The amount of expressible water(EW) for the samples was measured by Avanti J-E centrifuge(Beckman Coulter Inc. Fullerton. CA. USA). Samples(3 0.2 g) of gels were weighed and placed between two layers of filter paper(No. 1029- 11 cm. Hangzhou Xinhua. Filter Paper Co. Ltd. Hangzhou. Zhejiang. China). Samples were then placed at the bottom of 50 ml centrifuge tubes and centrifuged at 1000 g for 15 min. After centrifugation. gels were weighed again. The expressible water is calculated as: Ew(W- W)/W x 100. where w is the initial weight of gel and is the final weight of gel(Mao& Wu. 2007). Eight replicates of measurements were taken