IV. RESULT DAN DISCUSSION
4.1 Result
Total microorganism was changed during PKM fermentation Table 3. Total aerobic bacteria corresponded approximately to the sum of total bacteria
from TSA media and from MRS media. The highest number of aerobic bacteria, 17.2 log
10
CFUg, was found at 24 hours of fermentation. The highest total bacteria from TSA media, 9.6 log
10
CFUg, was found at 24 hour and decreased later happened until 7.9 log
10
CFUg at the end of the fermentation process; while lactic acid bacteria, isolated from MRS media, were most found, 8.6 log
10
CFUg, at 36 hours of fermentation. Total anaerobic bacteria corresponded approximately
to the sum of total bacteria from TSA media anaerobically incubated and from RCA media. Total anaerobic bacteria were not found until 12 hours of
fermentation and the highest number, 17.3 log
10
CFUg, were found at 72 hours. No fungi were found before 96 hours of fermentation.
Table 3. Total bacteria and fungi log
10
Time of sampling
hour
CFUg during PKM fermentation
Aerobic bacteria Anaerobic bacteria
Total bacteria
Total fungi
5
TSA MRS
1 2
RCA
3
TSAan
4
7.5 7.5
12 9.1
3.0 7.3
19.4 24
9.6 7.6
7.7 8.3
33.2 36
8.5 8.6
7.8 8.7
33.7 48
8.8 8.5
7.4 8.7
33.4 60
8.7 8.3
7.7 8.5
33.2 72
8.4 7.6
8.7 8.6
33.3 84
8.5 7.1
8.0 8.2
31.8 96
7.9 6.7
8.1 7.9
30.6 5.5
108 7.6
6.8 7.9
7.9 30.2
6.4 120
7.8 6.7
8.0 8.0
30.5 6.3
132 7.9
5.7 8.0
8.1 29.8
6.0 144
7.6 6.6
7.7 7.9
29.8 6.6
156 8.1
5.9 7.5
8.0 29.5
6.2 168
7.9 5.9
8.0 8.0
29.8 6.4
1
Total bacteria from media TSA Trypticase Soy Agar incubated in aerobic condition;
2
Total bacteria from MRS media De Man, Rogosa and Sharpe;
3
Total bacteria from media RCA
Reinforce Clostridial Agar;
4
Total bacteria from media TSA Trypticase Soy Agar incubated in anaerobic condition;
5
During fermentation, 266 types of bacteria were successfully isolated. From those isolates, 179 were gram + bacteria and 87 gram
− bacteria. The number of isolates on each sampling and their respective characterization could be
seen on Table 4.
Total fungi from media SGA Sabouraud Glucose Agar.
Tabel 4. The number of bacteria on each sampling and their respective characterization
Time of sampling hour
Gram stain number of isolate +
− Total isolate
cocci bacilli
Cocci bacilli
1 3
4 12
1 4
4 7
16 24
3 5
5 13
36 6
14 3
1 24
48 2
12 1
5 20
60 4
9 1
3 17
72 14
1 5
20 84
3 12
3 2
20 96
1 9
1 3
14 108
12 6
18 120
16 1
3 20
132 4
7 6
17 144
14 6
6 26
156 9
7 16
168 17
4 21
Total 24
155 24
63 266
The results of physio-chemical properties during fermentation of PKM are shown in Table 5. During the fermentation process, pH decrease piercingly from
4.56 to 4.28 after 48 hours of fermentation and then decreased until 3.98 at the end of fermentation. The decrease of pH was followed by the increase of total
acid in the fermentation process. Total acid increase from 0.19 to 0.22 µMolmL after 48 hours of fermentation. Table 5 also shows that at the most of time,
temperature of fermentation inside drum fluctuates according to the environmental temperature outside drum.
Table 5. pH, total acid µMolmL, and temperature fermentation
C changed during PKM Time of
sampling hour pH
Total acid µMolmL
Temperature C
Inside drum Outside drum
4.56 0.19
28.65 25.24
12 4.97
0.17 29.38
23.86 24
5.06 0.16
29.38 23.17
36 4.63
0.20 29.02
25.07 48
4.28 0.22
28.28 23.34
60 4.17
0.28 29.75
25.94 72
4.15 0.29
27.38 23.68
84 3.98
0.29 28.65
23.17 96
3.97 0.30
26.50 23.34
108 3.95
0.32 28.28
21.84 120
3.95 0.31
25.97 23.01
132 3.96
0.30 28.83
25.07 144
3.97 0.30
26.68 24.55
156 4.00
0.27 29.94
25.59 168
3.98 0.28
27.38 23.86
Based on the fluctuation of fermentation temperature Table 5 and the total microorganism Table 3, were observed the environmental temperature does
not affect the temperature of fermentation when rise in organism activity. These phenomenons were observed around the first 36 hours and at 96 hours
fermentation. Two temperature rises occurred. Once when there was a rise in bacterial activities and another when there was a rise in fungal and bacterial
activities. Whenever the organism activities of both bacteria and fungi become stable, the temperature of fermentation returns to fluctuate according to the
environmental temperature. The temperature of fermentation mentioned disparity in temperature fluctuation confirms that the rise of microbial activities generated
enough heat to counteract the temperature fluctuation occurring environmental temperature Figure 11.
Figure 11. Relationship between temperature fermentation and microbial activity Percentage fiber and protein of PKM changed during the fermentation
process Table 6. The lignin content of PKM decreased drastically 51.34 after 168 hours fermentation. Hemicelluloses and cellulose content of PKM decreased
10.79 and 10.77, respectively during fermentation process. The protein content of PKM only increased 4.79 after 168 hours of fermentation.
Table 6. Hemicellulose, cellulose, lignin in dry basis and crude protein in dry basis content of PKM during fermentation
Component of PKM Time of sampling hours
36 168m
Water content 69.17
±0.25 71.68±0.39
74.82 ±0.36
NDF 22.57
20.96 17.69
ADF 14.84
12.82 10.79
Lignin 6.02
3.21 2.93
Hemicelullose 7.73
8.14 6.90
Celullose 8.81
9.61 7.86
Crude Protein 17.53
±0.24 18.37
±0.31
average value ±SD; NDF = Neutral Detergent Fiber; ADF = Acid Detergent Fiber
The concentration of glucose and fructose decrease keep face with increasing time of fermentation. However, the concentration of mannose increase
drastically from 1.739 to 3.297 gL after 36 hours of fermentation then decrease along the time of fermentation Table 7.
Table 7. Concentration of soluble sugar during PKM fermentation Time of
sampling hour D-glucose
gL D-fructose
gL D-mannose
gL 0.793
±0.18 0.955
±0.08 1.739
±0.01 36
0.063 ±0.06
0.135 ±0.01
3.297 ±0.13
48 0.034
±0.00 0.080
±0.02 0.065
±0.03 72
0.018 ±0.01
0.014 ±0.00
0.146 ±0.00
96 0.007
±0.00 0.044
±0.01 0.123
±0.02 120
0.012 ±0.02
0.014 ±0.00
0.142 ±0.00
Average value ±SD
Volatile organic acid concentrations along the process of fermentation could be seen in Table 8. During fermentation, acetic acid dominates the
composition of volatile organic acids. After 72 hours the concentration of acetic acid raised, up to 87.89 mMol, compared to the acid’s concentration on the 36
hour. Table 8. Concentration of volatile organic acid mMol during PKM fermentation
Type of volatile organic acid
mMol Time of sampling hour
36 72
168 Acetic acid
67.17 31.89
87.89 55.41
Propionic acid 2.97
10.51 2.95
2.37 Iso butyric acid
0.38 0.25
0.17 0.23
n-Butyric acid 1.68
0.62 0.37
0.42 Iso valeric acid
0.33 0.22
0.20 0.18
n-Valeric acid 0.00
0.00 0.00
0.00
4.2. Discussion
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