2.4. Syneresis measurement
Syneresis measurement was executed by the method of Charoenrein, Tatirat, and Muadklay (2008) with modification. The top of syringe was cut off to put into a 50 mL centrifuge tube and about 15 holes were drilled at the bottom. Then, a part of needle was cut down for fitting in the centrifuge tube. The equipment as illustrated in Fig. 1, was used to measure syneresis. Afterwards, the thawed gel samples were removed from syringes to those drilled syringes with filter paper at the bottom. Next, the drilled syringes were placed in centrifuge tubes. The tubes were then centrifuged at 4000 g for 15 min. The percentage of syneresis was then calculated as the ratio of the amount of liquid separated (g) to the total weight(g) of the gel before centrifugation.