38 Based on the analysis of the variance with α = 5, all treatments of carrageenan addition
at various concentrations are significantly different from all of the parameters of commercial green grass jelly’s color. This is caused by the absence of heating in the production process of
commercial green grass jelly so there is no reaction that resulted in chlorophyll degradation Gross 1991. Nevertheless, the addition of 2.25 carrageenan has the highest L value than others. This
means that the darkness of green grass jelly with the addition of 2.25 carrageenan is considered as the closest to the darkness of commercial green grass jelly. Green grass jelly with the addition
of carrageenan at other concentrations are capable of forming green grass jelly with darker color than the commercial green grass jelly because their L values possessed lower.
The addition of 2.00 carrageenan is able to produce most negative a value compared with the other carrageenan concentrations. This means that the green grass jelly with the addition
of 2.00 carrageenan has the greenest color, although the value is still significantly different with commercial green grass jelly. For b value, green grass jelly with 1.50 carrageenan is able to
produce the yellow color, which is closest to the commercial green grass jelly, although still significantly different. Overall, the concentrations that produce colors that are not significantly
different from the color of commercial green grass jelly is 2.00. In addition, the concentration of 2.25 is also considered to be close to the color of commercial green grass jelly. This is also
supported by the rupture strength value with the addition of 2.25 carrageenan. Montero and PèrezMateos 2002 pointed out that presence of sodium ions in the gelling process of
carrageenan, both of iota and kappa, will reduce L, a, and b value.
3. Syneresis
In terms of syneresis, the addition of carrageenan concentration of more than 1.25 has been able to make slower rate of syneresis. This can be seen in Figure 19 with syneresis
measurement data can be seen in Appendix 13. By addition of carrageenan concentration of more than 1.25, the lines are becoming increasingly gently sloping shown in curve. Equation of the
line formed for each treatment concentration of carrageenan can be seen on Table 8. Increase of carrageenan concentration is not in line with decrease of syneresis rate. Syneresis measurement
results showed that the addition of 2.50 carrageenan is able to produce slowest syneresis rate compared to other concentrations. Montero and PèrezMateos 2002 pointed out that the addition
of sodium ions on the carrageenan gel will result in increasing water holding capacity. The monovalent ions are bound to the helix of carrageenan and neutralize partially the sulphite bonds,
by this way the double helix are grouping reducing gel syneresis.
39 Figure 19. Syneresis curve of green grass jelly with the addition of carrageenan
Table 8. Syneresis rate equation of green grass jelly with carrageenan addition Treatments
Syneresis Rate Equation Unsteamed Commercial
y = 0.9660x + 11.1530 R² = 0.8759
Carrageenan 0 y = 0.2727x 4.7800
R² = 0.9902 Carrageenan 1.25
y = 0.3873x 6.9433 R² = 0.9973
Carrageenan 1.50 y = 0.1071x 1.4533
R² = 0.9247 Carrageenan 1.75
y = 0.1210x 1.6133 R² = 0.9744
Carrageenan 2.00 y = 0.1144x 0.5000
R² = 0.9596 Carrageenan 2.25
y = 0.1106x 1.0500 R² = 0.9976
Carrageenan 2.50 y = 0.0565x + 0.9133
R² = 0.9844 Carrageenan 2.75
y = 0.0779x + 0.6567 R² = 0.9936
Carrageenan 3.00 y = 0.0713x + 0.7233
R² = 0.9911
4. pH Changes
Observation of changes in the pH of green grass jelly was also conducted. The full results of this observation and its R
2
can be seen in Appendix 14 and briefly presented on Figure 20. Increase of carrageenan concentration makes the pH of green grass jelly decreased. But all of
green grass jellies’ pH by the additions of carrageenans are still about 7.00, which is not acid. The acid condition can lead to chlorophyll degradation Koca et al. 2006. At 0 hour after steaming, all
of green grass jellies’ pH are decreased. This is caused by the release of organic acids from the network due to the heating process Gross 1991. Von Elbe and Schwartz 1996 stated that
heating could initiate decompartmentalization of cellular acids as well as the synthesis of new acids. Decrease in pH after steaming 0 hours in samples with carrageenan are less than without
carrageenan because the hydrocolloid structures are able to bind and adsorb organic acids from the decompartmentalization so that pH reduction is smaller.
5 5
15 25
35 45
55 65
75 85
24 48
72
S y
n er
es is
Time hours
1,25 1,50
1,75 2,00
2,25 2,50
2,75 3,00
Commercial Product
40 The pattern of pH changes by addition of carrageenan is similar with the treatment of
NaHCO
3
on previous stage of research. Start from 24 hours after steaming, all of green grass jellies’ pH are increased in comparison with pH at 0 hour after steaming. It might be happened due
to the buffering effects of NaHCO
3
. Above 70 °C, sodium bicarbonate gradually decomposes into sodium carbonate, water, and carbon dioxide, resulting the increasing pH Lakhanisky 2002.
Furthermore, NaHCO
3
which has been ionized to be Na
+
and HCO
3
in the water is transformed to be H
2
CO
3
and OH reversibly. Release of Na
+
will raise the pH. Furthermore, as the concentration of HCO
3
increased, reaction equilibrium is shifted to the right side, increasing the production of OH
. It shall increase the pH. Until at certain concentration, OH present will shift the reaction equilibrium back to the left side, increasing the production of HCO
3
, decreasing the pH. The existence of carrageenan will affect the concentration of free water which can react with HCO
3
. The pattern of free water concentration can not be ascertained with the addition of carrageenan
concentration. The most effective buffering effect of NaHCO
3
was on the concentration of 2 carrageenan since it has the most not fluctuative pH changes with the largest R
2
value, 0.4579.
Figure 20. Graphs of pH changes by carrageenan addition treatments Based on the texture and pH changes, the chosen carrageenan concentration was 2.00. This
was caused by the insignificantly different texture to commercial grass jelly. In addition, the color of green grass jelly which is the closest to commercial green grass jelly gel is green grass jelly with the
addition of 2.00 and 2.25 carrageenan. Syneresis analysis results for both concentrations are also quite good as the curves formed were ramp. The third chosen concentration was 2.50 because it has
the most ramp syneresis curve compared to other concentrations. In addition, the rupture strength value is also not significantly different with commercial green grass jelly. The three chosen concentrations
were then analyzed on the level of sensory acceptance to get one chosen concentration.
F. SE SORY EVALUATIO
Before hedonic rating test conducted to determine consumer preferences, panelists asked to write down 5 simple words that are associated with green grass jelly based on their perception. The
whole results can be seen in Appendix 15. The top 5 words collected are chewy, green, tasteless, soft, 6,4
6,6 6,8
7 7,2
7,4 7,6
7,8 8
8,2
Before steaming
0 hour after steaming
24 hours after
steaming 48 hours
after steaming
72 hours after
steaming
p H
Treatments
1.25 1.50
1.75 2.00
2.25 2.50
2.75 3.00
