Chinese waterchestnut

Chinese waterchestnut (Eleocharis dulcis (Burm. f.) Trin. ex Henschel) is a tropical member of the sedge family and as its name implies it is an aquatic species. Plants consist of four to six upright tubular stems approximately 1.5 m tall. Vegetatively propagated, the corms (or tubers), the edible portion, are produced at the end of underground stems (or rhizomes). A botanical novelty ten years ago, although in its wild form it was reputedly harvested by Aboriginals, it is now produced and marketed commercially in Australia, substituting for the importation of canned produce. For Australia, the Australian produce has the advantage of being marketed fresh (the tinned product lacks quality and consumer appeal) but it is only available over the period June to November, thereby limiting the effectiveness of import substitution. Premium Australian waterchestnuts are > 4.0 cm in diameter (Photo 1), and better than those from traditional production zones in Thailand (Suphanburi), China (Guai Lin) and Taiwan (Tainan County); but according to connoisseurs, Australian produce at times lacks sweetness and tastes starchy. The crispy texture, which is retained after processing or cooking, is due to the presence of the ferulic acid-containing hemicelluloses in cell walls of the chestnuts. The product is favoured for `fresh' stir-fry mixes, and currently the tinned form is used to supply this product line in supermarkets. It also forms the basis for heavily sweetened drinks in Asia, and is sold in syrup for use as a desert. A tradition of production in Taiwan and China and the recent introduction of a canning industry in Thailand underpin the world trade in waterchestnut, and the US is the major importer of the canned form. To assist new and prospective growers, an Australian Aquatic Vegetables Development Committee (Midmore, 1997) has been established to provide information on cooperative establishment of quality assurance, grading, marketing opportunities and coordination of planting and production goals.