Syneresis Rate DETERMI ATIO OF aHCO

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

Observation of syneresis was performed during 0 hour, 24 hours, 48 hours, and 72 hours after steaming. It was later processed in the form of graphs and linear regression equation. The whole results of syneresis are presented in Appendix 7. Graphs of syneresis can be seen in Figure 17. This graph shows that the addition of 0.125 NaHCO 3 is able to reduce the rate of green grass jelly syneresis compared with treatment without the addition of NaHCO 3 . The addition of 0.125 NaHCO 3 also has lower rate of syneresis compared with the addition of 0.583 NaHCO 3 . In terms of the syneresis rate, the chosen treatment was 0.125 of NaHCO 3 concentration. There is an assumption that syneresis rate of hydrocolloid compound depends on the pH of the product. pH about 7 is a good condition that can inhibit the syneresis rate of low methoxyl 31 pectin occured. Furthermore, chain aggregation of end linear fibriller to another end linear fibriller was promoted. An increase in the salt concentration from 0.05 to 0.2 M enhanced low methoxyl pectin aggregation so that the fibriller bound become so close Yoo et al. 2003. Montero and PèrezMateos 2002 stated that the effect of cations depend on concentration. At low concentration, they appear to have stabilising effect, whereas at very high concentration, they appear to have opposite effect. This may mean the saturation of anionic groups occurs at certain. Figure 17. Syneresis graphs of NaHCO 3 addition treatments Marudova and Jilov 2002 pointed out that pectin gel strength and viscoelasticity decreased in the presence of high concentration ions. It may be happened due to the decrease in crosslinking junctions between the pectin chains. The decrease is most considerable with increasing salt concentration that is with increasing ionic strength in the solution. By the decrease in crosslinking junctions, the water will be released from the gel. Sodium ion itself has salting out effects. The presence of the ion inside gel structure can not be dispersed uniformly. Gel parts with high concentration of sodium ion will draw the water from another gel parts to balance the ionic concentration. It will lead to the competition between hydrocolloid components and salt to get the water.

4. pH Changes