29
1. Taste
Taste was analysed in order to ensure that addition of NaHCO
3
does not affect the taste of green grass jelly to be bitter. It was conducted by 10 untrained panelists. Taste of green grass
jelly without the addition of sodium bicarbonate is slightly tasteless. Taste of green grass jelly with the addition of 0.125 NaHCO
3
is tasteless, while the taste of green grass jelly with the addition of 0.583 NaHCO
3
is significantly bitter. In terms of taste, the chosen treatments were 0 and 0.125 of NaHCO
3
concentrations since green grass jelly has bitter taste at the NaHCO
3
concentration of 0.583.
2. Color
Color of green grass jelly was observed using Minolta Chromameter CR 200. The results of this measurement were in the form of Hunter L, a, and b notation. The resume of measurement
results before and after steaming can be seen on Table 4, while the picture and whole results are presented in Appendix 3a and Appendix 3b. In the terms of treatment before steaming, addition of
0.125 NaHCO
3
results in the greenest color since it has the most negative a value. Furthermore, this treatment also has the highest value of L and b, which means lightest and yellowest green
grass jelly. Addition of NaHCO
3
results in more green color since the gel color without the addition of NaHCO
3
has positive a value, less green color. In the terms of treatments after steaming, without the addition of NaHCO
3
, the resulting gel is less green because the a value is still positive. The addition of 0.125 NaHCO
3
results in more green color than 0.583 because of the addition of 0.125 NaHCO
3
results more negative a value. Gel color with addition of 0.125 NaHCO
3
is also brighter because of highest L value. Steaming will lead to chlorophyll degradation reaction to form a brownish pheophytin Gross
1991. Von Elbe and Schwartz 1996 pointed out that the first change observed when the chlorophyll molecule is exposed to heat is isomerization. Chlorophyll isomers are formed by
inversion of the C10 carbomethoxy group. Furthermore, the magnesium atom in chlorophyll is easily displaced by two hydrogen ions because the porphyrin ring is opened, resulting in the
formation of olivebrown pheophytin Yamauchi and Watada 1991. The addition of sodium ions can attribute to the electrostatic shielding effect of the salts.
It was proposed that neutralize the negative charge on the surface of fatty acids and protein in the chloroplast membranes, thereby reducing the attractiveness of hydrogen ions to the surface of the
membrane Nakatani et al. 1979 in Von Elbe and Schwartz 1996. The best concentration of NaHCO
3
that can be used for green grass jelly is 0.125 since the higher concentration 0.583 will change the chlorophyll charge to be too positive so that it will disturb the ion equilibrium of
chlorophyll and can change its color to be less green. This is in accordance with Koca et al. 2006 that much higher temperatures accelerate green colour losses at higher pH conditions.
30 Table 4. Results of green grass jelly’s color measurement
[NaHCO
3
] Before Steaming
After Steaming Changes
L a
b L
a b
L a
b 26.60
a
0.26
c
9.77
a
26.98
a
1.32
c
8.37
a
0.38 1.06
1.40 0.125
27.89
a
1.23
a
10.87
a
30.21
c
1.47
a
12.66
c
2.32 0.24
1.79 0.583
27.30
a
0.54
b
10.52
a
27.74
b
0.30
b
9.30
b
0.44 0.24
1.22 Note: significant changes p0.05
The results of color measurement variance before and after steaming were analyzed using SPSS 20 with further test of Duncan, in separate analysis. These results can be seen in Appendix 4
and Appendix 5. Addition of NaHCO
3
treatments affect the value of L, a, and b to that could be seen from the significant values of a value before steaming and L, a, and b after steaming, i.e.
0.000 which are less than 5, so the addition of NaHCO
3
treatments significantly affect the color of green grass jelly. On the other hand, addition of NaHCO
3
doesn’t affect color parameters of L and b value before steaming since the significant values are 0.146 for L value and 0.713 for b
value. Duncan further test of L, a, and b value indicate that the addition of 0.125 NaHCO
3
is significantly different to the other treatments both before and after steaming. Before steaming, it
has insignificantly lightest, significantly greenest, and insignificantly yellowest color than another treatments. Meanwhile, it has significantly lightest, significantly greenest, and significantly
yellowest color than another treatments after steaming. Furthermore, the results of color measurement variance both before and after steaming
were analyzed using ttest to investigate the significant changes of each treatment of NaHCO
3
addition because of steaming treatment. The ttest results are presented in Appendix 6. Steaming treatment could increase the a value of green grass jelly without addition of NaHCO
3
significantly, which means less green color significantly
.
It also increases L and b value of green grass jelly with addition of 0.125 NaHCO
3
significantly, which means lighter and yellower color significantly. But the a value is decreased insignificantly, which means greener color insignificantly
.
Moreover, steaming treatment could not affect the all color parameters of green grass jelly with addition of
0.583 NaHCO
3
significantly. It is happened due to highest pH reached can reduce the attractiveness of hydrogen ions from the organic acids to the membrane surface of chlorophyll
effectively Nakatani et al. 1979 in Von Elbe and Schwartz 1996.
3. Syneresis Rate
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