ISSN 2086-5953 The objective of this work is to chitosan
coating effect on noodle chemical, textural properties, sensorial acceptance and deterioration
delay related to chitosan antimicrobial activity. Furthermore, this research may provide basic
information
to develop
chitosan as
food biopreservatives.
2 MATERIAL AND METHOD
2.1 Material
Chitosan was made from shrimp shells by chemical processes, obtained from The Indonesian
Institute of Sciences LIPI. Noodle was made according to the method used by noodle local
producer in Yogyakarta, using wheat flour and food grade additives. All chemicals used were analytical
grade.
2.2 Preliminary
This process was conducted to determine noodle boiling time to obtain noodle with 55 as
standard moisture
content, acetic
acid concentration, and ratio between noodle and
dipping solution that sensorially accepted. To measure chitosan properties, proximat content,
solution viscosity, and deacetylation degree were also analyzed according to each standard analysis
[12].
2.3 Sample preparation
The experimental samples were prepared according to the basic formulation. They were
made from hard wheat flour and mixing with 35 water, 1 salt and 2 alkaline solution. The flour
was formed into dough sheets before cutting. The string-shaped noodle was then dipped into boiled
water for 1 minute.
Dipping solution were made by dissolving chitosan powder into 0.5 acetic acid in
concentration of 0, 0.5, 1, and 1.5 wv, using sterilized beaker glass. Samples were divided
and dipped 2 minutes into each solution in ratio 1:6 gml. After drained, samples were placed inside
sterile sealed polyethylene bags for room temperature incubation, prepared for triplicate
samplings, every 10 hours from 0 to 40 hours. Samples weight differences before and after
dipping were counted as retained chitosan on samples surface.
2.4 Chemical, physical and sensorial
properties analysis
Right after dipping process, samples properties were determined for pH using pH meter
and also for moisture, protein, fat and ash content according to AOAC 2000. Noodle physical
analysis as conducted in quantitative and qualitative measurement. The textural qualities of the cooked
noodles,
in strength
and break
distance extensibility, were measured on a Lloyd Texture
Analyser in triplicate at three random locations of noodle string. The noodles were tested individually.
The F
max
values recorded for freshly made sample and 45 hours incubated sample. Physical changes
during incubation were also observed. Samples were evaluated for sensory acceptability by 20
trained panelists. Scoring method in scale 1-10 1=unrecognizable, 10=extremely recognizable
was used to analyze whether chitosan application was recognizable in term of noodle taste and aroma.
While hedonic test in scale 1-7 1=dislike extremely, 7=like extremely was used to analyze
samples acceptability. The effect of cleansing after dipping was also sensorial analyzed.
2.5 Chitosan antimicrobial analysis
Total viable cells of samples were counted as colony forming unit per volume CFUml using
most probable number method in spread plate [13]. Samples from 0, 10, 20, 30, and 40 hours
incubation were mixed with sterile peptone water 1:9 gml, homogenized, and inoculated in
Nutrient Agar media, then incubated for 24 hours.
2.6 Statistical analysis
The values reported are the mean of these independent experiments. Differences between
variables were tested for significance by 1-way analysis of variance ANOVA. Duncans Multiple
Range Test was used to detect mean differences. Differences at P 0.05 were considered to be
statistically significant.
3 RESULTS AND DISCUSSION
3.1 Chitosan properties and noodle
dipping
The properties of chitosan used in this research as shown in Table 1 confirmed that
chitosan used was prepared according to standard as food grade chitosan [12], with 98.47 degree of
deacetylation above standard of 70 and
ISSN 2086-5953 viscosity of 860.02 centiPoise between 200-3000
centiPoise standard. But retained chitosan amount were very low
on all samples indicating that dipping method could not guarantee high amount of chitosan retained on
samples surface.
Table 1. Chitosan properties compared to standard
Properties Value
Standard
1
Moisture Total N db
Viscosity
2
cP Degree of
deacetylation
3
9,37 7,39
860,02 98,47
2-10 7-8,4
200-3000 70
3.2 Chemical, physical and sensorial
properties
The results
of noodle
properties measurements after dipped into chitosan solution
are shown in Table 2. Acidity of dipping solutions slightly decreases resulted in higher pH of dipped
noodle while retained chitosan on noodle surface increase
with the
increase of
chitosan concentration. The presence of retained chitosan
also increase acetic acid retained on noodle surface resulting higher acidity of dipped noodle than both
non-dipped and non-chitosan samples. In the other hand, dipped samples acidity slightly increase,
indicating the presence of chitosan able to reduce acidity. The increase of chitosan concentration
significantly increase the moisture content α: 0.05 while fat content decreased in concentrations
dependent manner. The oil layer was diminished in the drain process due to interaction between
positively charged chitosan able the negatively charged free fatty acids. Protein amount was
significantly increase after dipping but did not significantly
influenced by
concentration differences due to the low amount of retained
chitosan.
Table 3. Noodle physical properties
Sample F
max 1
Strain at
F
max 2
0 hour 45
hours hour
45 hours Without dipping
Acetic acid 0,5 0,5
1 1,5
2,34
b
1,84
a
1,83
a
1,88
a
2,13
ab
0,80
b
0,82
b
0,65
a
0,87
b
0,90
b
57,51
a
53,71
a
55,45
a
55,64
a
54,44
a
21,42
a
20,29
a
20,93
a
30,53
a
28,26
a
Results shown in Table 3 confirmed that the textural properties of noodle, irrespective of
chitosan concentrations, were decreased after 45 hours of room temperature incubation. Generally,
dipped samples were not significantly different with those non-dipped samples due to the low
amount of retained chitosan. But dipping into 1 chitosan solution significantly increase sample
stextural endurance after 45 hours incubation compare to the control. Physical qualitative
observation also confirmed that samples dipped in chitosan solution have better physical appearance
due to deterioration inhibition.
Table 4. Noodle Sensorial Properties
Sam ple
Properties Taste
Aroma Color
Texture Overall
A B
B‘ C
C‘ D
D‘ E
E‘ 4,72
a
4,64
a
4,96
a
4,72
a
4,36
a
4,40
a
4,28
a
4,52
a
4,44
a
4,48
bc
3,88
a
4,64
c
3,72
ab
4,56
bc
3,44
a
4,08
abc
4,48
bc
4,32
bc
3,76
a
4,76
bc
5,24
c
4,92
c
4,12
ab
5,16
c
5,00
c
4,56
bc
4,52
bc
3,68
a
4,76
b
4,92
b
5,00
b
4,88
b
4,72
b
5,16
b
4,52
b
4,48
b
4,32
a
4,68
a
5,00
a
4,88
a
4,72
a
4,56
a
4,84
a
4,60
a
4,56
a
Table 2. Noodle properties after dipped into chitosan solution
Treatments
1
Solution pH
Retained chitosan
2
mg10g Noodle pH
after dipping
Moisture wb
Total Nitrogen
db Protein
db Fat
db Without dipping
Acetic acid 0,5 Chitosan solution 0,5
Chitosan solution 1 Chitosan solution 1,5
- 3,6
3,7 3,7
3,8 -
- 0,204
0,503 1,808
6,5 6,1
5,1 5,2
5,5 54,99
d
60,30
e
45,80
a
49,60
b
53,40
c
1,82
b
2,05
b
1,33
a
1,46
a
1,58
a
11,40
b
12,82
b
8,30
a
9,14
a
9,86
a
6,88
d
4,05
c
2,67
c
1,71
b
1,30
a 1
Standard according to Muzarelli 1997
2
Analysis using 1 chitosan solution in 1 acetic acid
A : Without dipping B: Acetic acid 0,5
C: Chitosan solution 0,5 D: Chitosan solution 1
E: Chitosan solution 1,5
1
For dipped samples, 10 grams of noodle dipped into 60 ml chitosan solution. Controls are non-dipped noodle and acetic acid dipped noodle
2
Values reported are the mean of triplicate independent experiment per 100 gram samples
ISSN 2086-5953
0.00 1.00
2.00 3.00
4.00 5.00
6.00 7.00
8.00 9.00
10 20
30 40
jam pengamatan
L o
g C
F U
m l
A B
C D
E
Figure 1. Microbial growth in noodle during room temperature incubation
From sensorial analysis shown in Table 4, the results confirmed that chitosan coating were
generally recognized and received by consumers with the highest hedonic values went to the wet
noodle dipped in 0.5 chitosan solution. Noodle cleansing after dipping generally had higher
hedonic values with the highest went to the 1 chitosan.
3.3 Chitosan antimicrobial properties
