32 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. It can be seen from the pH at 72 hours after steaming. For the treatment without addition of NaHCO
3
, increasing pH was happened due to the partial degradation and βelimination of carboxyl groups in the polysaccharide chains which
also impact to the gel texture. Release of magnesium ion form chlorophyll structures also leads to the increase of pH Saris et al. 2000.
NaHCO
3
addition at the concentrations of 0.125 and 0.583 produced green grass jelly with less fluctuative pH change than without addition of NaHCO
3
. It can be seen from R
2
value at the graph. The largest R
2
value belongs to the NaHCO
3
concentration of 0.583. But, addition of 0.583 NaHCO
3
makes the taste of green grass jelly to bitter. Furthermore, pH of green grass jelly by addition of 0.125 NaHCO
3
after 3 days of storage is not so different with pH of that sample before steaming. In terms of pH changes, the chosen treatment was 0.125 of NaHCO
3
concentration.
Figure 18. Graphs of pH changes by NaHCO
3
addition treatments Based on the taste parameter, the chosen NaHCO
3
concentration were 0 and 0.125 since it could not affect green grass jellies’ taste to be bitter. Based on the color parameter, the chosen
NaHCO
3
concentration was 0.125 because of its lightest, greenest, and yellowest color. This concentration also has the lowest syneresis rate. Based on the pH changes, the most linear one belongs
to the NaHCO
3
concentration of 0.583. But this concentration could not be used since it affects to the bitter taste. From the overall parameters, the chosen concentration of NaHCO
3
was 0.125. This concentration would then be used for the all green grass jelly formula with steaming treatment.
D. DETERMI ATIO OF
HYDROCOLLOID TYPE
A D CaCO
3
CO CE TRATIO
In this stage, extracts of green grass leaves were combined with hydrocolloids such as alginate, low methoxyl pectin, mixture of alginate and low methoxyl pectin 1:1, and mixture of
kappa and iota carrageenan 1:1, without steaming treatment. They were also combined with 0.125 NaHCO
3
as the chosen concentration from the previous stage. They were observed on their color R² = 0.1278
R² = 0.1543 R² = 0.2505
5 6
7 8
9 10
Before steaming
0 hour after steaming
24 hours after steaming
48 hours after steaming
72 hours after steaming
p H
Treatment
0.125 0.583
appearance and gelling ca studies had been conducted
Camus 2000 and Rustan mixed with hydrocolloid ty
process. The best gel stren hydrocolloid LMP: Alginat
Table 5. R Hydrocolloids
Alginate
Low Methoxyl Pectin LMP
Mixture of alginate and Low
Methoxyl Pectin LMP 1:1
Mixture of kappa and iota
carrageenan 1:1 ng capability. Results of this stage is briefly presented o
ducted to find a suitable type of hydrocolloid. Previous r ustanti 2000 have succeeded to create the best formula
loid type of Low Methoxyl Pectin LMP and Alginate, w l strength generated by formula of 2 green grass extract
lginate = 1:1 as much as 1.75 and soaking in a solution of ble 5. Results of several hydrocolloid types and CaCO
3
addi Without CaCO
3
With CaCO
3
33 nted on Table 5. Literature
ious research conducted by ormula of green grass jelly
ate, with thermal treatment extract with the addition of
tion of 4 CaCl
2
. addition
Description Without and with
addition of
CaCO
3
, gel was not
form. Addition
of CaCO
3
caused gel color to be
pale. Addition
of CaCO
3
caused not
only gel
formation, but
also color change to be pale.
Addition of
CaCO
3
caused not
only gel
formation, but
also color change to be pale and
whitish. Without addition
of CaCO3, gel was formed and
color was
normal. Addition of
CaCO3 caused color to
be pale.
34 Hydrocolloid gelling component contained in the green grass jelly, which is categorized as
Low Methoxy Pectin Artha 2001, has similarities with the LMP and Alginate to be added, which require calcium ions to form a gel and use the egg box model gelling mechanism. Extracts of green
grass leaves, which were combined with hydrocolloids such as alginate, and mixture of pectin and alginate, were not able to form good structure of green grass jelly. This is caused by the difference in
gelling mechanism used by previous studies, in which gelling mechanism of alginate used was in the form of diffusion setting, characterized by gelling mechanism of cross linking ion Ca
2+
diffuse from the media into the alginate solution. In this study, the gelling mechanism used was the internal setting,
characterized by Ca
2+
ions are released in a controlled manner from a particular source of calcium in alginate solution. Diffusion setting can not be used in this study because it is only suitable to form a
gel in the form of small droplets. Furthermore, green grass extract combined with low methoxyl pectin could form good gel texture only if there was CaCO
3
addition. However, the addition of CaCO
3
caused the poor color of green grass jelly. Color of green grass jelly tended to be unevenly pale because
CaCO
3
is not easily soluble in water. Therefore, hydrocolloids either in the form of pectin, alginate, or a mixture of pectin and alginate could not be used in this study.
Hydrocolloid finally used in this study was carrageenan. Carrageenan used in this study was a mixture of kappa carrageenan and iota carrageenan 1:1. Kappacarrageenan is capable of forming a gel
with good gel strength and more powerful than the iotacarrageenan, but the structure of the gel is too strong compared to the green grass jelly. This is caused by the content of sulfate that existed higher at
iota, where high sulfate contents cause rupture of anhydro3,6Dgalactose bond so the gel strength decreases Pebrianata 2005. In addition, kappacarrageenan is only able to dissolve in water with high
temperature. Kappa carrageenan dissolved into water with room temperature will enlarge to form coarse distribution that requires heating to 70°C to be easily dissolved. Iota carrageenan gel has a
structure that is not as strong as kappa carrageenan gel. However, iota carrageenan is soluble in water with room temperature. Iotacarrageenan also has properties similar with low methoxyl pectin
contained in the green grass jelly, which both require calcium ions for the gel formation. Iota carrageenan sold in Indonesia is very rare in pure form. Of course, it will be very difficult for real
applications of this research to daily life. Calcium ion that could be added to this formulation was CaCO
3
. However, as happened with the green grass jelly with other hydrocolloid mixture, the addition of CaCO
3
into green grass jelly with carrageenan resulted in paler colors. Therefore, CaCO
3
was not added to the green grass jelly formulation. Montero and PèrezMateos 2002 pointed out that addition of calcium ions to the kappa
and iota carrageenan resulted in darker, redder, and yellower gel color. On the other hand, addition of sodium ions to the kappa and iota carrageenan resulted in lighter, greener, and bluer gel color.
Furthermore, water holding capacity of carrageenan gel increased with the addition of NaCl until the maximum concentration of 0.5 and decreased with the addition of CaCl. With the calcium ions, it
caused the helix aggregation producing weak gels and retains more water. Thus, calcium will increase syneresis of carrageenan gel.
35
E. DETERMI ATIO OF
