Determination of Antinutritional Changes in Elephant Foot Yam (Amorphophallus Paeoniifolius Dennst- Nicolson) Cultivars during Storage

Amorphophallus paeoniifolius DennstNicolson belongs to Araceae family and its common names are Elephant yam, Elephant bread, Elephant foot yam, Suran, Sweet yam, Jimikand. Other common names are Karak-kavanai (Tamil); Konjac, Konniaku, Konnyaku (Japan); Mo-yu (China); Ol (Assam) etc., which varies from region to region. In India, it is commonly known as "Suran" or "Elephant foot yam” and largely cultivated throughout the plains for using its corm (bulb) as food. It is a very popular vegetable due to its high productivity, nonirritant taste, and maximum monetary return within a short period of time [1]. They have played major role in the history of human diet, since they could be collected from the wild and consumed by many of the worlds poorest and most foods insecure households [2]. It contains moisture 74.8%; ash 0.73 %; fat 0.38%; protein 5.1%; carbohydrates 18.4%; crude fibre 0.6% and alkaloid [3, 4]. It is rich in nutrients like minerals (Ca, K, P, Zn), vitamins (A, B1, B2) and contains starch and carbohydrates as a major energy source. Potassium is the most abundant (327.83 mg/100g) macro mineral followed by phosphorus (166.91 mg/100g), calcium (161.08 mg/100 g) and iron (3.43 mg/100 g) [5]. The mean soluble oxalate content (13.53 mg/100 g) of yam is safe from the viewpoint of accumulation of urinary oxalate leading to kidney stones. This tuber is consumed by many people as a food and widely used in many Ayurvedic preparations [6]. The tubers of elephant foot yam are anodyne, anti-inflammatory, anti-haemorrhoidal, haemostatic, expectorant, carminative, digestive, appetizer, stomachic, anthelmintic, liver tonic, aphrodisiac, emmenagogue, rejuvenating and tonic [7]. They are traditionally used in arthralgia, elephantiasis, tumors, inflammations, haemorrhoids, haemorrhages, vomiting, cough, bronchitis, asthma, anorexia, dyspepsia, flatulence, colic, constipation, helminthiasis, hepatopathy, splenopathy, amenorrhea, dysmenorrhoea, seminal weakness, fatigue, anaemia and general debility [8]. The tuber is reported to have antiprotease activity, central nervous system depressant activity, analgesic activity cytotoxic activity [9-12]. It is difficult to ascertain whether the tubers can be relied upon as good sources of minerals because of the presence of anti-nutrition substances (oxalate), which render the minerals, in them unavailable to the consumers [13]. These corms are consumed by many people as a food and widely used in many ayurvedic preparations [12] because it contains different bioactive components like alkaloids, flavonoids, phenols, vitamins, minerals etc. [14-18]. Oxalate is Abstract Elephant foot yam plays a key role in household food security in South East Asian food system, but its benefits have been negated due to presence of antinutritional compounds. The eleven cultivars viz., BCA-1, BCA-2, BCA-4, BCA-5, BCA-6, NDA-4, NDA-5, NDA-9, IGAM-1, AC-28 and Gajendra were grown and after harvesting stored at ambient temperature upto three months to analyze the antinutritional changes at monthly intervals. The purpose of this study was to determine the oxalate content in elephant foot yam cultivars during storage condition. While, it was noticed a significantly decrease in all cultivars during storage. The ranges of antinutrient contents were found to be: water soluble oxalate (WSO) 25.61-11.83 mg/100g, total soluble oxalate (TSO) 33.83-18.26 mg/100g, calcium oxalate 15.28-5.97 mg/100g and total oxalate (TO) 37.57-20.70 mg/100g at different stages during storage. The entire investigated samples were found to be low oxalate content in all cultivars, which was safer from the viewpoint of accumulation of urinary oxalate leading to kidney stone. This information will provide researchers with the ability to develop desirable cultivars having high yield and better antinutritional profile.