Palauan has the habit of Alocasia macrorrhiza, a large plant with a very stout trunk, growing in dense clumps, . Leaves are very big, hastate, up to 1.5 meters in length. Petioles are large and stout, up to 2.5 meters long and 10 centimeters in diameter. Spathe is 30 to 60 centimeters long and oblong. Spadix is cylindric, about 15 centimeters long, 2 to 3 centimeters wide. Seeds are globose and about 5 millimeters wide.
- In ravines along streams in Luzon (Sorsogon), Mindoro, Samar, Leyte, Palawan and Mindanao.
- In some regions planted for its edible corms or as an ornamental.
- Occurs in Java and Borneo to New Guinea.
- Contains 62.61% moisture, 1.05% ash, 0.81% protein, 0.09% fat (ether extract), 33.87% carbohydrate, and 1.57% crude fiber providing 1,430 calories per kilo.
- Study reports the rootstock to contain 0.5% starch.
- Yellow-fleshed cultivars yielded
high carotenoid concentrations, substantial amounts of zinc, iron and calcium.
- In a study of 34 cultivars, ß-carotene varied from 50 to 4486 µg/100g; yellow-fleshed cultivars yielded higher carotenoid concentrations. Mineral content of ten cultivars yielded (wet weight basis) substantial concentrations of zinc (5.4-46.1 mg/100g), iron (0.3-0.8 mg/100g) and calcium (121-305 mg/100g).
(see study below) (6)
- Nutrient analysis per 100 grams of edible portion of corms
of Cyrtosperma chamissonis yielded 131 calories, 0.9 g protein, 31 g carbohydrate, 334 mg calcium, 56 mg phosphorus, 1.2 mg iron, 0.045 mg thiamin, 0.074 mg riboflavin, and 0.88 mg niacin. (7)
- Yellow (YP) and white (WP) sections of giant swamp taro (GST) yielded 40.0 g/kg and 51.5 g/kg (dry weight), respectively of pure mucilage made up of D-glucose (44.95-78.85%), D-galactose (8.70-25.35%), D-mannose (3.20-10.45%), D-arabinose (2.45-5.20%) and small amounts of glucoronic acid and rhamnose. (see study below) (10)
- Emmenagogue, ecbolic.
- Studies have shown antioxidant property.
- Plant contains calcium oxalate crystals which cause very unpleasant sensations of needles stuck in the mouth and tongue. They are easily neutralized by drying or cooking or by steeping in water. (8) (9)
Edibility / Nutrition
- Large rootstocks are eaten when food is scarce.
- Corms are edible: roasted, steamed or boiled.
- In the Pacific atoll islands, it is the most important staple food.
- Peeled and chopped stalks used in soups.
- Toxicity caution: Roots require hours of cooking to reduce toxicity in the corms.
- As a
staple food it is an important source of carbohydrates. Although rich in carbohydrates, it is poor in other constituents.
- Of limited medicinal use in the Philippines.
- Decoction of spadix used as emmenagogue and ecbolic.
- In Kirbati, Catala, yellow mold from sliced and sundried corms used to treat skin infections.
• Comparative Study of Alcohol Yield of Acid Hydrolyzates: Study evaluated the potential alcohol yields from the acid hydrolysis of corms of three araceae plants: gabi (colocasia esculenta) 35.90%, palauan (Cystrosperma merkusii) 21.93%, and San Fernando (Xanthoma sagittifolium) 26.73%. There were no significant differences in the theoretical alcohol yield. Results suggest a potential of utilizing the three plant types for alcohol production. (2)
• Carotenoid and Mineral Content of Cultivars: Giant swamp taro (Cyrtosperma merkusii) is an important food in the mountain islands of Micronesia. Study showed the cultivars to be rich in carotenoid concentration with substantial amounts of zinc, calcium, and iron. Cultivars were acceptable in taste and production factors. Study suggests promotion for its potential health benefits. (see constituents above) (6)
• Mucilage / Antioxidant Activity: Study investigated the mucilage profile and antioxidant properties of giant swamp taro tubers. Antioxidant activity of YP was higher than those of WP; chelating ability and reducing power increased with mucilage content. Effective concentration (EC50) of mucilages (WP 1.28 ± 0.05 mg/mL; YP 1.42 ± 0.04 mg/mL) were lower than that of citric acid. YP and WP mucilages are usually excellent sources of chelating agents. (see constituents above) (10)