36 value of 141.1391 gcm
2
. Increase of carrageenan concentration will increase the rupture strength value of the gel. This pattern was also happened for the green grass jelly mixed
with several kinds of hydrocolloids, such as arabic gum Nasution 1999. Rupture strength increased by increasing arabic gum concentration and it would decrease at the concentration
more than 1.5. This is caused by the stronger bonds between the polymer formed with increasing concentrations of hydrocolloid. Glicksmann 1984 pointed out that gel rupture
strength is the value of the elasticity limit of the gel. The higher gel rupture strength values, the stronger bonds occured between the polymer that forms a gel network. Gel strength is
also affected by the type of bonding that occurs in the gel network. Based on the analysis of variety with the α = 5, rupture strength values which is not significantly different with gel
rupture strength value possessed by commercial green grass jelly are additions of carrageenan at concentrations of 2.00, 2.25, 2.50, 2.75, and 3.00.
1.2. Rupture Point
Rupture point indicates the depth of penetration at the time of gel rupture. A higher rupture point indicates that the gel is not easily broken. Commercial green grass jelly has
rupture point of 7.945 mm. Rupture point of green grass jelly without addition of carrageenan is higher than the commercial one, 13.2675 mm. Increase of carrageenan
concentration will increase the rupture point value of the gel until concentration of 2.25, then the rupture point decreased by the increase of carrageenan concentration. This
fluctuative pattern was also happened for the green grass jelly mixed with several kinds of hydrocolloids, such as xanthan gum Kurniawan 1999 and alginate Rahayu 2000. Highest
rupture point belongs to the concentration of 0.075 xanthan gum and 0.01 alginate. Higher hydrocolloids concentration, make the rupture point increased and decreased as
fluctuative as with carrageenan addition. Similar to the rupture strength, it can be assumed that every hydrocolloid has their own unique pattern of rupture point due to the increasing
of concentration. High hydrocolloid concentration will cause the bond that formed more varied and stronger. This type of bond also determines whether the formed gel is difficult to
be ruptured Rustanti 2000. Based on the analysis of variety with the α = 5, rupture point value which is not significantly different from the value of commercial green grass jelly are
with the additions of carrageenan at concentrations of 1.25, 1.50, 1.75, and 2.00 .
1.3. Rigidity
Rigidity is a quantity of load or force to do the gel deformation, prior to the breakdown or destruction of the gel. Rigidity shows the gel stiffness, where the more rigid
gel shows higher rigidity value. Commercial green grass jelly has rigidity value of 176.9837 gcm. Without addition of carrageenan, rigidity of green grass jelly is lowest, 38.1474 gcm.
Increase of carrageenan concentration will increase the rigidity value of the gel until concentration of 2.00, then the rigidity decreased for the concentration of 2.25. By
increasing carrageenan concentration, rigidity increased again, repeat the previous pattern. It was also happened for the green grass jelly mixed with several kinds of hydrocolloids, such
as xanthan gum 1999. Similar with rupture strength and rupture point, every hydrocolloid
37 has their own unique pattern of rigidity due to the increasing of concentration. Highest
rigidity value belongs to the addition of 0.075 xanthan gum. Before 0.075, gel rigidity increased by increasing of xanthan gum concentration and decreased by higher
concentration than 0.075. Rustanti 2000 pointed out that gel stiffness depends on the ability of the gel to expand and contract as the fibriller can be widened or extended without
damaging the structure of the gel. Based on the analysis of variety with the α = 5, the rigidity value which is not significantly different from the rigidity value of commercial
green grass jelly is the addition of carrageenan at concentration of 2.00. High rigidity value is also affected by the presence of sodium ions. The monovalent ions are bound to the
helix of carrageenan and neutralising partially the sulphite bonds, by this way the double helix are grouping increasing the rigidity of the gel Montero and PèrezMateos 2002.
2. Color
