19
2.2. Level of Acidity pH AOAC 2000
Measurement of pH was conducted on the acidity of green grass jelly’s syneresis water. Before used, the pH meter was calibrated with buffer solution of pH
4.00 and pH 7.00. Furthermore, because the green grass jelly is semi solid product, it is necessary to prepare the sample before pH measurements performed. Green grass jelly
homogenized by shredding into small parts, then chopped or crushed until smooth. Then, 20 ml of syneresis water was placed in a glass beaker, its pH value then
measured.
2.3. Gel Syneresis AOAC 1995
Gel syneresis observed according to AOAC 1995 method by storing gel at refrigerator temperature 10°C for 24 hours, 48 hours, and 72 hours. Each gel was put
into the cup to hold the water released from the gel during storage. Gel syneresis was calculated by measuring the weight loss during storage and compared with the initial
weight of the gel. Gel Syneresis =
AB A
×100 Where:
A = initial weight of the gel before storing gram B = weight of the gel after storing gram
3. DETERMI ATIO OF HYDROCOLLOID TYPE A D CaCO
3
CO CE TRATIO
This stage used various hydrocolloids, such as 2 alginate, 2 LMP, 2 mixture of alginate and LMP 1:1, and 2 mixture of kappa and iota carrageenan 1:1, combined with
green grass jelly extract 6.67. In determination of CaCO
3
concentration, the concentrations used were 0 and 1. Moreover, there was only one NaHCO
3
concentration added, the chosen concentration from the previous stage. This treated green grass jelly would be steamed
at 100°C for 5 minutes. Determination of hydrocolloid type and CaCO
3
concentration with steaming treatment would be observed based on the subjective color and gelling capability.
The flow diagram of this stage is shown in Figure 12.
20 Green grass leaves Premna oblongifolia Merr.
and water 1:15 Crushed
Filtered using filter cloth Green grass extract
Formed in gelling container Gelling for ± 5 hours at room temperature
Green grass jelly Steamed 100
o
C, 5 minutes Observation of color and gelling capability
Figure 12. Procedure of hydrocolloid type and CaCO
3
concentration determination
4. DETERMI ATIO OF
SELECTED HYDROCOLLOID
CO CE TRATIO WITH STEAMI G
This stage used the selected hydrocolloid, mixture of kappa and iota carrageenan 1:1. The concentrations used were determined by variance of 0.25 from 1.25 to 3.00.
This treated green grass jelly would be steamed at 100°C for 5 minutes. Determination of selected hydrocolloid concentration with steaming treatment would be observed based on the
parameters of color with Chromameter CR 200, gel texture with Stevens LFRA Texture Analyzer, syneresis rate, and pH changes. Parameters of texture observed were rupture
strength gcm
2
, rupture point cm, and rigidity gcm. From these results, three best formulas would be selected. The flow diagram of this stage is shown in Figure 13.
0 and 1 CaCO
3
NaHCO
3
2 Hydrocolloid
21 Green grass leaves Premna oblongifolia Merr.
and water 1:15 Crushed
Filtered using filter cloth Green grass extract
Formed in gelling container Gelling for ± 5 hours at room temperature
Green grass jelly Steamed 100
o
C, 5 minutes Observation of color, texture, syneresis rate, and pH changes
Figure 13. Procedure of selected hydrocolloid concentration determination
4.1. Gel Texture
Gel texture was measured by using Stevens LFRA Texture Analyzer. Measurement conditions were used according to the research that has been conducted
by Camus 2000. The distance between the probes and the gel of 55 mm, probe speed of 2 mmsec, chart paper speed of 30 cmmin, the probe diameter of 0.5 inches,
sensitivity of 100 mV, and strain of 50. The general curve obtained from the Stevens LFRA Texture Analyzer can be seen in Figure 14.
Figure 14. The general curve obtained from the Stevens LFRA Texture Analyzer
NaHCO
3
1.25 3.00 Selected
Hydrocolloid
Rupture Penetration cm R
u p
tu re
W ei
g h
t g
22 Parameters observed in this measurement were gel rupture strength, rupture point, and
rigidity. Calculation for rupture strength, rupture point, and rigidity was done by using the formulas from Angalet 1986 and Fry and Hudson 1983 as follow:
Rupture strength g cm
2
=
Load of rupture Surface area of probe base
=
AB 1.27 cm
2
Rupture Point = Rupture penetration = AC
Rigidity g cm =
Load of rupture Rupture penetration
×
probe speed paper speed
=
AB AC
5. SE SORY EVALUATIO
This stage was a continuation of the previous stage, where three green grass jelly formula that showed the best value on the parameters of color, texture, syneresis, and pH
changes would be selected as the one chosen formula by consumers’ organoleptic acceptance. Type of test used was hedonic rating test Meilgaard et al. 1999. In hedonic rating test,
panelists asked to reveal personal perceptions about preferences of like or dislike the green grass jelly products. Three chosen formula and one formula without the addition of
hydrocolloid as control would be judged based on color, aroma, texture, flavor, and overall parameters. Panelists needed at least 70 untrained panelists. The scale used is the category
scale with seven values.
6. FU CTIO AL PROPERTIES A ALYSIS
Kategori