Dioscorea Spp.) Tropical and Subtropical Agroecosystems, Vol
Total Page:16
File Type:pdf, Size:1020Kb
Tropical and Subtropical Agroecosystems E-ISSN: 1870-0462 [email protected] Universidad Autónoma de Yucatán México Shajeela, P.S.; Mohan, V. R.; Jesudas, L. Louis; Tresina Soris, P. NUTRITIONAL AND ANTINUTRITIONAL EVALUATION OF WILD YAM (Dioscorea spp.) Tropical and Subtropical Agroecosystems, vol. 14, núm. 2, mayo-agosto, 2011, pp. 723-730 Universidad Autónoma de Yucatán Mérida, Yucatán, México Available in: http://www.redalyc.org/articulo.oa?id=93918231037 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Tropical and Subtropical Agroecosystems, 14 (2011): 723-730 NUTRITIONAL AND ANTINUTRITIONAL EVALUATION OF WILD YAM (Dioscorea spp.) [EVALUACIÓN DEL VALOR NUTRICIONAL Y FACTORES ANTINUTRICIONALES DE Dioscorea spp. SILVESTRE] P.S. Shajeela1, V. R. Mohan2*, L. Louis Jesudas3 and P. Tresina Soris2 1PG & Research Department of Botany, St. John’s College, Palayamkottai, Tamil Nadu, India. 2Ethnopharmacology Unit, Research Department of Botany, V.O.Chidambaram College, Tuticorin, Tamil Nadu, India. 3PG & Research Department of Botany, St. Xavier’s College, Palayamkottai, Tamil Nadu, India. *Corresponding Author SUMMARY RESUMEN The wild yam tubers consumed by the tribes Los tubérculos de variedades silvestres de Dioscorea Kanikkars / Palliyars of South- Eastern slopes of spp. Son consumidos por las tribus Kanikkars / Western Ghats, Tamil Nadu (Dioscorea alata, D. Palliyars de la región sur y oriental de los Ghats bulbifera var vera, D. esculenta, D. oppositifolia var Occidentales de Tamil Nadu. Dioscorea alata, D. dukhumensis, D.oppositifolia var. oppositifolia, D. bulbifera var vera, D. esculenta, D. oppositifolia var pentaphylla var. pentaphylla, D. spicata, D. tomentosa dukhumensis, D.oppositifolia var. oppositifolia, D. and D. wallichi) were evaluated for its nutritional pentaphylla var. pentaphylla, D. spicata, D. tomentosa quality. From the present investigation, it is observed y D. wallichi fueron evaluados en cuanto a su calidad that most of the wild edible yams were found to be a nutricional. Se encontró que fueron una buena fuente good source of protein, lipid, crude fibre, starch, de protein, lípidos, fibra cruda, almidón, vitaminas y vitamins and minerals. Antinutritional substances like minerales. Adicionalmente se cuantificó el contenido total free phenolics, tannins, hydrogen cyanide, total de fenoles totales libres, taninos, cianuro de hidrógeno oxalate, amylase and trypsin inhibitor activities were y oxalatos totales. Se cuantificó también la actividad quantified. de los inhibidores de amilasa y tripsina. Key words: Proximate and mineral composition; Palabras claves: composición próximal; contenido de vitamins; in vitro digestibility; antinutrients. minerales; vitaminas; digestibilidad in vitro. INTRODUCTION of dietary energy in the form of carbohydrates in developing countries (Ugwu, 2009). With ever-increasing population pressure and fast depletion of natural resources, it has become Yams (Dioscorea) belong to Dioscoreaceae family. extremely important to diversify the present-day They are herbaceous plants with twine. Approximately agricultural in order to meet various human needs 600 Dioscorea species are eaten in various parts of the (Janardhanan et al., 2003). The world food crisis has world. (Agbor-Egbe and Treche, 1995). Yams, the been and will continue to be a major obstacle to edible starchy tubers, are of cultural economic and humanity. The observed interest in search for nutritional importance in the tropical and subtropical alternative / additional food and feed ingredients is of regions of the world (Coursey, 1967). Yam has been paramount importance mainly for two reasons, one is suggested to have nutritional superiority when the low production of oil seeds and grains and another compared with other tropical root crops. They are is the stiff competition between man and the livestock reported as good sources of essential dietary nutrients industry for existing food and feed materials (Baquar and Oke, 1976; Bhandari et al., 2003; (Siddhuraju et al., 2000). Root and tubers are the most Shanthakumari et al., 2008; Maneenoon et al., 2008; important food crops since time immemorial in the Arinathan et al., 2009). Earlier reports have also tropics and subtropics (Behera et al., 2009). Roots and pointed out that a few yam species contain some toxic tubers refers to any growing plant that stores edible compounds and can impact serious health material in subterranean root, corm and tuber. The complications (Anthony, 2004). Some species of wild nutritional value of roots and tubers lies in their yams, particularly wild forms, are toxic and / or potential ability to provide one of the cheapest sources unpalatable, taste bitter and cause vomiting and 723 Shajeela et al., 2011 diarrhoea when large amount are ingested without lipid and NFE by the factors 16.7, 37.7 and 16.7 proper processing or if eaten raw (Webster et al., respectively (Siddhuraju et al., 1996). From the triple 1984). acid digested sample, sodium, potassium, calcium, magnesium, iron, copper, zinc and manganese were These wild yams make a significant contribution in the analyzed using an atomic absorption diets of the tribal people of India. The tubers were spectrophotometer (Perkin Elmer Model 5000) (Issac found with a high amount protein, a good proportion and Johnson, 1975). Phosphorus was estimated of essential amino acids and appeared as a fairly good colorimetrically (Dickman and Bray, 1940). The total source of many dietary minerals. However, their wider starch was determined by the titrimetric method of utilization is limited due to the presence of some toxic Moorthy and Padmaja (2002). The antinutritional and antinutritional factors. In India the cooked wild factors, total free phenolics (Sadasivam and tubers are known to be consumed by the Palliyar and Manickam, 1996), tannins (Burns, 1971), hydrogen Kanikkar tribes (Arinathan et al., 2007; cyanide (Jackson, 1967), total oxalate (AOAC, 1984), Shanthakumari et al., 2008) living in South-Eastern trypsin inhibitor activity (Sasikaran and Padmaja, slopes of Western Ghats, Tamil Nadu. Information 2003) and amylase inhibitor activity (Rekha and regarding the chemical and nutritional content of wild Padmaja, 2002). In vitro protein digestibility was edible tuber is meager (Babu et al., 1990; Nair and determined using the multi-enzyme technique (Hsu et Nair, 1992; Rajyalakshmi and Geervani, 1994; al., 1977) and in vitro starch digestibility was assayed Shanthakumari et al., 2008; Alozie et al., 2009; by Padmaja et al. (2001). Arinathan et al., 2009). Studies of nutritional value of wild plant food are of considerable significance since RESULTS AND DISCUSSION it may help to identify long forgotten food resources. In this context, an attempt was made to understand the The crude protein (Table 1) content of the various chemical composition and antinutritional factors of the species of Dioscorea tubers investigated in the present under utilized tubers of nine species of Dioscorea to study was found to be in agreement with the earlier suggest ways and means to remove the antinutritional / investigation in the species of Dioscorea tubers toxins and make the edible tubers as the safe food (Onyilagha and Lowe, 1985; Rajyalakshmi and sources for mass consumption. Geervani, 1994; Akissoe et al., 2001; Shanthakumari et al., 2008; Alozie et al., 2009; Arinathan et al., MATERIALS AND METHODS 2009). Among the two varieties of D. oppositifolia tubers, the variety dukhumensis contained more crude Nine samples of wild yam tubers (Dioscorea alata, D. protein than the variety oppositifolia. This value is bulbifera var vera, D. esculenta, D. oppositifolia var found to be consonance with earlier reports (Arinathan dukhumensis, D.oppositifolia var. oppositifolia, D. et al., 2009). The crude lipid content of D. pentaphylla var. pentaphylla, D. spicata, D. tomentosa oppositifolia var dukhumensis was found to be higher and D. wallichi) grown in sandy loam soil consumed when compared to the presently investigated other by the tribal Kanikkars / Palliyars were collected using Dioscorea species. The content of crude lipids in the multistage sampling technique in three consecutive tubers of Dioscorea species exhibited more crude lipid rainy seasons during August and January 2009 from content than the earlier reports in the tubers of D. alata the South Eastern Slopes of Western Ghats, (Udensi et al., 2008); D. oppositifolia, D, bulbifera, D. Virudhunagar district, Madurai district and pentaphylla, D. hispida (Rajyalakshmi and Geervani, Kanyakumari district, Tamil Nadu. 1994) and D. rotundata (Akissoe et al., 2001); D. calicola, D. daunea, D.wallichi, D. stemonoides and Moisture content was determined by drying the D. glabra (Maneenoon et al., 2008). The crude fibre samples in an oven at 80°C for 24hrs and was content in the presently investigated tubers of D. expressed on a percentage basis. The samples were esculenta, D. oppositifolia var oppositifolia, D. powdered in Willey mill 60 mesh sizes and stored in pentaphylla var pentaphylla, D.spicata and D. wallichi screw cap bottles at room temperature for further were found to be more than that in the earlier reports analysis. Nitrogen content was estimated by the micro- in D. bulbifera (Pramila et al., 1991); D. oppositifolia, kjeldhal method