very high demand. Hilsa is processed through semi-IQF (individual quick freezing), plain salting, salt-

fermenting and wood-smoking. Hilsa is consumed by so many ways with several lovely dishes are prepared as

delicacy, viz., shorshe ilish, bhapa ilish, ilish polao, ilish paturi, panta ilish, etc. The present paper reviews the

nutritional importance, consumption, post-harvest handling, processing and utilization of hilsa as the most popular and

commercially important food fish in the Indian subcontinent.

1. Introduction

Fish is one of the important sources of quality animal proteins and availability and

affordability is better for fish in comparison to other animal protein sources. Fish serves as a

health-food for the affluent world owing to the fish oils which are rich in polyunsaturated fatty

acids (PUFAs), especially ω-3 PUFAs and at the same time, it is a health-food for the people in

the other extreme of the nutritional scale owing to its proteins, oils, vitamins and minerals and the

benefits associated with the consumption of small indigenous fishes (Mohanty, 2011). Fish,

especially saltwater fish, is high in ω-3 fatty acids, which are heart-friendly, and a regular diet of

fish is highly recommended by the nutritionists. This is conjectured to be one of the major causes

of reduced risk of cardiovascular diseases in Eskimos (Bang et al. 1976). It has been suggested

that the longer lifespan of Japanese and Nordic populations may be partially due to their higher

consumption of fish and seafood. Oily fish is claimed to help prevent a range of other health

problems from mental illness to blindness. Thus fish has medicinal and therapeutic value


(Mohanty et al. 2011a) and the health benefits of eating fish are now being increasingly

understood (FISHupdate.com).

Tenualosa ilisha (Hamilton, 1822) of the subfamily Alosinae, family Clupeidae, order

Clupeiformes, is one of the most important tropical fishes of the Indo-Pacific region and has

occupied a top position among the edible fishes owing to its taste, flavor and culinary properties.

Popularly known as hilsa, it is a fast swimming euryhaline known for its cosmopolitan distribution

in brackish water estuaries and marine environment in the Indo-pacific faunistic region and in the

riverine environments where it migrates for breeding. Major catch of hilsa, about 95%, comes

from Bangladesh, India and Myanmar. Naturally hilsa is in great demand globally, specifically in

the oriental world and enjoys high consumer preference. Its high commercial demand makes it a

good forex earner.

Five varieties of Tenualosa sp (T. toli from Malaysia, T. macrura from Indonesia, T.

thibaudeaui from Mekong, T. reevesii from Southern China and T. ilisha from India, Bangladesh

and Myanmar) are found in tropical Asian region (Blaber et al. 1997) out of which T. ilisha and to

some extent T. toli and T. kelee are prevalent in the Indian waters. The normal habitat, age and

growth and trend of migratory habit differ from species to species. Among the five species, T.

ilisha is the major component of fishery in the Ganga-Brahmaputra-Padma river system. In

Hooghly estuary, hilsa, the state fish of West Bengal, accounts for 15-20% of the total fish landing

(Bhaumik 2010). Hilsa, the national fish of Bangladesh, contributes 12-13% of the total fish

production and about 1% to the GDP.

Hilsa is oblong and compressed having 30-33 spine like scutes on abdomen. Difference

between two major hilsa species is very minute. In T. ilisha dorsal and ventral profile of the body

is equally convex, while in T. toli abdominal profile is more convex than that of dorsal. There are

150 to 200 straight to slightly curved gill rakers on the lower part of first arch in T. ilisha, while

gill rakers are curved and number of gill rakers are 80 to 90 in T. toli ( Huda and Haque, 2003).

There are two bundles of muscles on each side of the vertebral column and each of the

bundles is further separated into an upper mass above the horizontal axial septum and a ventral

mass below this septum. In between the upper and lower bundle mass, along the axial septum, a

thick sheet of dark muscles develops, spreading widely on the surface beneath the skin but

extending conically up to back bone (Nowsad, 2010). Branched pin bones extend horizontally

from the neural or hemal spines into the white muscle tissue. Abdominal portion of lower bundles

are devoid of pin bones. Due to pin bones hilsa can not be filleted. Most of the muscle tissue is


white (65-70%). White muscles have lower level of lipids, haemoglobin, glycogen and vitamins

compared to dark muscles. The dark muscle, about 30 to 35 % of total muscle, is located just

beneath the skin, originates from the base of caudal region and extends along the horizontal axial

septum up to cranium. The darkness in muscles originates from the colour due to chemical

combination of haemoglobin with myofibrillar proteins, called myoglobin. Dark muscles are

generally devoid of pin bones and characterized with higher levels of lipids, haemoglobin,

glycogen and most vitamins. Dark muscle also contains more trimethylamine oxide and amino

acids. The high lipid content of dark muscle in hilsa is important because of problems with

rancidity. Dark muscle also inhibits gel forming ability of muscle tissue which is an important

characteristic of fish for heat treated textured foods. The dark muscle primarily functions as a

cruising muscle, i.e., for slow continuous movement, characteristics of migratory species (Huss,

1988).

Due to high lipid content, hilsa can not be sun dried. Therefore, most preferred short term

method of preservation is icing and long term one is salting or salt-fermenting. Some of the hilsa

are frozen. A few are smoked but, although available before, are not found in the market now

(Nowsad, 2007).

High lipid content makes the hilsa very susceptible to oxidative rancidity, along with rapid

autolytic and bacteriological decomposition (Nowsad, 2010). So, adequate handling and

immediate icing for the fish are required. Premium quality fresh hilsa is silver shinny with

transparent watery slime and pleasant odour. There is often found a reddish colouration on

abdominal surface on each side of the fish in the market. Newly caught fish do not have this

colouration. The dark and associated surface muscles are supplied with enormous blood through

network of capillaries, in order to supply energy for continuous movement. The redness appears

after death when a portion of hemoglobin molecule is separated from the blood and flood the

musculature beneath the skin. But the redness is not an indicator of quality deterioration in fish

(Nowsad, 2010).

Hilsa fishery plays a critical role in terms of the generation of employment and income for

those involved, as well as earning foreign exchange for the country. Recent estimates have

suggested that, in Bangladesh alone, about 500,000 fishers catch hilsa; there may be another 2-2.5

million people indirectly involved in the distribution, sale and other ancillary activities like net and

boat making, ice production, processing and export. The present paper reviews the nutritional


importance, consumption, post-harvest handling, processing and utilization of hilsa as the most

popular and commercially important food fish in the Indian subcontinent.

2. Nutritional values of hilsa

Fish contains proteins and other nitrogenous compounds, lipids, minerals and vitamins and

very low level of carbohydrates (Gopakumar, 1997). Protein content of fish varies from 15-20% of

the live body weight. Fish proteins contain the essential amino acids in the required proportion and

thus, improve the overall protein quality of a mixed diet. The superior nutritional quality of fish

lipids (oils) is well known. Fish lipids differ greatly from mammalian lipids in that they include up

to 40% of the long-chain fatty acids (C14-C22) that are highly unsaturated and contain 5 or 6 double

bonds; on the other hand, mammalian fats generally contains not more than 2 double bonds per

fatty acid molecule. Fish is generally a good source of vitamin B complex and the species with

good amount of liver oils are good source of minerals like calcium, phosphorous, iron, copper and

trace elements like selenium and zinc. Besides, saltwater fish contains high levels of iodine also.

In fact, fish is a good source of all nutrients except carbohydrates and vitamin C. Some inland fish

species like singhi (Heteropnestus fosslis), magur (Clarius batrachus), murrels (Channa sp.) and

koi (Anabas testudineus) have therapeutic properties (Mohanty et al, 2011a).

The importance of fish in providing easily digested proteins of high biological value is

well documented. In comparison to other sources of dietary proteins of animal origin, such as

chicken, mutton, pork, beef etc. the unit cost of production of fish is much cheaper. Fish also come

in a wide range of prices making it affordable to the poor. A common man can afford to meet the

family‟s dietary requirement of animal proteins because he has the option to choose from a fairly

large number of fish species available (Mohanty et al, 2012b). A portion of fish provides with

one-third to one-half of one‟s daily protein requirement. This explains how fish plays an important

role in meeting the nutritional food security, especially in preventing the protein-calorie

malnutrition. In the past this has served as a justification for promoting fisheries and aquaculture

activities in several countries. On a fresh-weight basis, fish contains a good quantity of protein,

about 18-20%, and contains all the eight essential amino acids including the sulphur-containing

lysine, methionine, and cystein.

The greatest advantage of *eating fish* is that, unlike meat, it has minimal content of

saturated fat. The most important fat in fish is omega-3 fatty acid. Hilsa is endowed with this


valuable fatty acids and lipids which play a major role in providing pharmaceutical elements for

physiological maintenance of body tissue. The fats found in hilsa are of the unsaturated kind,

which is good for health. Cooked hilsa is known for its easy digestion and is also used as a

recuperating food. Polyunsaturated omega-3 fatty acids (ω-3 PUFAs), EPA and DHA especially

obtained from fish oil are reported to be potential in curing coronary heart diseases, stroke,

hypertension, cardiac arrhythmias, diabetes, rheumatoid arthritis, brain development,

photoreception system, cancer and depression. A 100 g hilsa contain 22.0 g Protein, 19.5 g Fat.

Highest fat content of 20% has been observed in hilsa captured from Mahanadi river mouth, while

it was lower in Narmada catches along Indian coast. Fatty acid profiling of small pelagic fishes of

Sri Lanka have shown highest amount of saturated fatty acids in hilsa shad (5844.5 mg/100g fish

and palmitic acid contributed 3345 mg/100g fish as compared to other pelagic in North-West coast

of Sri Lanka (Edirisinghe et al. 1998).

Table 1. Nutritional value of raw hilsa

Nutrients Value

Calories 309.58

Calories from fat 200.00

Protein 24.72 g/100 g

Total fat 22 g/100 g

Total carbohydrate 3.29 g/100 g

Vitamin C 27.22 mg/100g

Calcium 204.12 mg/100 g

Iron 2.38 mg/100 g

The chemical characteristics of oil extracted from different body parts of hilsa fish showed

variation among different body parts (Table 2). The saturated and unsaturated fatty acids present

in hilsa oil are mainly myristic, palmitic, stearic, palmitolenic and oleic acids. The contents of %

FFA are initially low but increased rapidly on storage at room temperature (Salam et al. 2005).

Table 2. Chemical characteristics of hilsa fish oil extracted from different body parts

Parameters Body parts

Dorsal Ventral Caudal Egg Liver Brain

Saponification value 194.00 194.00 192.00 180.28 180.76 182.24

Iodine value 101.30 102.00 101.40 100.22 126.40 80.70

Peroxide value

(m.eq.O2/kg oil)

8.00 8.60 8.00 9.28 10.00 7.00

Acid value 4.28 4.16 4.30 7.16 12.00 8.72

% FFA (as oleic) 2.14 2.08 2.15 3.58 6.00 4.36


Unsaponifiable

matter (%)

1.66 1.58 1.82 4.60 3.72 7.00

The fatty acids composition of the oil from six different parts of hilsa showed that the

saturated fatty acids present in the oil are mainly myristic acid, palmitic acid and stearic acid. The

unsaturated fatty acids present in the hilsa oil are palmitolenic acid, oleic acid, linoleic acid,

linolenic acid etc. and present in highest amount in egg (Table 3) (Salam et al. 2005).

Table 3. Fatty acid compositions of hilsa oil extracted from different body parts

Fatty acids Body parts

Dorsal Ventral Caudal Egg Liver Brain

C14:0 5.44 5.70 5.50 6.60 5.90 7.24

C16:0 24.70 25.30 24.86 26.40 27.08 22.00

C18:0 6.20 6.32 6.30 5.70 5.00 4.00

C16:1 13.00 12.30 13.11 14.00 12.00 12.18

C18:1 28.32 28.00 28.40 29.78 29.44 26.08

C18:2 1.16 1.10 1.02 2.18 2.20 0.92

C18:3 0.92 0.96 0.92 0.90 1.08 0.82

The fatty acid composition of different size hilsa is given in Table 4. Analysis showed that

medium-sized fish contained the highest amount of unsaturated fatty acids as well as ω-3 PUFAs

(EPA+DHA) and the lowest amount of saturated fatty acids (SFAs). PUFA content was highest

in small-sized hilsa; however, ω-3 PUFA content was lower and SFAs content was higher in

medium-sized fish. In the large-sized fish, although ω3/ω6 ratio was highest, quantitatively they

contained the lowest amount of PUFAs and highest amount of SFAs. Thus on the basis of fatty

acid profiles, medium-sized hilsa is the best followed by the small-sized fish for human health

and nutrition. Myristic acid (C14:0) was the dominant SFA in small and medium size fish

whereas palmitic acid was the dominant SFA in large sized fish. The highest amount of stearic

acid (C18) was found in large sized hilsa, however, there is no significant differences in stearic

acid content of small and medium sized hilsa. Oleic acid (C18:1; n-9) was found to be the major

monounsaturated fatty acid in all three different size fish (Mohanty et al, 2012a). Oleic acid (OA)

is clinically important unsaturated fatty acid with great therapeutic value. It has been reported that

OA suppresses over expression of the oncoprotein (Her-2/neu-coded) p185Her-2/neu

in vitro and a

higher level of OA in breast tissue provide an effective means of influencing the outcome of

breast cancer (Menendez et al. 2005).


Table 4: Fatty acid composition of different size-groups of hilsa (Source: Mohanty et al. 2012a)

Fatty acid Small size

Medium sized Large size

(% of total fatty acids)

Saturated

8:0 0.05±0.04a 0.03±0.03

a

0.03±0.01 a

10:0 0.06±0.02 a 0.05±0.01

a 0.02±0.01

b

12:0 0.41±0.01 a 0.37±0.23

a 0.09±0.03

b

13:0 0.24±0.25 a 0.05±0.01

a 0.02±0.01

a

14:0 38.78±0.12 a 37.77±0.02

b 9.67±0.48

b

15:0 1.69±0.04 a 1.48±0.01

b 0.34±0.12

c

16:0 0.81±0.05 a 0.21±0.06

a 38.26±0.05

c

17:0 0.82±0.03 a 1.05±0.03

b 0.19±0.05

c

18:0 0.24±0.02 a 0.26±0.06

b 8.86±0.16

b

20:0 0.62±0.06 a 0.67±0.03

b 0.20±0.02

c

22:0 0.48±0.09 a 0.45±0.02

a 0.22±0.09

b

24:0 0.43±0.02 a 0.44±0.04

a 0.11±0.05

b

ΣSFA 44.64±0.09 a 42.82±0.07

b 57.99±0.15

c

Monounsaturated

14:1 0.26±0.05 a 0.18±0.08

a 0.07±0.04

b

15:1 0.08±0.02 a 0.05±0.02

a 0.01±0.01

b

16:1n-7 0.06±0.01 a 0.48±0.05

b 0.22±0.06

c

17:1 0.25±0.08 a 0.29±0.09

a 0.07±0.05

b

18:1n-9 26.55±0.51 a 30.66±0.19

b 25.42±0.25

c

20:1n-9 3.47±0.06 a 2.27±0.36

b 1.23±0.40

c

22:1n-9 0.38±0.06 a 0.64±0.02

b 0.09±0.04

c

24:1 0.55±0.13 a 0.78±0.05

b 0.20±0.13

c

ΣMUFA 31.60±0.19 a 35.36±0.20

b 27.59±0.18

c

Polyunsaturated

18:2n-6 0.66±0.12 a 0.88±0.03

b 0.29±0.45

a

18:2tr 2.66±0.11 a 1.84±0.66

b 0.88±0.09

c

20:2n-6 0.13±0.02 a 0.12±0.03

a 0.03±0.02

b

22:2n-6 0.07±0.01 a 0.07±0.01

a 0.15±0.04

a

18:3n-3 2.61±0.06 a 2.23±0.04

b 0.59±0.13

c

18:3tr 0.86±0.16 a 0.68±0.05

a 0.74±0.72

a

20:3n-6 1.11±0.06 a 0.14±0.004

b 0.08±0.04

b

20:3 and 21 0.13±0.02 a 0.17±0.03

b 0.03±0.09

c

20:4n-6 4.66±0.03 a 4.14±0.06

b 1.21±0.33

c

20:5n-3 2.49±0.03 a 2.87±0.09

b 8.22±0.25

c

22:6n-3 8.41±0.01 a 8.95±0.03

b 2.02±0.42

c

ΣPUFA 23.78±0.08 a 22.11±0.25

b 14.75±0.39

c

Σω-3 13.51±0.09 a 14.06±0.05

b 10.83±0.68

c

Σω-6 6.62±0.12 a 5.36±0.09

b 1.76±0.37

c

EPA+DHA 10.90±0.03 a 11.83±0.09

b 10.24±0.57

a

Σω-3/ Σω-6 2.18±0.26 a 2.62±0.04

a 6.41±1.86

b

ΣPUFA/ΣSFA 0.54±0.01 a 0.52±0.02

a 0.25±0.02

b

AI 3.02±0.01 2.77±0.03 2.25±0.55

TI 0.62±0.01 0.59±0.01 1.18±0.02


SFA-saturated fatty acid; MUFA- monounsaturated fatty acids; PUFA-polyunsaturated fatty acids; EPA-

Eicosapentaenoic acid; DHA- Docosahexaenoic acid; AI- atherogenic index, TI- thromobogenic index

2.1 Changes in proximate and fatty acid composition of hilsa

Nutrient composition of hilsa fish varies among their body parts and also in different

habitats. Hilsa from the major landings sites of Chittagong and Kulna, Bangladesh showed that

proximate compositions varied among the different portions of fish body (Shamim et al. 2011).

The protein content was estimated to be 20.56, 21.89, 21.33, 20.87 and 20.50% in the dorsal

portion (Chittagong), ventral portions (Chittagong), caudal portion (Chittagong), dorsal portion

(Kulna), ventral portion (Kulna) and caudal portion (Kulna), respectively. Highest protein and fat

contents were recorded as in ventral portion of fish from the Chittagong region (21.89% and

20.28% respectively).

Proximate composition of the hilsa changes during their anadromous migration in river

Godavari, India (Table 5) (Rao et al. 2012). The variation in the protein content of hilsa during

anadromous migration was not very conspicuous. However, there was wide variation in the fat

content of hilsa during its anadromous migration. The fat content in the marine hilsa was 12.4%.

The fat content increased to 17.3% in brackish water hilsa. The fat gradually decreased in

Godavari hilsa (14.51 to 8.78%). The results suggest that hilsa gains significant fat content in the

brackish water environment. This is in contrast to other anadromous fishes which accumulate fat

in the marine environment and do not feed during their upward migration.

Table 5. Changes in the proximate composition of Godavari hilsa during anadromous migration

to river Godavari during June to November

Proximate

composition

Marine Brackish

water

Freshwater

June July Aug Sep Oct Nov

Moisture (%) 63.5 62.31 64.63 66.3 69.29 66.64

Protein (%) 22.69 18.14 19.92 21.53 20.15 22.38

Fat (%) 12.4 17.38 14.51 11.18 9.83 8.78

Ash (%) 1.43 1.68 1.03 1.15 0.73 1.66

The Godavari hilsa showed decreasing fat content with time. It is likely that fatter fish

move first from the brackish water location to the Godavari barrage. Hilsa must accumulate

energy reserves during their growth phase in the form of lipids, mainly as triglycerides which are

catabolized to provide the energy necessary for anadromous migration and spawning. Jonsson et


al. (1997) reported a decrease in lipid content during the course of upward migration of Atlantic

salmon.

Again the changes in the saturated and unsaturated fatty acid content during migration of

Godavari hilsa were determined (Table 6). The saturated fatty acid (SFA) content was lower in

Godavari hilsa (24.98%) than in brackish water hilsa (36.76%) and marine hilsa (36.03%). The

distinctly higher content of SFA in marine and brackish water hilsa is obvious as the hilsa is

gearing up for migration and storing saturated fat. Even though the total unsaturated fatty acid

(USFA) content of marine hilsa (63.98%) and brackish water hilsa (63.14%) was almost similar,

marine hilsa had higher levels of monounsaturated fatty acid (MUFA) content (52.57%).

Polyunsaturated fatty acid (PUFA) content showed an increasing trend with lowest in marine hilsa

(11.41%) and highest in freshwater hilsa (26.87%). The distinctly higher content of SFA in marine

and brackish water hilsa is obvious as it is gearing up for migration by storing saturated fat. PUFA

content was higher in freshwater hilsa. The results suggest the transformation of fat, towards

PUFA, during the migration of the hilsa. PUFA was formed at the expense of either MUFA or

both SFA and MUFA. PUFA are integral constituents of the cell membranes. The migration of

hilsa from the salty marine environment (30-35 ppt) to the low saline brackish water or zero saline

freshwater environments changes the osmotic balance of the cells. Increased PUFA is necessary to

reorganize the composition of vital membrane to maintain homeostasis. The change in fatty acid

composition of hilsa towards PUFA might be possibly a physiological mechanism to counter the

changes in salinity of water during migration. The study showed that Godavari hilsa is a

nutritionally rich fish with adequate amounts of protein, minerals and fat. Increase in PUFA was

observed during the anadromous migration of hilsa. The nutritional composition of freshwater

hilsa from River Godavari appears to be better than the marine hilsa from Bay of Bengal.

Table 6. Changes in the saturated (SFA) and unsaturated (USFA) fats during migration of hilsa

from marine to freshwater during June to November

Hilsa origin SFA* USFA*

Marine 36.03 63.98

Brackish water 36.76 63.14

Freshwater(Godavari river) 24.98 75.02

*All values are expressed as % fatty acid/total fatty acids

The crude fat content of small, medium and large size fish was found to 6.74-9.43, 8.94-

12.56, and 11.25-17.87%. Substantial differences between the seasons were observed in three


different size groups of hilsa. The highest level of fat content was found during the quarter July–

October (Q1) while lowest during the quarter November– February in all three different size

groups of hilsa. The crude fat content of small, medium and large size fish was found to be 6.74–

9.43, 8.94–12.56 and 11.25–17.87 %, respectively, showing a direct positive relation to the size of

the fish (Table 7) (Mohanty et al. 2012a).

Table 7. Seasonal variation in crude fat content of Hilsa (Source: Mohanty et al. 2012a)

Size/Season July-October

(Q1)

November-February

(Q2)

March-June

(Q3)

(g/100 g of wet muscle)

Small (200-400 g) 9.43 6.74 7.56

Medium (800-1000 g) 12.56 8.94 9.91

Large (1400-1600 g) 17.87 11.25 14.73

Besides fatty acids, hilsa is also rich in amino acids (Table 8). The amino acids are the building

blocks of the body protein. Essential amino acids (EAA) must be obtained from the diet, while

non essential amino acids (NEAA) can be produce from the other source in the body. The major

amino acid in small size, medium size and large size fish are histidine, glutamic acid and aspartic

acid ranging from (5.47 ± 0.41)% to (6.31 ± 0.10)% , (13.06 ± 0.06)% to (15.39 ± 0.22)%,

(10.21± 0.06)% to (11.25 ± 0.40)%, respectively. The level of different amino acids was from

(0.20±0.05)% to (15.16±0.47)% in small size hilsa, (0.95±0.04)% to (15.39±0.22)% in medium

size hilsa and from (0.72±0.01)% to (10.21±0.06)% in large size fish, respectively. Aspartic acid,

glycine and glutamic acid content in small size fish was (10.48±0.04) %, (8.46±0.39) % and

(15.16±0.47) % respectively. The essential amino acids such as isolucine, leucine, phenylalanine,

histidine, lysine, and arginine were (5.35 ± 0.12)%, (9.25 ± 0.33)%, (4.16 ± 0.14)%, (6.31

±0.10)%, (3.22±0.03)% and (1.25±0.13)%, respectively in small size hilsa.

A high plasma EAA-to-NEAA ratio is considered to be an index of positive protein

nutritional status (Swendseid, Villalobos & Friedrich, 1963). The favorable ratio of EAA to

NEAA, about 0.70, indicates high quality protein content (Bandarra, et al., 2004). The highest

value recorded for squid‟s roe (0.93) and was lowest for sea urchin roe (0.65). Amino acid

metabolism also depicts the physiological function of rat plasma and erythrocyte EAA-to-NEAA

ratio showed a positive correlation to IGF-I and insulin whereas an inverse correlated to IGFBP-1

(Filho, et al., 1999).


Table 8: Total amino acid profiles of Tenualosa ilisha. (Source: Mohanty et al. 2011b)

Amino Acid Small Size Medium Size Large Size

(% of total amino acid)

Essential

Threonine ND 6.32 ±0.17a 7.10 ±0.03

a

Valine 6.58 ± 0.81a 6.35 ± 0.21

a 5.80 ±0.81

a

Methionine 3.30 ±0.29a 1.63 ±0.10

b 2.72 ±0.02

c

Iso leucine 5.35 ±0.12a 6.20 ±0.21

b 4.69 ±0.58

a

Leucine 9.25 ±0.33a 9.33 ±0.35

a 8.03 ±0.06

b

Phenylalanine 4.16 ±0.14a 3.71 ±0.42

b 3.43 ±0.38

b

Histidine 6.31 ±0.10a 5.47 ±0.41

b 5.94 ±0.21

a

Lysine 3.22 ±0.03a 2.35 ±0.25

b 10.15 ±0.05

c

Arginine 1.25 ±0.13a 0.94 ±0.03

b 0.72 ±0.01

c

∑EAA 39.42 42.3 48.58

Non-essential

Aspartic acid 10.48 ± 0.04a 11.25 ±0.40

b 10.21 ± 0.06

c

Serine 6.56 ± 0.13a 7.02 ±0.31

b 5.99 ±0.13

c

Glutamic acid 15.16 ± 0.47a 15.39 ±0.22

a 13.06 ±0.06

b

Glycine 8.46 ± 0.39a 9.01 ±0.21

b 8.22 ±0.25

a

Alanine 9.34 ± 0.28a 9.59 ±0.15

a 8.45 ±0.04

b

Tyrosine 1.92 ± 0.54a 1.39 ±0.16

a 0.84 ±0.16

b

Proline 0.20 ± 0.05a 1.34 ±0.39

b 0.91 ±0.10

b

Cysteine 0.32 ± 0.03a 0.95 ±0.04

b 2.11 ±0.06

c

∑NEAA 52.44 55.94 49.79

EAA/NEAA 0.75 0.76 0.98

Values are shown as average ± standard deviation.

ND- not detected, EAA- essential amino acid, NEAA- non essential amino acid

The paramount importance of the hilsa in nutritional point of view is all the more enhanced

by the presence of minerals. These micronutrients play a major role in the metabolic activity of the

human body, by serving as co-factor of enzymes. The macro minerals (Na, K, Ca, Mg) and trace

minerals (F, Cu, Zn, Mn) are present in hilsa in good amount (Table 9).

Table 9: Mineral content in medium size hilsa (Source: Mohanty et al. 2012c)

Minerals Concentration (mg/100g wet weight)

Macro minerals

Na 63.07±5.11

Mg 38.33±8.12

K 695.13±17.25

Ca 119.03±14.56


Micro minerals

Mn 0.28±0.03

Fe 3.06±0.72

Cu 0.31±0.06

Zn 0.96±0.09 Values are shown as average ± standard deviation

Fish is a rich source of vitamins, particularly vitamins A, D, E from fatty fish species, as well as

thiamin, riboflavin and niacin (vitamins B1, B2, B3). Vitamin A from fish is readily available to the

body than from plant source. Among all the fish species, fatty fish contain more vitamin A. The

vitamin content of medium size hilsa (Mohanty et al, 2012c). is given below (Table 9).

Table 10: Fat soluble vitamin content of medium size Hilsa (Mohanty et al. 2012c )

Vitamins Concentration

(µg/100g) IU/100g

A 712.93±0.59 2376.43

D 133.6±0.60 5344.0

E 841545.45±0.47 925.70

K 1163.85±0.62 -

2.2 Nutrigenomics of hilsa

Study of physical structure of fish is important in order to understand the nutrition profile

and quality changes of fish during handling, transportation, processing, storage and heat treatment.

Like other teleosts, in hilsa there are two bundles of muscles on each side of the vertebral column

and each of the bundles is further separated into an upper mass above the horizontal axial septum

and a ventral mass below this septum. In between the upper and lower bundle mass, along the

axial septum, a thick sheet of dark muscles develops, spreading widely on the surface beneath the

skin but extending conically up to back bone (Fig. 1 & 2). Bundles of muscles, mostly upper

bundles, are characterized with huge Y- shaped branched pin bones. Pin bones extend horizontally

from the neural or hemal spines into the muscle tissue (Nowsad, 2010). Abdominal portion of

lower bundles are devoid of pin bones. Due to pin bones hilsa can not be filleted. Patient

separation of cooked flesh from bones is required, that may restrict fish loving people, unfamiliar

to hilsa taste, to eat this fish at the first time. There are two types of muscles: white muscle and

dark or red muscle. Most of the muscle tissue is white (65-70%). White muscles are full of pin

bones and have lower level of lipids, hemoglobin, glycogen and vitamins compared to dark


muscles. White muscle is sprinting muscle in function, used for sudden, quick movements needed

for escaping from a predator or for other reasons. Hilsa has 30-35% dark tissue of brown or

reddish colour. The dark muscle originates from the base of caudal region and extends along the

horizontal axial septum up to cranium. This darkness in muscles appears from the colour due

myoglobin. Dark muscle, generally devoid of pin bones, is characterized by higher levels of

lipids, hemoglobin, glycogen and most vitamins and usually contains more trimethylamine oxide

and amino acids. From technological point of view, the high lipid content of dark muscle in hilsa

is important because of problems with rancidity. The dark muscle primarily functions as a

cruising muscle, i.e., for slow continuous movement (Huss, 1988).

Fig. 1. Hilsa, Tenualosa ilisha. (a) Tenualosa ilisha; (b) Sketch of hilsa showing

distribution of dark muscles along the lateral line (Curtsy: Nowsad, 2010))

a.

b.


Fig. 2. Skeletal musculature of hilsa. (a) Musculature; (b) Sketch showing

the distribution of dark and white muscles (Curtsy: Nowsad, 2010)

Skeletal muscle is the largest organ system in fish and represents the edible part. In fish,

the skeletal muscle constitutes the 34-48% of the total body weight (Addis, 2010). Muscle

composition contributes strongly to quality. In fact texture, elasticity, and water holding capacity,

all features highly related to quality, are dependent on number and integrity of muscular fibres

(Johnston, 1999). The number of muscle fibre recruited during growth is subjected to variation

depending on several factors, such as the fish strain, diet, exercise training and temperature

(Addis, 2010). Muscle proteins are the important repository of much of the biological information.

Since the proteins, not the genes, directly take part in various metabolic processes and

physiological activities depending upon whether it is a structural protein, an enzyme, a signaling

molecule or growth factor or a defense protein like immunoglobulins, they can potentially provide

most, if not all, of the vital information on the organism (Mohanty and Mohanty, 2004; Mohanty

et al. 2005; Ohlendieck, 2011). All the proteins expressed by a cell or tissue or organ comprise the

proteome and study of the proteome is called „proteomics‟. Proteomics is functional genomics,

meaning it focus on those 10% of genes (or gene products) which are expressed/functional; about

90% of genes are not expressed and they are, therefore, not well understood. It is a highly

powerful tool in protein analysis which supplements gene sequence data with protein information

about where, in which ratio and under what condition proteins are expressed.

Proteomics is an unbiased and technology-driven approach for the comprehensive

cataloging of entire protein complements and represents an ideal analytical tool for the high-

throughput discovery of protein alterations in health and disease (Hochstrasser et al., 2002; Martin

et al. 2007). Mass spectrometry-based proteomics is concerned with the global analysis of protein

composition, posttranslational modifications and the dynamic nature of expression levels. The

a.

b.


generation of large data sets on protein expression levels makes proteomics a preeminent

hypothesis-generating approach in modern biology (Cravatt, 2007; Ohlendieck, 2011). Aiming to

better understand proteome alterations, it is vital to have a „reference proteome map‟ for a specific

tissue and species and the muscle proteome map may in fact represent a general „fingerprint‟ of

the fish species (Fig.3. Mohanty, B. P. 2012; unpublished data) (Mohanty et al. 2009; Ohlendieck,

2011).

Tenualosa ilisha is a commercially important food fish species and enjoys high consumer

preference. Proteomics analysis of muscle is an important approach for gaining insight into the

comparative muscle physiology and biochemistry under normal and pathophysiological conditions

(Yi et al., 2008). Skeletal muscle proteomics will also help to establish the global identification

and biochemical characterization of all members of the muscle-associated proteins. For example,

if in hilsa it is found that the medium size fish contains the highest amount of w-3 PUFAs EPA

and DHA, as compared to the small and large size fishes, muscle/liver proteomic analysis at that

stage of the fish can explain why it is so by providing biochemical evidence at the proteome level,

by showing the expression level and quantity/abundance of the enzymes (proteins) elongases and

desaturase (Mohanty et al. 2012a). Thus muscle proteomics and transcriptomics needs to be

studied in detail for understanding the nutrigenomics of this important food fish for optimal

utilization of the health benefits associated with consumption of hilsa.


Fig.3. 1- and 2-Dimensional Gel Eectrophoresis profiles of Tenualosa ilisha white muscle protein extract. 12%

Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) profile and 2-D gel electrophoresis profile.

(Mohanty, B. P. 2012; unpublished data).

2.3 Hilsa for betterment of human health

Fatty acids of fish oil are currently being championed as beneficial for human health

(British Nutrition Foundation 1992). The most efficient way to add these important oils to one‟s

diet is to take at least two/three, servings of fatty fish per week. Hilsa is a highly preferred food-

fish in Kolkata, India, and is always in great demand due to its taste and other culinary properties.

Comparing the fatty acid profile of hilsa with other marine fishes, we found that ω-3 and EPA +

DHA content of hilsa (14.06 and 11.83 %) is higher than that of Indian Mackerel (11.2 and 6.42

%) (Marichamy et al. 2009). Moreover considering ω-6 content, hilsa (5.36 %) also have an

advantage over herring (2.93 %) (Huynh et al. 2007) and Atlantic salmon (3.2 %) (Blanchet et al.

2005). Assuming that hilsa is consumed four times a week and one piece (weight 40–45 g) each

time, the consumption per head per week comes to 160–180 g. The commonly available size of

hilsa in local fish markets varies from 400 to 900 g i.e. medium size. As this size of hilsa contains

1.55 g EPA + DHA per 100 g of fish meat, 2.48–2.79 g of EPA + DHA is consumed per week;

this means, about 354–398 mg EPA + DHA is consumed per day against a requirement 650 mg

per day of these two ω-3 fatty acids, as per the National Institutes of Health, USA as studied by

Mohanty et al. 2012a. However, this projection of the consumption pattern is for the peak seasons,

when hilsa is plentily available in the market. Therefore, hilsa can be a good food supplement for

providing the PUFAs, especially the ω-3 fatty acids. However, there is a line of caution for the

affluent class of consumers who can afford to eat hilsa ad libitum. As mentioned before and as has

been reported by other workers earlier (Rahman and Salimon 2006), hilsa contains higher amount

of SFAs (42.82 %) owing to which it has a higher value for atherogenic index (AI) and

thrombogenic index (TI) and therefore, moderate consumption is good for the heart (Mohanty et

al. 2012a).

Effect of eating hilsa fish in hypercholesterolemic subjects revealed that hilsa fish although

is fatty and contains cholesterol, but it may reduce blood cholesterol level. A study by Quazi et al.

(1994) showed that after 10 months of eating 100g hilsa fish per day, serum total cholesterol level

fell from 285.1 to 244.6 mg/dl (14.2% decrease) in the hypercholesterolemic subjects. The fall in

total cholesterol was exclusively due to fall in LDL-cholesterol. Serum triglyceride, serum HDL-


cholesterol increased in the experimental subjects by 12.5%. On the other hand, serum total

cholesterol, HDL-cholesterol, LDL-cholesterol and triglyceride levels were not changed in control

subjects. Both in control and experimental subjects there were no changes in body weight and

blood pressure during the study period.

3. Why hilsa is called “Macher Raja” – the reasons behind its unique tastiness

Hilsa is considered as one of the most tastiest fish due to its distinctly soft oily texture,

mouthwatering flavour and superb mouthfeel. The fish is locally called “Macher Raja” means the

king of fish.

The human tongue recognizes four basic tastes as sensory responses in different taste buds,

viz., sweet, sour, salty and bitter (Keller, 1985). The sweet taste is sensed at the tip of the tongue,

the salty taste at the tip and edges, the sour at the edges and the bitter at the deep back. Bitter

sensation takes longer time to perceive and tends to linger. Flavour is perceived when volatile

flavor compounds stimulate the olfactory fibers in nasal air passages. Mouthfeel occurs at a

variety of nerve endings in the oral cavity. When tasting, human sensory organs perceive not only

the four basic tastes, but also warm, cold, pain, tactile and pressure sensations. When food is

taken into the mouth, all the sensations are usually recognized to verifying the degree of tastiness

(Keller, 1985).

Konosu (1979) and Konosu and Yamaguchi (1982) reviewed the taste of fish and

shellfishes and concluded that the flavor of fish are distributed to extremely great variety of flavor

compounds that are variable according to species and biological conditions. The nucleus of taste

and flavor in fish is constructed by the synergistic effects of glutamic acid and neocleotides along

with sodium and chloride ions. The core flavor is enhanced by other taste active amino-acids,

mainly taurine and arginine, and nucleotides and inorganic ions. Peptides, organic bases, organic

acids and sugars are also responsible for characteristic taste of some fish species. Flavour

volatiles, lipids, fatty acids and glycogen also play important role in producing overall flavor.

Konosu and Yamaguchi (1985) found large amount of anserine in five species of Atlantic salmon,

a great tasty fish, and suggested that anserine present in the muscle of salmon should play a

significant role in its taste.

The unique taste of hilsa has often been attributed to the presence of certain fatty acids

like steareic acid, oleic acid and many poly unsaturated fatty acids (ω3, ω6 ), viz., lenoleic,

lenoleneic, arachidonic, eicosapentanoeic and docosa-hexanoeic acids (Mohanty, et al. 2011;


Nath and Banerjee, 2012; Madhushudhana Rao et al. 2012). It is very widely accepted hypothesis,

but the correlation between the content of these fatty acids and the tastiness has not been studied.

However, some clues are there that clearly defines a close linkage between the polyunsaturation of

fatty acids and the taste of the fish. Hilsa is tastier just before the spawning than post-spawning

or maturing stages. During pre-spawning time, lipid content in female hilsa generally range from

16 to 22 percent (Mohanty et al. 2011; Madhushudhana Rao et al. 2012). Female hilsa grows

faster, becomes larger and more tastier than the male of same age group. Riverine hilsa, specially

those from the river Padma, are more tastier than marine ones. Several researchers claimed that a

sub-stock of hilsa exists in the Padma river, although many authors described hilsa as a single

stock in the regions shared by Bangladesh, India and Myanmar (BOLME, 2011). Ahmed et al.

(2004) found very distinct genetic difference between Chandpur-Kuwakata and Cox‟s Bazar

population of T. ilisha. The sub-stock of the Padma river might have been rich with characteristic

type of taste-active compounds those impart further taste to this river population.

The taste and flavor of many fish was sometimes depended on their food and feeding

behaviour (Connell, 1975; Love, 1992). Planktonic mollusk, Spiratella helicinia fed by fish gives

rise to an off-flavor in marine fish muscle, often described as „petrol‟ flavor. The larvae of Mytilus

sp. give a bitter taste in herring (Connell, 1975). The texture, colour and flavour of fish flesh

depend on food and feeding habits (Tangeras and Slinde, 1994). The nature of habitat where it

lives also influences the taste of muscles (Huss, 1988). Tastes of cultured pungus, anabas, major

carps, etc differ greatly from wild ones due to the type and quantity of supplemental feed

administered. Farmed salmon are not as colourful due to astaxanthin deposition as the wild one

and therefore receives low price in the market. Salmonids are not able to synthesize astaxanthin

and depend on adequate supply through feed to obtain colour (Foss et al. 1987). Carps from lotic

environment or from big reservoirs impart characteristic taste and color in flesh than carps of

small confined water bodies. The unique taste of hilsa was also believed to be attributed to the

environment where it grazes or to the feed it takes. Hilsa of freshwater origin is tastier than those

of the sea. Godavari hilsa was found to be testier than marine hilsa in Indian waters of the Bay of

Bengal (Madhushudhana Rao et al. 2012). During its time at sea hilsa remains short, thin and less

tasty but when it enters in freshwater its taste and growth increases. Hilsa feed on plankton,

mainly blue green algae, diatoms copepods, cladocera, rotifer, organic detritus, mud, sand, etc.

(Hora and Nair, 1940). The stomach of spawning hilsa was found to contain a considerable

amount of mud and sand also (Pillay, 1958). Hilsa filters planktons but also grubs on muddy


bottom in the sea and brackish water environment (Madhushudhana Rao, et al. 2012). But it does

not feed at all or takes less feed during its further upward migration from brackish waters (Pillay,

1964). During migration it is sustained by the accumulated fat in its body. Therefore, fat content

decreased from the sea to the brackish water, then further to the rivers. Fatter hilsa migrates faster

and losses fats prompter in the rivers. Comparatively lesser fats in the river than their

accumulation in the marine environment makes the flesh more soft and relaxed. During low

salinity directed spawning migration, saturated fatty acids (depot fat) are converted first into

mono- and then into poly unsaturated fatty acids. More the upward migration towards zero

salinity, more the conversion into polyunsaturation was observed in many migratory fish like,

hilsa, Atlantic salmon, chum salmon and sockeye salmon (Jonsson et al. 1997; Magnoni et al.

2006; Sasaki et al. 1989). Probably more the poly unsaturation in fish lipid, more the development

of characteristic texture and pleasant flavour in the muscles. Probably, that is why abdominal part

is tastier than the dorsal, where both lipid content and level of unsaturation are higher (Salam et

al. 2005; Shamim et at. 2011). Polyunsaturated fatty acid content was found to be lowest of

11.41% in marine hilsa and highest of 26.87% in freshwater hilsa (Madhushudhana Rao et al.

2012). Therefore, the transformation of saturated and mono unsaturated fatty acids into poly-

unsaturated fatty acids are believed to be the key important phenomena that controls the unique

taste of freshwater hilsa. More over, among the PUFA, the quantity of docosa-hexaenoic acid

(DHA, C22: 6ω3) was found to be 5.4 times higher than eicosa-pentaenoic acid (EPA, C20:5ω3))

content in Godavari river hilsa, while they were in smaller quantity in brackish water hilsa. In the

sweet-water environment, due to changed osmotic balance from the 30-35 ppt salinity to almost

zero salinity, fish takes more water through mouth, gills and skin to produce and expel large

volume of urine. Thus the musculatory system of the fish gets relaxed, muscle cells become soft

and flexible and the fat-protein inter molecular adjustment becomes more comfortable. As the fish

swims up the river, it flexes it muscles, leading to loss of body fat and makes herself more tasty

(Mondal, 2012). The PUFA acts as the integral components of the cell membrane during the new

osmotic balance in sweet-water system, the conversion of which is necessary to counter the

changes in salinity of water during migration. On the other hand, as the fish does not take food or

take less food while in the rivers, most of the off-flavours imparted in the muscles from the food

and mud in marine/brackish water habitat are eliminated through continuous dialysis by the sweet

water threshold. All these impart unique taste and flavour in the hilsa muscles and make it the

“Macher Raja” – the king of fish.


4. Consumption and Utilization of Hilsa

4.1. Post harvest handling of hilsa

Since hilsa is a high-lipid, rapidly perishable tropical fish, proper handling is necessary to

control and slow down spoilage so that this popular high-priced fish can reach the consumer fresh.

Due to delicate nature and rapid deterioration of muscles, that occurs if treated badly, it is

extremely important to handle this fish very carefully during all stages of transportation, retail

distribution, processing, preservation and marketing.

Fishing gears determines the initial quality of harvested fish (Nowsad, 2010). In

Bangladesh, the crafts and gears for harvesting of hilsa differ from place to place and season to

season. The most effective and popular net for harvesting medium to large size hilsa in marine and

brackish waters are drift gill net, locally called „vasha jal‟ and seine net, called „ber jal‟. Small

mesh mono-filament gill nets, locally called „current jal‟ are mostly used to catch juvenile hilsa in

the river mouth, estuary and brackish waters. Nets are usually made of synthetic and

monofilament fibre. Beside gill nets and seine nets, hilsa is also caught by setbag net, shangla jal

and khora jal or vesal jal (lift net). Usually motorized boats, locally called „trawler‟ are used to

catch hilsa in the sea and river. Motorized boats use inboard engines with capacity ranging from

18 to 65 HP. Generally three types of motorized boats are operated in the estuarine and brackish

water hilsa fishing. Small day fishing boats operating in the estuary or near shore have a

maximum of 4 crews on board. Some boats make a voyage for 3-4 days in the sea with 5-8 crews,

while many large boats of 65 HP engine sail for 10-15 days with number of crews raging from 15

to 18. The boat owners generally hire fishermen to catch fish against pre-set little share of the

catch. Big merchants or „Mahajons’ give cash loan and boats/nets to the fishermen against the

promise to sell the fish to them at tangibly lower price than the market. Mahajons/commission

agents deploy collectors or „bepari‟ to collect fish. They then sell the fish at wholesale markets.

Traders purchase hilsa through the commission agents and transport them to big cities where it is

re-auctioned through second commission agents to the retailers. So the quality of hilsa also

depends on the capital flow, input and infrastructures and the awareness and attitude of the market

actors.

Hilsa was landed in major landing centers in most of the main rivers in Bangladesh

several years back (Haldar et al., 2004). Even during inundation when flood water overflew the


river bank, huge number of hilsa came out from the rivers and found in some beels or haors

(Mazid et al. 2005). Most of those hilsa were marketed locally within few hours and did not

require much care for quality. Upward migration of hilsa declines now-a-days. Haldar et al.

(2004) found hilsa and jatka only in 100 down-stream rivers in Bangladesh. Catch situation is

further aggravated at present. The landing of hilsa is now confined at the lower shore areas of

Meghna river, Tetulia, Kalabodor, down reaches of Arial Kha river, estuary of Dharmagonj and

Nayabhangani river, other estuaries and coastal areas of Bangladesh (Hasan, 2009). Contrary to

freshwater landing, marine landing of hilsa has been increased (DoF, 2011). Hilsa is landed

almost round the year in many landing centers of Teknaf, Cox‟s Bazar, Bashkhali, Chittagong,

Hatia, Patharghata, Kuwakata and Rangabali coasts and Khulna BFDC Ghat (Nowsad, 2010).

Harvesting period also determines the quality of hilsa. Although migrate seasonally to the

rivers during May to October, hilsa are caught in smaller quantity more or less all year round in

the estuary and brackish water areas. The main harvest time of hilsa is August to October. Nearly

60% of total hilsa are caught during this time, with a lesser season between May to June (DoF,

2011). The fishing season varies from area to area. Fishing in the rivers starts from the beginning

of South-west monsoon and continues up to 2-3 months after the monsoon. The winter fishing is

limited and starts from December and continues up to March (Haldar et al. 2004). In the Northern

region hilsa is caught during summer and in the Eastern region it is caught in the winter months.

Dunn (1982) contradicted as saying that there are three peak seasons - one is around February,

another is June and the major peak is September. Due to highly humid hotter climate, majority of

hilsa caught in Bangladesh requires proper handling and adequate icing. As it is sold at very high

price in both domestic and international markets, generally very special care is taken in post-

harvest handling and marketing unless any sudden glut catch disrupts ice supply and other

facilities (Nowsad, 2010). Glut catch occurs one or twice in a year, mostly during September-

October.

Handling of hilsa on-board fishing vessel, at landing and in different steps of distribution

and marketing is more or less adequate (Nowsad, 2010). This is geared partly because of the

awareness developed, but mostly due to the high price in the market. The price of inputs like ice

and fish box is high, adequate transportion is costly, but the traders do not hesitate to afford

because the extra cost can be easily realised through additional price-hiking. This is true for the

big traders and suppliers who monopolize hilsa market. But there are small fishers and fish

traders, where handling of hilsa is not often up to the mark.


Lack of awareness and skill often creates real problem when fishermen do not know how

to behave with their hervest from different gears. Fish in “current jal”, “vasha jal” (drift gill net)

and other gill nets spoil rapidly as they struggle much during fishing. Juvenile hilsa caught in the

coast and river mouths by monofilament –„current jal’ are most susceptable to spoilage. In hotter

months, if not treated with ice, these fish spoil within a few hours of hauling. Field study reveals

that icing in traditional fashion is often sufficient in case of market size hilsa, except during glut

catch when ice supply can not meet the huge demand (Nowsad, 2010).

In traditional hilsa fishery in Bangladesh, fish are bulk-iced in the fish hold of the

motorized artisanal fishing boats. The size of fish holds depends on the size of boat. Generally, it

varies from 10 x 8 feet with a depth of 4-5 feet in 18 HP engine boat to 12.5 x 10 feet with a

depth of 6-7 feet in 65 HP engine boat. Fish are stock-piled with ice in such a big room.

Sometimes, this big room is divided into sections using pound boards supported by stanchions.

During glut catch when the fish holds are full, because of the pressure of huge quantity of fish and

ice from the top, the fish at the bottom of the fish hold are deteriorated rapidly, although they are

kept in ice. To overcome these problems, now small boxes made of plastic or steel and/or empty

plastic drums are used to keep hilsa in the hold. This type of icing is limited to only hilsa and

other high priced species in coastal and matrine fishing.

Large fishing boats operating large drift gill net (8-10 ton capacity) stay at the sea for about

10-15 days. Small boats (0.5-1.5 tons capacity) return to the land within 2-4 days. The boats

generally carry ice block less than their capacity due to high price of ice and uncertainty in getting

fish. For example, large boat carries only about 70-80 blocks of ice, each of 75 kg wight, which is

not sufficient for 6-8 tons of fish to be kept chilled for 10-12 days. Most of the time fish holds are

not full, so the quantity of ice carried do not hamper the quality of icing, except in glut catch

which was found only for a few days in a fishing season.

In Bangladesh, hilsa are iced in different types of containers and trnasported in many ways

(Nowsad, 2010). Majority of the hilsa are transported by bamboo baskets of different shapes and

sizes, with or without hogla mat or polythene covered and with sufficient ices. Fish transportation

by bamboo baskets may cover a distance from a few kilometers to several hundred kilometers and

the content from a few kg fish to several hundred kg. A quantity of 180 to 250 kg are often

transported inter-district by a large size bamboo basket with 2-3 feet elevation made by split

bamboo and polythene gunny sacs. When two of such baskets are placed one top another on the

truck and transported a few hundred kilometers, the quality of fish really goes bad.


Locally made large ice boxes placed one-top-another on the truck are now used by

innovative traders to carry fish from Khulna, Jessore, Chittagong, Cox‟s Bazar and many other

places. These boxes were initially designed to preserve ice blocks and unsold fish in the market

to sell on the next day or after (Nowsad, 2007). These were named community ice box since 5

community traders used the box on community based approach. That technology has been

successfully adopted into bulk fish transportation over the time passed (Nowsad, 2011).

Hilsa landed in Barishal-Barguna-Patharghata-Kuakata-Sundarban coasts are mainly

transported in water-ways by country boat. For this purpose, the open boats are specially

partitioned into several semi-insulated rectangular blocks with or without wood boards, hogla (a

kind of aquatic plant leaves) mat and polythene sheet. Sometimes, styrofoam sheets are placed in

bewteen the wooden boards. The rectangular partition blocks are wrapped with layers of polythene

sheet. Hilsa are kept in these holds with sufficient ice and fish in alternate. Top of the fish are

covered with a layer of ice, polythene and hogla mat. Generally, fish landed in riverine stations

like, Chittagong, Pathaghata, Chandpur or Showarighat of Dhaka city are coming in this way.

Hilsa are also being transported by plastic drum, steel made half-drum, country boat, sac

made of hogla and polythene sheet, aluminium container with or without lid, wooden, fibre glass

or plastic craters, styrofoam box and ideal ice boxes. Post-harvest condition of wet fish along

with percent consumption of harvested fish is shown in Table 11. Hilsa was found to be nicely

handled post-harvest, along with other high-valued species like prawn, shrimp and pomfret.

Table 11. Post-harvest situation of wet fish in Bangladesh (Source: Nowsad, 2010)

Fish groups Pretreatment (% practice) Icing

BCM (%

practice)*1

Process

pattern

Market

pattern

%

consumed

as wet fish *2

Sorting Gutting Washing Dressing/

filleting

Giant prawn 97±1 Nil 95±3 Nil 87±9 Fre/Fro Dom/Expt 19±9

Hilsa 97±2 8±2 77±18 Nil 88±3 Fre/Fro/Salt Dom/Expt 68±5

Pomfret 98±0 Nil 87±12 Nil 91±4 Fre/Fro Dom/Expt 33±8

Bombay duck 22±9 Nil 82±3 Nil 38±5 Fre/Dry Dom/Expt 27±7

Ribbon Fish 27±4 Nil 87±4 Nil 42±8 Fre/Dry Dom/Expt 14±4

Jewfish 65±12 Nil 86±5 Nil 72±12 Fre/Fro/Dry Dom/Expt 18±7

Tuna/Mackerel 69±11 Nil 75±7 Nil 47±7 Fre/Fro Dom/Expt 68±4

Sea bass 78±13 Nil 65±2 Nil 69±6 Fre/Fro/Dry Dom/Expt 73±5

Penaeid shrimp 100 Nil 100 Nil 92±3 Fre/Fro/Dry Dom/Expt 16±9

*1 Icing BCM: Icing before consumer market

*2 Estimated from interview checklist, RRA and RMA data

Fre: fresh; Fro: frozen; Dry: drying; Fer: fermentation: Dom: domestic; Expt: export

Data Source: RRA, SWOT analysis and questionnaire interview of the current study


About 68% of harvested hilsa are consumed as wet fish. Hilsa is brought to the retail markets

with sufficient ice. Hilsa is displayed on large circular aluminium or GI sheet tray with ice around

in the market for sale. Fish those are not displayed are kept in ice box or bamboo basket wrapped

with polythene with sufficient crushed ice around the fish. The fish mongers or nikeries take extra

care for quality maintenance in order to attract buyer and thus demand higher price. Premium

quality fresh hilsa is silver shinny with transparent watery slime and pleasant odour. There is

often found a reddish or pink colouration on the ventral surface on each side of the fish in the

market. Newly caught fish do not have these colour bands. As stated, the redness is not an

indicator of quality deterioration in hilsa.

4.2. Post harvest loss in hilsa

Hilsa is a high-lipid, high-protein fish. In addition, it has 30-35% dark muscles having

higher levels of lipids, hemoglobin, glycogen, vitamins, trimethylamine oxide and amino acids.

These compositions make hilsa very much prone to spoilage at ambient temperature. In hilsa,

rigor comes early, within 15 minutes of death and the fish achieves full rigor within 2 hours at

ambient temperature (33oC). Rigor lasts for 15-16 hours after attainment of full rigor (Haque et al.

1997). After rigor is over, the decomposition of nitrogenous compounds leads to an increase in

pH in the flesh and spoilage starts with autolysis and bacterial action in association with oxidation

of lipids. As the fish is carefully handled by ice during transportation and marketing, spoilage or

quality deterioration is not enormous in hilsa.

The quality loss of hilsa was determined in different steps of distribution channel (Table

12). In estimating quality loss of wet fish, primarily a sensory method (Howgate et al. 1992) was

used where the sensory indicators were rationally revised for getting more accurate results. A

model was developed to standardize sensory data by chemical and microbiological quality

indicators for greater accuracy (Nowsad, 2010). The assessments were conducted in different

steps of its major distribution channels throughout the country for an entire year from March 2009

to February 2010 to find out the seasonal and spatial variations of quality loss. In every

distribution step, at least five lots of fish and 3 individual measurements for each lot were

assessed. The quality deteriorations of the same fish or same lot of fish were assessed during its

movement from the fishermen at harvest to commission agent-1 (commission agent in primary


market) to transporter/wholesaler to commission agent -2 in secondary market to retailer and

vendor. Field data collectors moved along with hilsa from the origin of harvest or landing

through these value chains up to retailers and vendors and assessed the quality deterioration of

same fish or lot of fish in different steps.

In case of determining percent quality loss, the distance of consumer market from origin

was considered and an average of loss due to handling of fish in hotter and colder months was

taken. Neither of the fish lost their quality when they were in fishermen, landing centers or

commission agents in primary fish market. A 2% and 5% loss in hilsa destined for consumer

market as wet fish was, however, recognized in landing centers and Aratders (Table 12). This

might be due to unavailability of ice or transport in glut season catch. Uddin et al. (1999) reported

significant loss of ilish during glut period, mainly in August-September. But these huge catches

cannot be taken care of with adequate supply of fishing boat, manpower for handling, icing, ice

box and transportation. In this time, most of the quality deteriorated hilsa are processed into

salting. Hilsa used for salting suffered a substantial loss while they are in fishermen (14%) or

landing center (43%).

Table 12. Percent quality loss of fish in different stages of distribution channel (Source: Nowsad, 2010).

Fish Month Distanc

e of

market

(km)

% Loss*1

Fisherme

n/

Farmer

Landing

centre

Aratde

r-

1

Transpor

ter/Piker Aratder –

2 /

Processor

Retailer Fish

vendor

Hilsa

(wet fish)

August September

400-

500

- 2±0.4 5±2 - 7±2 9±2 19±4

Hilsa (for

salting)

September 70- 150 14±3 43±5 - - 61±7 - -

Roi February

July 150-

400

- - - 4±2 6±0.4 16±4 19±3

Catla February

August 150-

340

- - - 3±2 4±3 12±3 17±2

Mrigel February July

150-

350

- - - 6±1 7±1 11±3 16±2

Kalibaush February July

150-

400

- - - 4±1 8±2 9±2 12±3

Grass

carp

March

July 150-

350

- - - 3±2 12±3 12±2 14±0.5

Silver

carp

March

May 150-

400

- - - 3±0.1 4±2 13±3 15±3

Tilapia February

May 150 - - - 5±2 11±0.5 16±2 13±2

Pungas June 400-

450

- - - - 4±2 7±3 10±4

Bambay

duck

January April

250 3±0.2 4±0.8 - 11±1 17±2 19±2 -

Ribbon December

February 50 8-10 10-14 20% in drying yard


fish

4.3. Freezing of Hilsa

Both jatka and medium sized hilsa of the glut catch are frozen into block on board in

mechanized trawlers. Small hilsa are packed in polythene gunny sacs in orderly fashion and frozen

into large block, preferably 40-60 kg in the trawler. Frozen blocks of small sized hilsa and jatka

are frozen, stored in land-based cold storages and suitably sold in domestic markets throughout the

country at reasonably cheaper price. Low income people are the major buyers of these small

frozen hilsa. While selling in rural and urban markets, thawing of such large blocks is not

adequately performed, mostly due to negligence. Whereby, sign of muscle distortion, head-cut,

loss of operculum, torn up belly, etc. were observed with deterioration in quality (Nowsad, 2010).

Hilsa exported to foreign countries are frozen whole, mainly in batch type air blast rack

freezer as semi-IQF freezing. Air blast spiral freezer and contact plate freezer are also used. Long

time frozen storage deteriorates hilsa quality due to oxidation of lipid and disintegration of

myoglobin along the lateral line. Oxidation was found to take place in lipid fish slowly even

during freezing and frozen storage (Clucas and Ward, 1996).

Semi IQF of Hilsa

Semi-IQF (individual quick freezing) hilsa are produced in the shrimp processing plants.

After receiving moderate to large sized premium quality hilsa in iced condition, they are weighed,

washed, re-iced, dressed, re-washed with chilled chlorinated (5 to 10 ppm) water (4oC) and

weighed again. Hilsa is not gutted but processed whole for semi-IQF product. Adhered waters

after washing are dried by fanning and then kept naked on SS pans or racks placed on the freezer

pipe of air blast freezer. The fish is frozen at –30oC for 6 hours. Freezing plants that freeze white

fish are equipped with air blast freezing equipment. Exclusive shrimp processing plants generally

do not require batch or continuous type air blast freezer. But hilsa is also processed in

shrimp/prawn processing plants. In the absence of continuous or batch type air-blast freezer,

dressed hilsa are often kept on wire mesh of spiral freezer for freezing. In case of plate freezer,

fish are placed on the freezing tray side by side and frozen as individual unit without making

block. After freezing, the fishes are individually glazed, wrapped by thin polythene sac and

packed in 20 kg carton under various grades like 10/12, 12/14, 14/16, 16/18, 18/20, 20/22, etc


according to buyers demand. A 10/12 grade means that there are ten to twelve fishes in a 20-kg

package. Hilsa are also packed as 1000 g+, 1200 g+, etc. The carton is packed in durable poly bag

and frozen stored at –25oC.

4.4. Salting of Hilsa

Salting is a process of fish preservation where the water content is reduced by the

penetration of salt, whereby the activity of most of the spoilage bacteria is stopped or reduced.

Two basic principles describe the mode of action of salting as well as its importance in

preservation of fish: i. removal of water from the deepest part of the flesh quickly enough to

reduce water activity; ii. penetration of salt quickly enough in the deepest part of the flesh to

lower the water activity (Clucas and Ward, 1996). A concentration of 6-10% salt in fish tissue can

prevent the action of most spoilage bacteria.

4.4.1 Dry-salting of hilsa

In dry-salting, solar salt and turmeric powder are sprinkled over the dressed and cut fish.

In large commercial application, salted fish are piled up in circle in bulk quantity in a big room. In

small-scale operation salt-treated fish are kept in a dry bamboo basket or perforated tin and the

exudates are allowed to run away through the bottom holes. At first, the fish is scaled and the fins

and gills are removed. The fish is cut transversely, from the dorsal to the ventral, by a sharp knife

or „Boti‟ in such a way that the chunks remain attached at the abdominal „keel bone‟ region. The

thickness of the piece ranges from 0.75-1.0 cm. Sometimes one triangular chunk from the neck is

removed to widen the space between the chunks to ease spreading of the fish in crescentic fashion

on the pile. This also helps to ease the mixing and penetration of salt as well as removal of

exudates. Head remains intact with the body. The entrails are removed from the abdomen.

Salt is added to the fish in sufficient amount, in its gills and mouths, in eyes and abdomen

and in between each chunk. One part salt is used for a four-part fish. Along with solar salt, a

small amount of turmeric powder is used to develop a colour in the product. Turmeric has got

preservative value too.

Storage is done in piles as in the case of large commercial production or in bamboo baskets

and tin containers for small-scale production. In both cases, dry-salted hilsa are kept for 3-6

months that allows rigorous changes in sensory properties. There are chances of contamination in

every step of dry salting and the salt used and the salting method itself is not hygienic. The raw


material used was found to be stale, more than 60% of the raw material hilsa lost freshness quality

(Table 12) and hence, the overall quality of the final product was not found good.

4.4.2 Wet-salting of hilsa

In this method, the fish is dressed as in case of dry salting but the head is completely

removed from the body. The dressed fish is either cut into small chunks or kept intact and salted

either in brine or in dry solar salt. For brine salting, the whole fish or chunk is kept in a previously

prepared saturated brine solution. Additional salt is incorporated to maintain the saturation of the

brine as blood, slimes and other exudates of the fish body dilute the brine.

In case of the fish in dry solar salt, the fish is kept in a leak-proof tin container with

alternate salt and fish layers. Sufficient salt is given at the top layer. The tin is covered and kept

for a few weeks in a cool and dry place. The exudates come out of the fish body due to salt

penetration dissolves the surrounding salts and make a concentrated salt solution in which the fish

floats. The ripening comes in within 7-10 days. In either of such wet salting processes, the

removed water, blood, slimes and other exudates cannot pass out but directly mix with the brine

solution, thus forming a complex biochemical high salt mixture that probably helps to develop

characteristic texture, colour and flavour of the wet-salted product.

The keeping quality of wet-salted hilsa was found to be longer compared to dry-salted one

(Nowsad, 2005).

4.4.3 Salt-fermentation of hilsa

Airtight pot is kept underground for 2-3 months. Before filling, the pot is prepared well by

polishing with mustard oil several times and subsequently by sun-drying. Turmeric powder is

sometimes used with salt during fermentation. A semi-fermentation in the fish tissue takes place,

as the muscle softens but the fish remains intact after 2-3 months with the development of a

characteristic texture and attractive flavour.

4.4.4 Under-ground salting of hilsa

Undressed, unwashed hilsa is cut longitudinally along the base of the dorsal fin from the

lumber region up to the cranium. For this purpose, the fish is kept flat on a uniform surface and

the tip of a sharp knife is inserted through the base of dorsal fin up to abdominal cavity. The knife

is extended, parallel to the surface, to the front up to the cranium and to the back up to the lumber

region and the entrails is taken out through dorsal opening. The fish remains intact along the

ventral line. Salt is put inside the fish muscle and in the abdomen through the dorsal opening.


Sufficient salt is pressed in the gills, eyes and mouth and on the body surface. A 2 x 2 x 3 feet

deep hold is dug in the floor under a shed where rain water cannot enter. The underground hold is

protected all around inside with a mat made of split bamboo, locally called “chatai” and a

polythene sheet. Salted fish are kept in layers in an orderly fashion in the hold and sufficient salt

is given in between layers. When the hold is filled up with fish, it is covered by a final layer of

salt and a mat is placed on the top. The top surface of the hold is covered with a clay layer of

about 1 feet and heavy objects like stone, wood-block, brick, etc. are kept on the surface to press

the fish from the top. The mouth of the hold is always maintained 1-1.5 feet high from the floor.

As the hold is dug under a shed it remains protected from the rain. Open shed (no fence around)

also keeps the underground hold cool and dry. The exudates come out of the fish due to salt

uptake are absorbed by the surrounding soil. After 1-1.5 months, the flesh becomes slightly

reddish and off-flavours due to pre-processing spoilage disappear with the development of a

characteristic attractive flavour. The final product becomes more flattened, wider and longer than

the unsalted one.

4.4.5 Salt-fermentation of hilsa in basket

Salting in the underground hold generally requires a large quantity of fish. To process

small catch, however, hilsa

is salted and aged by semi-

fermentation in bamboo

basket instead of earthen

hold. Hilsa is prepared as

the same way as in the case

of underground hold and

kept in layers in polythene

sheet with sufficient salt all

around. Finally, the

polythene is closed well

and kept in a woven

bamboo basket for 1.5 to 2

months. Fig. 4 Aging of hilsa after dry-salting in Chittagong (Curtsy: Nowsad, 2010)


A small mat covers the basket and heavy stones or bricks kept on the top press the fish inside the

basket to release exudates. Polythene sheet that covers the fish is punctured at the bottom to

allow exudates to drain out. The product is opened after 1 month and more salt is added if

required.

4.4.6. Maturing or ripening in salted fish

Maturing or ripening is a physico-chemical process where a characteristic texture and flavour are

developed in salted product due to complex autolytic, enzymatic and microbial actions. In either

of dry or wet salting, salt uptake and water removal do not continue indefinitely; sodium and

chlorine ions form a water binding complex with proteins which exerts an endosmotic pressure

that eventually balances the exosmotic pressure due to surrounding brine and equilibrium is

reached. Under this equilibrium state, within 8 to 15 days of salting, depending on the species and

size of fish, a maturing or ripening occurs in salted products (Horner 1992). Having lost up to

20% of its weight through exosmosis of water to the brine, Hilsa regains original weight through

salt uptake within 10-12 days. The enzyme responsible for maturing is derived mainly from the

digestive system of the fish, the fish muscles and bacteria growing on the fish and in the salt. The

products of proteolysis and lipolysis are also predominant in the ripened products. Lipolysis and

oxidative rancidity play an important role in the flavour development of salted fish products. The

products of Maillard browning reactions also make a significant contribution to the flavour of wet

salted fish (Jones, 1962). In dry-salted hilsa, however, any browning is undesirable and can

render the product unfit for sale.

Various researchers studied the quality of ripened products produced under different ways,

in order to improve the traditional hilsa salting practice. Siddiqui (1993) found that the shelf-life

of salted hilsa packed in polythene bag and preserved at 4°C had better quality than those kept in

room temperature. Khan (1993) studied the changes in physical, biological and microbial quality

of dry-salted, wet-salted and sun-dried & salted hilsa prepared in laboratory conditions and found

that the combined curing method of sun drying and salting produced more attractive yellowish

color with characteristics odor compared to those produced by the traditional and other laboratory

methods. While comparing the four types salted products, Mustafa et al. (2012) found better

quality in the order of mixed salting > dry salting > pickle salting > brine salting. Rahman (1996)

found a considerable loss of lipid during salting, in addition to moisture loss, but essential amino

acids were found unchanged. Salted hilsa showed significant variations in the amino acid profile


of the product as compared to that of raw hilsa as shown in Table 13 (Majumder et al. 2005). This

might be due to the formation of derivatives of amino acids such as amines and gluconeogenic

substances. Lysine was reduced to a great extent, while cysteine was not present or detectable in

the product.

Table 13. Amino acid composition (g amino acid per 100 g protein) of salted hilsa

Amino acids Raw hilsa Salted hilsa % Loss during ripening Aspartic acid 9.93 7.27 26.7

Threonine 4.11 3.31 19.4

Serine 3.37 2.67 20.7

Glutamic acid 16.59 11.21 32.4

Proline 0.99 0.72 27.2

Glycine 4.59 4.51 1.70

Alanine 6.34 5.03 20.6

Cysteine 0.68 ND 100

Valine 4.65 3.66 21.3

Methionine 1.56 1.44 7.70

Isoleucine 4.04 3.10 23.2

Leucine 7.91 5.70 27.9

Tyrosine 1.58 1.57 0.63

Phenylalanine 4.09 2.88 29.6

Histidine 3.58 1.86 48.0

Lysine 11.52 3.72 67.7

Arginine 4.39 3.49 20.5

Tryptophan 1.17 1.05 10.2

4.4.7 Problems of hilsa salting

Hilsa is a dark-fleshed high lipid species. Icing is an effective short-term preservation

method for the fish. Sun-drying cannot be performed for the species because of atmospheric

oxidation or rancidity problems. Long term chilling and freezing are not useful due to texture

degradation for spoilage of dark muscles. Considering the compositional characteristics of the

species, comparative advantage and acceptability of different fish preservation methods and socio-

economic conditions and food habit of the local consumers, salting seems to be the best suited

method for the preservation of hilsa. The following problem, however, have been found to be

associated with the process and the products (Nowsad, 2010):

i. The producers do not follow the regulations regarding public health and sanitation.

ii. In glut period, the fish only those are spoiled or partially spoiled and cannot be sold in the

fresh wet fish market are used for salting.

iii. The fish or the cut pieces are not washed before salting in most of the cases.


iv. The raw material is contaminated by pathogens or other bacteria during scaling, gutting,

dressing and cutting by unclean knife, container or tools.

v. Low quality solar-salt is used that inhibits the development of good texture, attractive

colour and nice flavour of the product.

vi. Salt:fish ratio is not properly maintained. So rancidity occurs in fish during dry salting.

vii. Sometimes excess salting may denature protein and impact upon the sensory and

biochemical properties of the final product.

viii. In wet salting, cut pieces are often floated on the surface of the brine, come in contact of

air and become rancid.

ix. Semi-fermented ilish is not always well protected in the underground hold. Rain water and

mud enter and insects and rodents attack and spoil or contaminate the products.

x. Packaging and storage are not appropriate and hygienic. Very often rancid off flavour

develops in the products those are kept in the basket for long time.

4.4.8 Post-harvest loss in salted hilsa

Post-harvest loss was estimated in 2 types of salted products, i. dry salted hilsa and ii. wet

salted hilsa (Nowsad, 2010). In both cases, 60% of the raw material lost their quality. Pre-process

(handling, washing) and in-process (dressing, cutting, salting, piling, etc.) losses ranged between

5-7%. Quality losses in final products were 65.6% and 67% respectively in dry and wet salted

hilsa. Wet salted chunks were found to float up on the surface of the brine in salting container and

become rancid due to partial contact with air. This might be a reason of comparative higher

qualitative loss in wet salting. There was no quantitative loss found during packaging of wet salted

hilsa and also, the transportation, storage and marketing loss were minimum (2.5%, 2.8% and 2.3

% respectively). Therefore, the total quantitative loss in wet salted hilsa was only 7.6%. The

reason behind such little loss in wet salting might be due to lesser chance of drying-up the product

during in-process and post-process operations, compared to dry salting. Quantitative loss in dry

salted hilsa was 23.2%, might be due to wet loss in storage and during marketing. Storage and

marketing loss was estimated to be 12.2% and 5.4% respectively.

4.5 Smoked Hilsa


With present day‟s reduction of the catch and increased availability of ice, the extent of

smoking of the species has been reduced significantly. Higher price paid for wet fish might be

another reason for such reduced smoking. This product is no longer found in the market. But

local people of Teknaf have been found to prepare this delicate dish at home for own

consumption. Brilliant colour and delicious flavour have made it one of the cherished food items

and a delicacy in this area.

4.5.1 Smoking process

For smoking, the fish is scaled and gutted and then thoroughly washed with clear sea

water. Washed fish is split through dorsal lining to widen and expose the anterior part to smoking,

keeping the ventral lining of the fish intact. After 3-6% salt treatment, split fish is fixed in between

two triangular frames made of split bamboo. The fish is so fixed in order to handle and turn it

easily on fire or smoke that allows uniform smoking. Sometimes, fishes are framed by triangular

fine mesh made of split bamboo. Bamboo mesh is used mainly to frame small hilsa. Now, the

framed fish is kept on the narrow-meshed smoking rack made of split bamboo in such a way that

the anterior split portion of fish receives smoke directly. The smoking rack is placed 2.5 feet

above the earthen oven. Smoke is produced by local woods. No flame but only smoke is allowed

and if any fire breaks out, it is stopped immediately. Fire burns the flesh and develops a brittle

texture of muscle that comes out of the bones. But exclusive smoke makes the texture rigid and

elastic that is relished by the consumers. Green or semi green woods are used for intense smoke.

Smoking is done in a two-step process. In the first step, smoking is done for 4-5 hours. For good

quality and longer shelf life, the product is again smoked for 2 hours after 2-3 days of first

smoking. Due to such repeated smoking, the bones are softened. The final product becomes

brilliant red inside (split part), while the upper surface (skin part) remains transparent. Products

within the triangular frame are stored or marketed as such. Storage is done in open-mouth big

basket made of bamboo split, locally called lai.

Field study suggests that smoked hilsa has already gone to the oblivion memory because of

the easy availability of ice and development of other low-cost improved preservation methods

(Nowsad, 2007). Improvement in the quality and adequate but lucrative packaging might be

necessary to regain their importance in the competitive markets. Attempt has been made to

produce smoked hilsa as a ready food item. Smoked hilsa made from 10% salt and garlic resulted

quality product than fish treated with 10% salt, garlic and coriander, and only 10% salt. Smoked


hilsa contain 39.65% moisture, 25.65% protein, 24.85% fat, 3.5% ash and 16.2% salt (Hossain et

al. 2012).

5. Hilsa Consumption

Fish is not only important for human nutrition; it is also part of the Bengali culture. Fish

demand remains unmet, and fish consumption is still below the recommended dietary allowance.

After a dramatic increase in aquaculture production during 1980s and 1990s, the pattern of fish

production and the shares of different species in national production have remained relatively

unchanged during the last decade. In many developing countries, official national statistics on per

capita fish consumption are commonly based on the total availability of commercial fish in the

country and do not include the consumption of many small and non-commercial fish species

obtained from the artisanal and subsistence fisheries. It is generally assumed that actual per capita

fish consumption is higher than the national average reported in official database (Dey et al.

2005).

Fish consumption in Bangladesh varies across different income groups. For example, the

monthly consumption of the bottom income quartile is only 1.10 kg/capita, which is less than half

that of the highest quartile group. Fish consumption also varies across different types of

consumers. Urban consumers appear to have the highest fish consumption (1.96 kg/capita/month),

followed by producer consumers (1.92 kg/capita/month) and rural consumers (1.69

kg/capita/month). As for specific species, the highest consumption is of assorted small fish,

accounting for 29% of the total fish consumption. This is followed by Indian carp (22%) and

exotic carp (21%). The shares of the other species are: 9% for hilsa, 7.6% for live fish, 4.7% for

tilapia, 4% for shrimp and prawn, and 3.5% for high-valued species. There is a seasonality pattern

of per capita fish consumption, which is in inverse relation to the weighted average price of fish

supply. Expert for shrimp and prawn, all species similarly follow the seasonal patter (Fig.1). The

assorted small fish, which are mostly from freshwater capture fisheries, seem to be major driving

factor for this seasonality pattern, followed by cultured Indian carp and exotic carp.

However, consumption can vary very substantially depending on income, season and

location. Dey et al. (2010) report that an average consumer in the poorest quartile consumes just

39% of the fish consumed by an average consumer in the richest quartile. This indicates that

consumption choices are closely linked to the price of fish; poorer consumers buying cheaper

species, and fish of smaller sizes or of poorer quality. A survey of 150 consumers in Dhaka


conducted by the WorldFish Centre in November 2010 (Fig. 1) reveals a number of interesting

patterns with respect to unban fish consumption. This is also the case for quantity consumed.

When consumption is disaggregated further by origin and species some interesting patterns

emerge. Medium sized freshwater capture species and hilsa (including jatka) are the first and

second most important categories of fish, being eaten in large quantities by consumers in all

income groups. Cultured fish accounted for 31% of total consumption at the time of the survey.

When cultured fish are broken down into their composite species it is evident that Indian major

carp, pangus and tilapia account for three quarters of total consumption, each with an almost equal

share. Exotic carps, including silver carp, account for only 8% of the total, behind climbing perch,

which accounts for 12%. This points to an emerging division between rural and urban

consumption patterns, suggesting a tendency for high value wild fish and commercially cultured

species (pangus, tilapia and climbing perch) to be exported from rural areas to Dhaka, while

cultured carps are mainly consumed in rural areas. This conclusions also appears to be supported

by a survey of markets conducted during the research that informs this report, which indicated that

a smaller farmed fish (roi, silver carp, etc.) and small capture fish (puti, baim, etc.) are the most

commonly available species in rural markets, while larger farmed and wild fish are more abundant

in urban markets.

Delicacy in hilsa dishes

About 68% of the harvested hilsa are consumed as wet fish. Cooking methods applied for

the fish in Bangladesh and West Bengal of India are often common. Some of the highly preferred


dishes are shorshe ilish, bhapa ilish, ilish polao, ilish paturi, bhaja ilish, panta ilish, etc. Some of

them like shorshe ilish, bhapa ilish or ilish polao are of great delicacy, often cooked to celebrate

special occasions in Bengali culture. Panta ilish - a traditional platter of congee with fried hilsa

slice, supplemented with dry fish pickles, sour fruit pickles, varieties of pulses (dal), roasted leaf

vegetables-like jute, green chili and onion - is a popular serving for the Bengali New Year‟s Day

(Pohela Boishakh) festival.

6. Epilogue

The oily fish hilsa is known worldwide for its unique flavor and delicious taste that last for

long time. It possesses an aroma of its own. Hilsa is very favourite fish for its easily digestible

proteins (amino acids), fatty acids like omega-3 fatty acids triglyceride, vitamins like vitamin-D,

vitamin-A and some members of vitamin-B family and minerals like selenium, zinc, phosphorus,

calcium and iron. Like salmon, hilsa is also a rich source of omega-3 fatty acids such as EPA and

DHA, although the PUFA content is lower as compared to salmon. Hilsa is also known for its

appetizing and culinary properties. The highly nutritive and culinary properties of hilsa amply

justify the adage „macher raja ilish‟. This also makes hilsa a strong candidate for aquaculture and

justifies the urgency in standardizing the breeding technology and management practice for this

prized food fish for early domestication.

7. Acknowledgements

Some of the data used in this paper were generated under the ICAR-sponsored Outreach

Activity on Nutrient profiling and evaluation of fish as a dietary component (BPM). Data on post

harvest handling and processing of hilsa were the outcomes of the research project, “Post-harvest

loss reduction in fisheries in Bangladesh-A way forward to food security”, funded by the FAO

(FAO-NFPCSP-PR#5, 2008).

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