Compositional Analysis of Chinese Water Chestnut (Eleocharis dulcis) Cell-Wall Material from Parenchyma, Epidermis, and Subepidermal Tissues

Abstract

Chinese water chestnut (Eleocharis dulcis (Burman f.) Trin ex Henschel) is a corm consumed globally in Oriental-style cuisine. The corm consists of three main tissues, the epidermis, subepidermis, and parenchyma; the cell walls of which were analyzed for sugar, phenolic, and lignin content. Sugar content, measured by gas chromatography, was higher in the parenchyma cell walls (931 μg/mg) than in the subepidermis (775 μg/mg) or epidermis (685 μg/mg). The alkali-extractable phenolic content, measured by high-performance liquid chromatography, was greater in the epidermal (32.4 μg/mg) and subepidermal cell walls (21.7 μg/mg) than in the cell walls of the parenchyma (12.3 μg/mg). The proportion of diferulic acids was higher in the parenchyma. The Klason lignin content of epidermal and subepidermal cell walls was ~15%. Methylation analysis of Chinese water chestnut cell-wall polysaccharides identified xyloglucan as the predominant hemicellulose in the parenchyma for the first time, and also a significant pectin component, similar to other nongraminaceous monocots.

Metabolites composition and variation in processing waste of water chestnut

“…d). Ferulic acid has been reported from WC which plays very important role in cell structure and possesses many bioactivities (Ou & Kwok, ; Grassby et al ., ), but feruloylquinic acid is the first time reported from WC.…”

“…The ultraviolet (Uv) spectrum showed no characteristics absorbance than 220 nm. Database query found that the formula C 7 H 12 O 6 is probably quinic acid which usually combined with caffeic acid and formed chlorogenic acid in WC (Zhan et al ., ; Grassby et al ., ; Li et al ., ). The formula C 12 H 22 O 11 is probably sucrose.…”

“…Reports show that the special texture of WC comes from the linkage between saccharides and ferulic acid in the cell walls (Parker et al ., ; Grassby et al ., ). Because that quinic acid in WC can easily react with ferulic acid and form feruloylquinic acid, the sucrose and quinic acid conjugate in HRWC may be an intermediate product of the ferulic acid and saccharides conjugate cell walls.…”

“…Chlorogenic acid has been reported from WC (Li & Shao, ; Grassby et al ., ; Zhan et al ., ). It is a phenolic compound with many bioactivities such as anti‐inflammation, anti‐hypertension, anti‐tumour, antiviral, anti‐liver fibrosis and radical scavenging capacities etc.…”

“…Eleocharis dulcis , also known as Chinese water chestnut or water chestnut (WC) is a grass‐like sedge distributes in Asia, islands of the Pacific and Indian Oceans (Hodge, ; Grassby et al ., ). It is cultivated in many parts of Asia, and recently small‐scale cultivation has started in Australia and the USA for its edible corns which can retain a crisp texture when cooked (Parker et al ., ; Grassby et al ., ; Zhan et al ., ). The light sweet corn is also a traditional healthy food in China.…”