CHARACTERIZATION OF CELL-WALL POLYSACCHARIDES OF JICAMA (PACHYRRHIZUS-EROSUS) AND CHINESE WATER CHESTNUT (ELEOCHARIS-DULICIS)

Alcohol insoluble solids (AIS) from jicama and Chinese water chestnut were isolated and analyzed to elucidate the similarity in texture between these two crispy vegetables. Pectins were the largest AIS component of both vegetables, comprising approximately 50% of AIS. Further analysis showed a similar composition of water soluble, chelator soluble, and alkaline soluble pectins in both jicama and water chestnut. Water chestnut contained a much larger hemicellulose component and a correspondingly smaller cellulose and lignin component than jicama. Fractionation of the hemicellulose and examination of molecular weight distribution and neutral sugar composition of various fractions revealed major differences between the two vegetables. These differences in structure and composition of hemicellulose may explain the observed differences in textural properties of these two crispy vegetables.