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
41 and fresh. From these words, an assumption can be made that perception of the panelists about green
grass jelly are about the texture, which is chewy and soft; the color, which is green; and the taste, which is tasteless. Furthermore, other panelists tried to write sweet and savoury. It is happened due to
the perception of panelists that always connect green grass jelly with its condiment for serving, such as sugar solution and coconut milk.
Panelists were also asked to rank their priority of sensory parameters when they consume green grass jelly. The whole results can be seen in Appendix 15. The most important priority was
given by the smallest number of rank. From the total of rank for each sensory parameter, the most important sensory parameter is taste since it has the lowest amount of rank. This made the panelists
gave the word of tasteless as the word for their perceptions of green grass jelly. The second priority belongs to the texture of green grass jelly. This made the panelists gave the word of chewy as the first
word for their perceptions of green grass jelly. This priority could be used to help in choosing the chosen concentration of carrageenan.
Hedonic rating test was used to determine the level of consumer preferences for steamed green grass jelly product. The concentrations of carrageenan used in this test were 0, 2.00, 2.25,
and 2.50. 0 carrageenan concentration or treatment without carrageenan was used as a control to see how much the carrageenan addition influence the level of consumer preferences for steamed green
grass jelly. Hedonic rating test results can be seen on Table 9, while the whole results can be seen in Appendix 20.
Table 9. Results of hedonic rating test Carrageenan
concentrations Preference value
Color Aroma
Taste Texture
Overall 2.76
a
2.40
a
2.61
a
1.57
a
2.07
a
2.00 5.13
c
4.20
b
5.43
c
4.80
c
5.26
c
2.25 4.04
b
4.06
b
4.26
b
3.53
b
4.03
b
2.50 3.91
b
4.24
b
4,29
b
3.77
b
4.30
b
The detail of hedonic rating test data from 70 panelists can be seen in Appendix 20. The results variance were then analyzed using SPSS 20 with Duncan further test and can be seen in
Appendix 16. Treatments of carrageenan addition affects the preferences level of color, aroma, taste, texture, and overall of green grass jelly by considering the significance value of each sensory
parameters, which is 0.000 for the preferences of color, aroma, taste, texture, and overall. The whole significant values are less than 5, so the addition of carrageenan significantly affects the preference
level of green grass jelly. Based on the analysis of variance with α = 5, green grass jelly with 2 carrageenan has the
highest level of color preference compared with other treatments, which is equal to 5.13 or somewhat favorable and significantly different from the green grass jelly gel without the addition of carrageenan
which has a level of preference colors only 2.76 or likely slightly preferred. In terms of flavor, green grass jellies with carrageenan concentrations of 2.00, 2.25, and 2.50 are not significantly
different from each other and belongs to the neutral. However, those three concentrations are significantly different to the green grass jelly without the addition of carrageenan which only has
preference for 2.40 or disliked. This is caused by the onset of leaf aroma because of the heating process. No addition of carrageenan causes the leaves aroma wafted over so it is disliked.
42 In terms of taste and overall, green grass jelly with the addition of 2.00 carrageenan has the
highest level of preference, which is slightly like, and significantly different from other treatments. In term of texture, green grass jelly with the addition of 2.00 carrageenan has the highest
level of preference, which was 4.80 or tend to be slightly like, and significantly different from other treatments. The chosen formula from hedonic rating test is green grass jelly with the addition of 2.00
carrageenan since the first and second priorities to choose green grass jelly are taste and texture. The picture of green grass jelly product with the addition of 2.00 carrageenan can be seen in Appendix
17.
G. FU CTIO AL PROPERTIES A ALYSIS
