REDUCTION OF AMMONIA CONTENT OF SHARK FISH

REDUCTION OF AMMONIA CONTENT OF SHARK FISH
(Carcharhinus limbatus) BY SOAKING IN TAMARIND SOLUTION
AND STEAMING IN DIFFERENT TIME BEFORE DRYING**
J.A. Sumardi 1 and Hardoko 2
ABSTRACT
Research to reduce ammonia content of shark fish flesh has been done by soaking
in vary of tamarind solution, followed by cooking in different time before dried. The
research designed by fully randomized design, where the concentration was 5, 10, and
15%, respectively. While the second factors were cooking time e.g. 5, 15, 25 minutes.
Finally the first of shark fish were dried in 40 - 50°C for six hours. The final product was
analyzed by moisture, protein and ammonia, pH value, Aw, and sensory test.
The result shows that the concentration of tamarind solutions give a significant
different in ammonia content, pH value and sensory test, While cooking time give a
significant different to the Aw and give significant different (p<0.01) of moisture content,
protein, ammonia, appearance, texture, aroma, and taste. Combination of those factors
give a significant difference to the protein content. The greatest ammonia reduction
was in 15% of tamarind solution. The cooking in 25 minutes give the best of sensory
evaluation, e.g. texture, aroma, and taste. The lower concentration of tamarind solution
has a lower ability to reduce ammonia content in flesh of shark fish. The best product
was achieved by soaking in 15% tamarind solution and dried.
Key words: shark fish, ammonia, tamarind
INTRODUCTION
Potency of sharks in Indonesia and from year to year production always
mount, mean production during five year later (1999 - 2004) reaching 63.281
ton/year and most of shark be caught by means of fish long liner, but there are
also caught with net such as gill net appliance or because shark do not any
peak season. There are very rare the shark caught by means of trawl net and
purse seine. Catch production of shark in Indonesia during the time is especially
addressed to obtain its fin, made as a commodity export at the price of very
costly. Besides its fin a species of shark be exploited primarily for its liver to be
1
7
"
Fisheries Faculty of Brawijaya University
Fisheries Faculty ot Brawijaya University dan Dept. ot Food Tech. UPH
Pernah disampaikan dalam Asean Food Conference 8-10 Agustus 2005
Jurnal limu dan Teknologi Pangan, Vol. 3, No. 2, 0ktober2005
79
taken by its oil that containing A vitamin. Shark of this species is recognized
as bottle shark or spiny dogfish (Squalus acanthias)
Flesh of shark which from the beginning was not reckoned by economically
value, nowadays begin be exploited to be consumed by the more important
for some certain area, whereas other area represent abstention if consuming
shark flesh. Generally flesh of shark processed to become salted product then
dried which then sold. Evaluated from flesh chemically composition of shark
much the same with flesh of other marine fish, in every 100 g flesh content of
moisture 74, protein 22, fat 0,3 and ash 1,7 percent. While its liver contain of
moisture 37, oil 52 and ash 1 percent respectively.
Factors becoming constraint to consume flesh of shark is odor of ammonia
sharply (urine like) so that less be taken a fancy to by consumers besides
because of any reason: such as abstention. Aroma of because certain reason
for example, the ammonia or urine like smell come from breaking down of urea
by enzyme yielding ammonia of moment happened by process of degradation
of quality of shark flesh. In line with economic growth now, however, hence
consuming of shark flesh have non matter which the taboo even have been
done by a various means to lessen odor of ammonia in order to earn the more
amount consumed to consider that its protein content. Many fishermen and
processors of fish in some places have exploited flesh of shark by cutting flesh
become cutting piece by piece later; then cutting of flesh grilled or smoked
here in after sold as flesh of shark grilled/smoked, for example in: Sendangbiru
(South of Malang regency), Prigi (South of Trenggalek regency), Popoh (South
of Tulungagung regency), Brondong (North of Lamongan regency), Muncar
(East of Banyuwangi regency) and Puger (South of Jember regency).
High content of urea and ammonia odor in shark flesh, can be slowed down
for example by: (1) making cool fish immediately after caught and after gutted
(removed viscera content, bowels, gill, and lead), at one blow to release its
blood, (2) cutting flesh and heating in order to discontinued enzyme activities,
(3) salting and sun drying, and (4) giving chemical substance (acid) to fasten
ammonia.
This research aim to reduce of ammonia content in shark flesh, by immersing
in vary of tamarind solution, then steaming in different time followed by drying
in a mechanical (electrical) dryer.
MATERIALS AND METHODS
Materials
Material for this research is white shark flesh (Carchrarinhus limbatus),
that obtained from fish auction: Tempat Pelelangan Ikan (TPI) Sendangbiru
(South of Malang regency) about 45 kilometers south of Malang. Fish taken
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Jutnal llmu dan Teknoiogi Pangan, Vol. 3, No. 2. Oktober 2005
by its flesh only and cut into pieces later then iced in box by same portion
between fish and ice. The fish then brought to laboratory (Technology of Fishery
Products) of Fishery Faculty, University of Brawijaya .
Other material used in the research was: tamarind (Tamarindus Indica)
for soaking solution flesh of shark. While chemicals used for analyses were:
sulphuric acid, potassium iodide, mercury chloride and natrium hydroxide
grade, potassium natrium tartrat, boric acid, sulphuric acid 1/70 N, formalin,
indicator tashiro, PP, methyl red, alcohol 96 percent.
Methods
The research was designed by completely randomized compiled by
factorial, and repeated by three of times. Main factor is tamarind concentration
for soaking of shark flesh consists of three levels e.g: 5,10 and 15 respectively.
Second factor was duration of steaming after soaking in tamarind solution,
consists of three levels e.g.: 5,15 and 25 minutes respectively. All steps of
process in the research can be presented in figure 1 diagram.
pieces of shark flesh
1
washed in current water
1
soaked in 5% salt solution
(in 5 minutes)
•
rinsed and drained
1
soaked in (5, 10 aned 15 %) tamarind solution
(in 15 minutes)
1
soaked in 5 % of salt solution
(in 2 minutes)
i
1
drained
steamed at 100 °C
in: (5,15 and 25) minutes
1
drained
i
dried at 45 °C, in 6 hours
i
Final product
Figure 1. Diagram of research execution
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81
Fish processed by the following steps: firstly, flesh of shark cut into pieces
thickly 0,5 cm then washed in well water ton minimize of slime and blood. After
divided into three groups, herein after each group was soaked in tamarind
solution as according to level concentration that were: 5, 10 and 15 minutes.
After finishing soaked, each of three groups then divided again become three
sub-group, what was steamed into a different time that were: 5,15 and 25 minutes,
thereby altogether there were nine sub-group pf samples. For all samples after
had been steamed then altogether dried in a mechanical/electrical dryer for about
six hours, which were equivalent with one day sun drying. The process was
repeated for three times so that totally obtained 27 samples of dried shark
flesh or final products. Hereinafter the final product were analyzed cover: (1)
total volatile bases (TVB), (2) trimethyl amine (TMA), (3) moisture content, (4)
protein content, (5) ammonia content, (6) value of pH, (7) water activity ( a j
and (8) sensory analyses covered: appearance, texture, aroma (odor) and
taste. Meanwhile for comparing level of ammonia content, fresh flesh shark
also was analyzed of TVB and TMA to know what level of freshness of fresh
shark flesh.
RESULTS AND DISCUSSION
Results of chemical analyses to final the products (salted dried shark)
presented in table 1.
Tables 1. Results of analyses cover contents of: moisture, protein,
ammonia, values of (pH and a ) of final products and fresh of flesh shark.
A
5
10
15
Fresh flesh
Moisture
Protein
(%)
Ammonia
(mg/100g)
pH
Aw
B
(%)
5
10,6
86,9
3,7
6,5
0,580
TVB
mgN/
100q
!t^
Treatments
2,3
15
10,3
83,5
3,5
6,3
0,557
25
9,6
80,4
3,4
6,4
0,550
5
10,5
87,7
3,4
5,9
0.607
15
10,1
82,8
3,3
5.9
0.563
25
9,6
78,8
3,0
5,7
0,540
5
11,1
85,3
3,4
5,6
0,600
15
10,0
81,6
3,0
5,3
0,583
25
9,7
80,3
2,9
5,1
0,560
-
81,5
18,2
15,7
6,9
0,934
18,4
Notes: A: Concentration of tamarindus indica solution for soaking (in %)
B: Duration of steaming (in minutes)
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Assess fresh TVB and TMA shark flesh showed 18,4 and 2,3 mgN/1 OOg
respectively. The condition showed that fresh shark flesh that which processed
still be in god condition. Stansby (1986), stated that level of fresh content TVB
and TMA fish flesh was equal to (4,1 - 9,2) mgN/1 OOg flesh, and expressed to
decay if content of TVB reach its 36,8 mgN/100 g and content of TMA equal
to5,35 mgN/1 OOg.
Initial of moisture content of fresh shark flesh showed 81,5 per cent, later
then after processed by soaking in tamarind solution followed by steaming
later then dried, mean of moisture content become equal to 10,2 per cent.
Without considering a difference of tamarind solution for soaking of shark flesh,
a different time of steaming give influence highly significant to the moisture
content of final product, due to the different time of steaming affected to the c
contraction (because of protein coagulation affected by heat). Since the flesh
contracted moisture in the flesh squeezed out of flesh, the longer the heat
influenced to the flesh the more moisture squeezed out of the flesh so that the
moisture content much more drained out and the rest in the flesh decreased.
Protein content of shark flesh before processed by the level of 18,2
percent (wb) or equal to 98,4 percent (db). After processed to use combination
soaking in tamarind solution and steaming later then dried, its protein content
decreased to become 87,2 per cent (db). Difference level of steaming give
high significantly influence to protein content (P<0,01). The more time depth
obstetrical steaming of its protein the more to decrease. As showed from that
tables that product of result of soaked in 10 per cent tamarind solution and
steamed by 25 minute, obstetrical of its protein is the lowest, did not significantly
influence with result of soaked in 15 tamarind solution and steamed by 25
minutes. Obstetrical degradation offish flesh protein during process anticipated
by because most shark flesh protein consisted by dissolve protein globular in
watery acid and water and also easy to experience of degradation.
Content of ammonia of flesh of shark which still be fresh is equal to 15,7
mg/1 OOg, after processed to use tamarind solution and steamed followed by the
draining, obstetrical mean of its ammonia omit equal to 3,3 mg/1 OOg. Without
considered duration of steaming processed, the difference of concentration
of tamarind solution for soaking, really have an effect on highly significant to
the degradation of ammonia (p<0.01). The higher concentration of tamarind
solution has stronger ability to reduce of ammonia content. The difference of
tamarind concentration for soaking e.g.: (5, 10 and 15 per cent), to content
of ammonia of final products successively equal to 3,5; 3,3 and 3,1 mg/1 OOg.
Obstetrical degradation of the ammonia anticipated by because base ammonia
will react with acid form salt ammonium, so that an aroma urine like becoming to
decrease (Considine, 1982). Tamarind has energy of big enough reduction to
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83
urea and able to mellow flesh so that urea will be dissolve in water. Its exit
urea will discontinue process of change become ammonia in fish flesh (Priono
era/., 1986).
Without considering of tamarind concentration, steaming give influence
very significantly to obstetrical discount ammonia of shark flesh result of final
products (P<0,01). The more prolong of time steaming the more reducing of
ammonia so that more to decrease its content in final product. Old influence
of steaming of during 5, 15 and 25 minutes, to content of ammonia in final
product successively is equal to 3,5; 3,3 and 3,1 mg/100g. More and more
time steamed, resulting tying of bunch of ammonia become groggy and finally
broken down later; then evaporated. While NH3yielded from degradation urea
have the nature of dissolve in water hereinafter react by H20 form NH4OH. Its
dissolve in water mean to lessen amount of ammonia in flesh of fish so that
degrade amount of ammonia in final product.
Assess pH flesh of fresh shark equal to 6,9 after soaked in tamarind solution
and steamed and also dried, value of its pH descend and the mean become
5,9. Soaking in tamarind solution of different concentration give influence
very significantly to degradation of pH of final products (p<0,01). The higher
concentration tamarind solution for soaking in different time, give influence
significantly to the degradation of pH of final products (p<0.01).
The higher concentration of tamarind solution for soaking would be reduce
the pH of final products. The difference of concentration of tamarind solution as
5,10 and 15 per cent, yielding pH value of final products equal to 6,4; 5,8 and
5,3 respectively. The degradation of the pH goes together with tamarind solution
penetrating intensity into shark flesh. The higher concentration of tamarind
solution the higher penetrating intensity into flesh, the higher of concentration
of solution to soak and a lot of incoming solution acid into flesh so that cause
to descend assess pH of final product.
Evaluation of Aw of fresh fish equal to 0,934, after processed Aw descend
to become 0,571. The difference of steaming time give significantly influence to
Aw level of final products (p<0,05). The longer the time of steaming the lower Aw
value of final products. A difference time of steaming i.e:(5,15 and 25) minutes,
yielding of Aw equal to: 0,596; 0,568 and 0,550 respectively. Decreasing of it Aw
as an effect of steaming go together obstetrical degradation moisture content,
heated up of flesh and coagulated of protein also result contraction of tissue so
that the moisture inner and inter cell go out, resulting decreasing of moisture
content of fishfleshfollowed by reduction of Aw of final products (Hadiwiyoto,
1993).
Result of sensory test cover aspect of: appearance, texture, aroma or odor
and taste presented in table 2. Value of appearance of final products indicated
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that difference of concentration of tamarind solution, giving significantly influence
to aspect of final products. (p<0,05). The higher concentration of tamarind solution
for soaking, showed the lower value of appearance of final products. Lowest
value evaluation of final products appearance due to the penetration of acid that
existed in the high concentration of tamarind solution for soaking. Concentration
of tamarind solution of: 5, 10 and 15 per cent, resulted value of appearance of
final products i.e: 5.7; 5.5 and 5,3 respectively. The condition as resulted of
penetration of brown pigment of tamarind, so that influenced by appearance
that was evaluated by panelists. The higher the concentration of tamarind
solution for soaking, much more pigment that penetrated into flesh of shark so
that made the lower value of appearance of final products resulted from panelists
evaluation. Meanwhile the difference of steaming time affected significantly
high to the appearance of final products that evaluated by panelists so that
the value of appearance very low (p< 0.01). The longer the time of steaming
the lower of value of appearance that given by panelists to final products,
because of brownish color at the final products. It assumed that tamarind
contain of sugar reduction high enough (about 60.45 per cent of total weight
of pulp) that penetrated into the shark flesh during soaking. It was also due to
a caramel formed brown color i.e. 5-hydroxymethyl-2 furaldehide. Based on
the time of steaming shark flesh as long as: 5,15 and 25 minutes respectively,
resulted the value of appearance i.e: 6.0; 5.6; and 5.0 respectively.
The difference of concentration of tamarind solution for soaking of shark
flesh, affected to significantly high of texture evaluation by panelists (p<0.01).
The higher the concentration of tamarind solution for soaking, the higher value
of texture of shark flesh that evaluated by panelists. It meant that panelists
more like the final products even though the products more fragile. Just only
considering of the concentration of tamarind solution for soaking shark flesh
as much as: 5, 10 and 15 per cent respectively, resulted the value of final
products i.e.: 4.7; 5.5 and 5,6. According to Fawzya (1986), stated that soaking
of shark flesh in acid solution, could reduce of urea content as much as 80
per cent, although texture of flesh became fragile. Retnowati (1990), stated
that tamarind contain of chemical substances such as: tartaric acid, citric acid,
acetic acid and malic acid those able to make membrane cell or flesh become
soft that preferred by consumers.
Jumalllmu dan Teknologi Pangan, Vol. 3, No. 2, 0ktober2005
85
Tables of 2. Results of sensory (appearance, texture, aroma and taste
the salted dried of shark meat.
Treatments
Texture
Appearance
A
B
4,5
5
6,5
4,8
5
5,6
15
4,7
25
5,1
5,3
5,7
5
5,7
5,3
15
10
5,2
5,8
25
5,7
5,0
5
5,7
5,4
15
15
6,0
4,8
25
Note: A: Tamarind Concentration (in %)
B: Old [of] steaming (in minute)
Aroma
Taste
4,7
4,5
5,2
5,2
5,6
5,5
6,3
5,5
5,8
6,4
5,1
5,1
5,0
5,7
5,6
5,4
5,1
6,0
Considering only the long of time steaming affected significantly high to
the value of texture of final products (P<0.01). The longer of steaming time the
higher value of texture of final products. The duration of steaming as long as: 5,
15 and 25 minutes, resulted mean value of texture as level of: 4.9; 5.3 and 5.5
respectively. Analog to the above discussion (that of appearance and texture),
value of aroma (odor) and taste as the same case. The higher concentration of
tamarind solution for soaking of shark flesh, the higher value of odor and taste
and became consumers more like. As the same matter that the difference of
time steaming, the longer the steaming time the higher value of odor and taste
that gave by consumers to the final products. Its meant that the smell and
taste of ammonia of final products much more reduce.
CONCLUSION AND SUGGESTION
The difference of tamarind solution for soaking shark flesh have an effect
on different to content of ammonia that also done pH and results of sensory
test of final product. While the difference time of steaming have an effect on
significantly to value aw, and have an effect on significantly high rate: moisture,
protein, ammonia, assess aspect, texture, odor and taste of final products. Mostly
reduce of ammonia is if flesh soaked in concentration 15 per cent of tamarind
solution. While steaming flesh of during 25 minute assign value highest sensory
(i.e: texture, aroma (odor) and taste. Treatment by soaking in tamarind solution
of 15 per cent and steamed by during 25 minutes, yielding best final products
and taken a fancy to consumers.
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To lessen content ammonia in shark flesh is better by soaking in tamarind
solution of 15per cent, later then cooked at least during 25 minute.
REFERENCES
Fawzya, Y.N. 1986. Pemanfaatan dan upaya mengurangi kadar urea ikan
cucut. Proceeding Seminar teknologi Pertanian. Fakultas pertanian
Universitas Brawijaya, Malang.
Hadiwiyoto, S. 1993. Teknologi Pengolahan Hasil Perikanan. FakultasTeknologi
Pertanian UGM. Penerbit Liberty. Yogyakarta.
Priono, B., Supamo dan S. yayat. 1986. Perlakuan fisis dan khemis untuk mengurangi kandungan urea dalam daging ikan cucut. Laporan Penelitian
Teknologi Perikanan. BPTP. Deptan. Jakarta. Buletin Limbah Pangan,
vol II (1). Januari.
Retnowati, N., mumiyati dan S. Nasran. 1990. Studi penggunaan rempahrempah guna memperpanjang daya awet ikan pindang. Kumpulan hasilhasil penelitian Pasca Panen Perikanan. Badan Litbang Pertanian.
Puslitbangkan. Jakarta.
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