EFFECTS OF VARIOUS DRYING METHODS ON THE QUALITY OF SHARK DENDENG

EFFECTS OF VARIOUS DRYING METHODS ON THE QUALITY
OF SHARK DENDENG

Nurul Huda, Ruzita Ahmad and Ratna Sari Dewi

Food Technology Divison, School of Industrial Technology
Universiti Sains Malaysia, Minden, 11800, Malaysia
nrlhd@usm.my



Abstract

Dendeng is sliced dried meat, normally made from beef. However, some fish
species also have the potential to be processed into dendeng. The aim of this study was to
identify the quality (proximate, color and sensory) of dendeng made from shark
(Chiloscyllium sp) flesh. Three drying methods were used in this study and they were sun
drying, oven drying (60°C) and oven vacuum drying (60°C). Before drying, the slices
with dimensions of 4cm x 12cm x 3mm, were soaked in a mixture of 20% sugar, 4% salt,
5% tamarind, 1.5% coriander, 0.5% ginger, 1.0% garlic, 1.5% onion, and 2.5% galangal
for 12 hours. The drying was carried out until the moisture content reached 23-25%.
Proximate analysis showed that there was no significant differences among the three
samples, except for the fat content of of sun dried sample, which was significantly lower
than the others. The range of moisture, protein, fat, ash, and carbohydrate content among
the samples were 24.5-25.2%, 48.0-50.6%, 1.9-2.4%, 13.8-14.5%, 33.1-35.2%
respectively. Colour analysis showed that there were significant differences among the
samples. The L, a and b values of the samples were about 48.66-54.26, 8.36-9.47, and
26.72- 27.34 respectively. Lightness ( L- values ) recorded were, 54.26 for sun drying
followed by 52.66 for vacuum drying and 48.06 for oven drying. There were no
significant differences for sensory analysis (n=50), using a 7-point hedonic scale ( 1
equals dislike very much and 7 equals like very much ) in terms of colour ( 4.46 -
5.68 ), odour ( 5.20 – 5.48 ), taste ( 4.72 – 5.00 ), texture ( 4.20 – 4.94 ), and overall
acceptability ( 4.74 -5.0 ). However, shark dendeng using oven drying was rated highest
among the samples.

Keywords : Drying processes, shark flesh, underutilized fish.


1. Introduction
Among the several methods of long term preservation of fish, drying is perhaps
the simplest method as it does not require sophisticated equipment or highly skilled
workers. Dendeng is a type of preserved meat product traditionally in Indonesia by
adding sugar, salt and spices into thinly sliced meat which were then dried. However,
some fish species also have the potential to be processed into dendeng, for example
mackerel, sardine, shark, etc ( Wibowo, 1995). This dried product is similar to Biltong
in south Africa, meat jerky in North America, Carne de Soue in South America,
Pemmican in North America, Charqui in Brazil and Sou song in China (Leistner, 1987 ).

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Dendeng can be dried using sun drying or using mechanical dryer. During the
draining process, texture, color, nutritional values and aroma also changed. Decreasing
rate of water loss can increase protein content, carbohydrate, mineral and fat, but
generally, vitamin were destroyed or decreased (Fachrudin, 1997).
Utilization of Elasmobranch fish such as shark is still limited. The amount of
catches in Malaysia continues to increase every year from 13678 ton in 1989 to 25195
ton in 2001 (Ali et al, 2004). Therefore, making fish dendeng gives added value to the
fish.

2. Material and Methods
Dendeng Preparation
Shark fish (Chiloscyllium sp). were bought from the local fish market and brought
to the processing laboratory of Food Technology Division, Universiti Sains Malaysia.
Processing of dendeng were carried out using the method of Nasran (1993). Spice
mixture for soaking the fish flesh was prepared and contained brown sugar (20%), salt
(5%), tamarind (4%), coriander (1,5%), root of galangal (2.5%), ginger (0,5%), garlic
(1,0%), and onion (1,0%). Dendeng was dried using three different methods, which were,
sun drying, oven drying (60°C) and oven vacuum drying (60°C).

Shark flesh


Sliced (4cm x 12cm x 3mm)

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Immersed in salt solution for 10 minute


Soaked in spice mixture for 12 hours at chilling temperature





Sun drying Oven drying (60ºC) Vacuum drying (60ºC)


Shark Dendeng

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Proximate Composition
The macronutrient of Shark dendeng was determined according to AOAC
methods (1990). The macronutrients analyzed were moisture, protein, fat, ash, and
carbohydrate.

Colour Measurement
Colour Measurement was made using a colorimeter (Minolta CM 3500m, Japan).
The colour reading includes lightness (L), redness (a*), and yellowness (b*). The
equipment was standardized with a white colour standard.

Sensory Evaluation
Panels of 50 student Universiti Sains Malaysia participated in the study. A 7-
points hedonic scale method (7 : Like very much and 1 : Dislike very much) was used to
evaluate the colour, odour, taste, texture – bite and overall acceptability.

Statistical Analysis

Data were analysed statistically by Analysis of Variance ( ANOVA ) and the significance
between the means was determined by using Duncans Multiple Range Test at p=0.05. For
the sensory data, the significance between the means was determined by the Tukey test.

3. Results and Discussion

Fat content of fresh shark flesh was about 1.56%. Fish species with low levels of
fat are suitable to be processed. Fat content increase, while water content decrease
correspondingly. Heating undoubtedly causes oxidation of lipid in fish (Aitken and
Connell, 1979). There were no differences (p>0.05) for proximate analysis except for the
fat content ( Table 1 ). Lowest fat content was for sample dried in sun drying. Sun drying
causes considerable loss of polyunsaturated fatty acids (Rao and Bandyopadhyay, 1983).
Ikegami et al (1971) concluded that lipid oxidation and protein denaturation resulted in a
decrease in nutritive value.

Table 1. Proximate composition of shark dendeng

sample Moisture
Protein
Fat
Ash
Carbohydrate
(% db)
(% db)
(% db)
(% db)
(% db)
Sun
drying
24.46±0.60 50.58±1.66 1.90±0.09 14.47±0.45 33.05±1.66
Oven
drying
25.18±0.59 49.96±3.86 2.41±0.25 13.43±0.77 34.19±2.99
Vacuum
drying 25.23±0.04 47.96±4.82 2.40±0.18 14.48±0.16 35.16±5.06

The colour properties of Shark dendeng is shown in Table 2. There were
significant differences (p>0.05) in colour (L, a* and b*). It was observed that different
drying methods affected the lightness, redness and yellowness of the samples. In some

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places (e.g. Hong Kong) the dark colour and rancid odour of cured fish is a sign of
quality (Bligh et al, 1988). The Maillard reaction, in combination with oxypolimerisation
of unsaturated fish oils, were responsible for the darkening, toughening, and the
unpalatable, bitter flavour associated with lengthy drying process and storage of
dehydrated fish (Cutting, 1962). Seasoning, like sugar, tamarind, coriander and roots of
galangal also influenced the colour of dendeng.
Table 2. Colour properties of Shark dendeng
Sample
Lightness (L)
Redness (a*)
Yellowness (b*)
Sun drying
36.34±0.28
3.31±0.61
9.36±0.93
Oven
drying
39.36±0.26 8.33±0.62 20.44±0.82
Vacuum
drying 42.58±0.22 7.45±0.17 17.42±2.60

Table 3 shows the sensory evaluation data of shark dendeng. There was no
significant difference (p>0.05) noted on the colour, odour, taste, texture-bite, and overall
acceptability of Shark dendeng. The panelist failed to detect any differences among the
Shark dendeng. The average score of sensory evaluation is close to 5 which mean that
Shark dendeng is accepted by Malaysian panelist. Bligh et al, (1988) concluded that the
major effect of lipid degradation is development of aesthetically unappealing odours and
flavours while the effect of oxidative rancidity on the nutritive quality of fish, especially
in terms of protein availability, is debatable.

Table 3. Mean sensory scores of Shark dendeng
Overall
sample Colour
Odour
Taste
Texture-bite
acceptance
Sun
drying
4.46±1.63 5.20±1.41 4.72±1.37 4.20±1.59 4.74±1.47
Oven
drying
5.70±0.91 5.48±1.30 5.06±1.41 4.84±1.45 5.10±1.22
Vacuum
drying 5.42±0.99 5.22±1.23 4.78±1.56 4.94±1.57 5.02±1.30

4. Conclusion
The result showed that Shark flesh has the potential to be produced as dendeng.
Here, we demonstrated that different drying methods affect colour but not the proximate
composition.

Acknowledgements
This project was supported by the short-term grant from Universiti Sains
Malaysia 304/PTEKIND/636055.

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