Water chestnuts

Description

• Water chestnuts (Eleocharis dulcis) are aquatic corms commonly used in Asian cuisine.

• They remain crisp even after cooking, giving them a unique technological advantage in food applications.

• Flavor is mildly sweet, fresh, and neutral, making them versatile in both savory and sweet dishes.

• Available fresh, peeled, canned, dried, or as flour/starch.

Indicative nutritional values per 100 g

(Approximate values for raw, peeled water chestnuts.)

• Energy: 90–100 kcal

• Carbohydrates: 22–24 g

  • Sugars: ~4–5 g

  • Dietary fiber: 3–4 g

• Proteins: 1–2 g

• Lipids: <0.5 g

  • SFA (first occurrence): extremely low

  • MUFA: negligible

  • PUFA: negligible

  • TFA: absent

• Minerals: potassium, manganese, copper, magnesium

• Vitamins: B6, riboflavin, vitamin C (reduced after cooking or canning)

Key constituents

• Carbohydrates: mainly starches (amylose/amylopectin) and soluble sugars.

• Phenolic antioxidants: ferulic acid and catechin derivatives.

• Minerals: potassium (notably high), manganese, copper.

• Bioactive compounds: flavonoids, saponins (trace), and water-soluble antioxidants contributing to functional properties.

Production process

• Harvesting: aquatic corms collected from freshwater fields after full maturity.

• Cleaning and peeling: mechanical removal of outer skin; manual trimming for premium grades.

• Thermal treatment: blanching or light boiling to stabilize enzymes.

• Processing options:

  • Fresh-packed in modified atmosphere.

  • Canned in brine (most common).

  • Dehydrated/dried slices.

  • Milled into water chestnut flour/starch.

• Quality control: microbiological, physical, and sensory analysis under GMP/HACCP programs.

Physical properties

• Appearance: round, white, crunchy, with smooth surface when peeled.

• Texture: exceptionally crisp even after heating due to cell-wall integrity and heat-stable phenolic cross-linking.

• Moisture content: 70–80% (fresh); <10% (dried).

• pH: slightly acidic (5.8–6.5).

• Density: varies with processing; canned forms are denser due to brine absorption.

Sensory and technological properties

• Taste: mild, slightly sweet, neutral.

• Aroma: faint, fresh, earthy.

• Color: white to off-white.

• Technological roles:

  • Maintains crunchiness after cooking (unique among vegetables).

  • Adds texture contrast in stir-fries and fillings.

  • Flour form provides thickening, binding, and gluten-free functionality.

  • Stable during pasteurization, sterilization, and high-heat culinary methods.

Food applications

• Stir-fries, Asian-style dishes, curries, and soups.

• Dumpling fillings, spring rolls, wontons.

• Salads and cold dishes for texture enhancement.

• Canned products for ready meals.

• Crisps or chips when sliced and fried.

• Water chestnut flour:

  • Gluten-free bakery items

  • Thickening in sauces and soups

  • Traditional Asian sweets

Nutrition & health

• Low-fat, low-calorie ingredient suitable for balanced diets.

• Rich in potassium, contributing to normal blood pressure regulation.

• Provides dietary fiber that supports digestion.

• Contains antioxidants with mild anti-inflammatory potential.

• Naturally gluten-free, suitable for gluten-restricted diets.

• High water content contributes to hydration and low energy density.

Portion note

• Typical culinary portion: 50–80 g fresh or canned water chestnuts in a meal.

• For flour: 10–30 g depending on thickening or baking purpose.

Allergens & intolerances

• Naturally free from major allergens (gluten, dairy, nuts, soy, seafood).

• Rare individual sensitivities to aquatic plants may occur.

• In canned products, verify absence of preservatives for sensitive consumers.

Storage & shelf-life

• Fresh (unpeeled): 1–2 weeks refrigerated.

• Fresh peeled: 3–5 days under refrigeration in water (changed daily).

• Canned: 1–3 years unopened; 2–3 days after opening if refrigerated in clean water.

• Dried/flour: 12–24 months in sealed, cool, dry storage.

Safety & regulatory

• Classified as a vegetable ingredient; no specific ADI defined.

• Must comply with hygiene and contaminant limits according to regional regulations.

• Typical checks include microbial load, pesticide residues, and heavy metals depending on growing region.

• Production must follow GMP/HACCP frameworks.

Labeling

• Ingredient declaration: “Water chestnuts” or “Water chestnut (Eleocharis dulcis)”.

• Canned versions must list brine or water and any additives (e.g., citric acid).

• Gluten-free claim allowed if cross-contamination is controlled.

Troubleshooting

• Loss of crunchiness:

  • Caused by prolonged cooking or poor raw-material quality; use fresh, high-grade corms.

• Discoloration:

  • Enzymatic browning; prevent with acidification (e.g., lemon/citric acid) or proper blanching.

• Off-flavors in canned product:

  • Related to brine oxidation; improve packaging or reduce storage time.

• Hard center in dried products:

  • Rehydrate longer or slice thinner before drying.

Sustainability & supply chain

• Often cultivated in rotational wetland systems that support biodiversity.

• Low environmental impact compared to conventional agriculture due to aquatic growth requirements.

• Responsible water management needed to avoid runoff contamination.

• Processing waste (peels, trimmings) can be used as animal feed or compost.

Main INCI functions (cosmetics)

(When used as “Water Chestnut Extract” or derivatives)

• Skin conditioning

• Soothing and hydrating agent

• Antioxidant botanical component

• Astringent/toning functionality

Conclusion

Water chestnuts are a versatile, nutritious, and texturally unique food ingredient widely used in both traditional and modern recipes. Their ability to retain crunchiness during cooking makes them valuable in processed foods and ready meals. With a clean nutritional profile, neutral flavor, and wide applicability—including gluten-free and plant-based products—water chestnuts can enhance sensory quality while supporting healthier formulations. Sustainable cultivation and minimal allergenic potential further reinforce their value in the global food industry.

Mini-glossary

• SFA – Saturated fatty acids. Excess intake may increase LDL cholesterol; water chestnuts contain extremely low amounts.

• MUFA – Monounsaturated fatty acids. Generally beneficial for heart health.

• PUFA – Polyunsaturated fatty acids. Important for metabolic and cardiovascular functions.

• TFA – Trans fatty acids. Industrial TFAs are harmful; water chestnuts contain none.

• GMP/HACCP – Good Manufacturing Practices / Hazard Analysis and Critical Control Points. Systems ensuring hygiene, safety, and traceability in food production.

• BOD/COD – Biological oxygen demand / chemical oxygen demand. Indicators used to measure the environmental impact of wastewater in food-processing operations.

References__________________________________________________________________________

Wei RR, Ma QG, Sang ZP, Dong JH. Studies on phenylpropanoids from Eleocharis dulcis and their hepatoprotective activities. Zhongguo Zhong Yao Za Zhi. 2021 Mar;46(6):1430-1437. doi: 10.19540/j.cnki.cjcmm.20200821.201. 

Abstract. To study phenylpropanoids from Eleocharis dulcis and their hepatoprotective activities. The compounds were separated and purified from ethyl acetate part by conventional column chromatography and preparative liquid chromatography, and their structures were identified by various spectral techniques. The HL-7702 cells damage model of hepatocytes induced by APAP was used to screen and evaluate the hepatoprotective activities of these compounds. Sixteen compounds were isolated from ethyl acetate part of E. dulcis, and their structures were identified as 6'-(4″-hydroxy-3″-methoxy-phenylpropenyl)-1-(10-methoxy-phenylacetone)-1'-O-β-D-glucopy-ranoside(1), susaroyside A(2), clausenaglycoside B(3), clausenaglycoside C(4), clausenaglycoside D(5), emarginone A(6), emarginone B(7), thoreliin B(8), 4-O-(1',3'-dihydroxypropan-2'-yl)-dihydroconiferyl alcohol 9-O-β-D-glucopyranoside(9), 2-[4-(3-methoxy-1-propenyl)-2-methoxy-phenoxy]-propane-1,3-diol(10), 6'-O-(E-cinnamoyl)-coniferin(11), methyl 3-(2-O-β-D-glucopyranosyl-3,4,5,6-tetramethoxyphenyl) propanoate(12), clausenaglycoside A(13), 9-O-(E-cinnamoyl)-coniferin(14), 6'-O-(E-cinnamoyl)-syringin(15), 2'-O-(E-cinnamoyl)-syringin(16). Among them, compound 1 was a new compound. Compounds 2-16 were isolated from this plant for the first time. Among them, compounds 2 and 8 showed certain hepatoprotective activities.

Li G, Nie H, Huang S, Li X, Wu S, Tang X, Song M, Luo Y. Taste Compound Generation and Variation in Chinese Water Chestnut (Eleocharis dulcis (Burm.f.) Trin. ex Hensch.) Processed with Different Methods by UPLC-MS/MS and Electronic Tongue System. Foods. 2022 Nov 30;11(23):3869. doi: 10.3390/foods11233869. 

Abstract. Chinese water chestnut (CWC) is popular among consumers due to its unique flavor and crisp and sweet taste. Thus far, the key substances affecting the taste compound of CWC are still unclear. In this study, we used UPLC-MS/MS and an electronic tongue system to study the effects of four typical steaming and cooking methods, cooking without peel for 10 min (PC), steaming without peel for 15 min (PS), cooking with peel for 30 min (WPC), steaming with peel for 30 min (WPS), on the taste compound generation and variation of CWC, and revealed the secret of its crisp and sweet taste. The results show that the electronic tongue can effectively identify the taste profile of CWC, and the effective tastes of CWC were umami, bitterness, saltiness, and sweetness. We screened 371 differential compounds from 640 metabolic species. Among them, nucleotides and their derivatives, carbohydrates, organic acids and their derivatives, and amino acids and their derivatives are closely related to the key taste of CWC, and these compounds affected the taste of CWC through six related metabolic pathways: oxidative phosphorylation and purine metabolism; alanine, aspartate, and glutamate; bile secretion; amino sugar and nucleotide sugar metabolism; the phenylpropane pathway; and toluene degradation. This study reveals the potential metabolic causes of taste compound generation and variation in the taste of CWC.

Gu Y, Yang X, Shang C, Thao TTP, Koyama T. Inhibition and interactions of alpha-amylase by daucosterol from the peel of Chinese water chestnut (Eleocharis dulcis). Food Funct. 2021 Sep 20;12(18):8411-8424. doi: 10.1039/d1fo00887k.

Abstract. The alpha-amylase inhibitory effect of daucosterol purified from the peel of Chinese water chestnut (CWC), a common Chinese vegetable, was assessed. The alpha-amylase inhibitory properties were elucidated by enzyme inhibition, fluorescence quenching and molecular docking experiments. It was found that three saponins from CWC peel exhibited potent inhibitory activity on alpha-amylase and daucosterol was found to be the main inhibitory factor against alpha-amylase with a mixed-type mode. Strong fluorescence quenching of alpha-amylase was observed under static fluorescence quenching with hydrophobic interactions with daucosterol. Molecular docking revealed that the conformation of daucosterol in the high-affinity sites I and II of alpha-amylase was optimum, and hydrophobic interactions were produced by daucosterol aglycone, and hydrogen bonding by the β-D-glucopyranosyl residue. Ingested daucosterol suppressed the elevation of blood glucose levels through inhibition of alpha-amylase in the small intestine in starch-loaded mice. This study provides data supporting the potential benefit of daucosterol from CWC peel in the treatment of diabetes.

Grassby T, Jay AJ, Merali Z, Parker ML, Parr AJ, Faulds CB, Waldron KW. Compositional analysis of Chinese water chestnut (Eleocharis dulcis) cell-wall material from parenchyma, epidermis, and subepidermal tissues. J Agric Food Chem. 2013 Oct 9;61(40):9680-8. doi: 10.1021/jf401863n. 

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.