INTERNATIONAL JOURNAL OF FOOD AND NUTRITION SCIENCE VOL NO1 JUNE 13 ISSN 1-3 (PRINT) ISSN 1-31 (ONLINE) http://www.researchpub.org/journal/ijfns/ijfns.html Technical Sheet of Some Wild Yam (Dioscorea) Starch A. D Sahoré* and N. G Amani Food Sciences and Technology Department, Nangui Abrogoua University, - B. P 1 Abidjan -, Côte d Ivoire Abstract-The morphological properties of starches, extracted from tuber of some wild yam species: Dioscorea praehensilis, Dioscorea hirtiflora. Dioscorea bulbifera (bulbil and tuber) Dioscorea multiflora, Dioscorea burkilliana, Dioscorea dumetorum and Dioscorea togoensis picked in the Ivory Coast forest zone, have been determined. The results showed a wide variety of starches from one species to another at the morphological level. The starches granules had different shapes: triangular, ellipsoidal triangular polyhedral ovo. The grain size varies from.3 µm to 9 µm. The distribution of starch granule sizes frequency depended on the species. It was great for Dioscorea burkilliana (11.µm to 9μm) and small for Dioscorea dumetorum (.3µm to.7µm) Keywords: wild, yam, species, starch, granule, size, morphological 1-INTRODUCTION The word yam was a generic name which indicated a set of plants of several species (more than ) of the kind Dioscorea restarted on all the continents. Only ten of these species were domesticated and gave of numerous cultivars [1] [] [3]. It was to say that the majority of the species of Dioscorea were in the wild state. Research projects concerning yams (Dioscorea) integrated little the wild forms which are left by little known plants [] [3]. The new data obtained in the investigation of physicochemical properties of these yams allowed a significant knowledge of these wild tubers and help promote their use in the artisanal or industrial, food and non-food The physicochemical properties of yam (Dioscorea) are known, at least for the main species as indicated by the work of Coursey []; Ketiku and Oyenuga [] Martin and Sadik [7] ; Delpeuch et al, []; Martin and Delpin, [1], and other.also, the interest to know those of the wild species of yam can be registered in this dynamic of research. Many researchers studied the physicochemical properties of the yams in particular the properties of the starches of yam which constituted with the flours of yam the principal processed products of the yam [ ] [ 11 ] [ 1 ] [ 13 ] [ 1 ]. The different uses of yam showed its scientific value [] and they justified the interest of the study of these species wild yam. This study also provided a source of information about the properties of starches that can be used for potential applications in industry. On the specific the species of wild yam Dioscorea praehensilis, Dioscorea hirtiflora, Dioscorea bulbifera (bulbil and tuber), Dioscorea burkilliana, Dioscorea togoensis, Dioscorea dumetorum and Dioscorea minutiflora commonly found in the forest in the Ivory Coast, are examined in relation to the morphology of their starches.. MATERIAL AND METHODS Vegetable material Tubers of wild yam species (Dioscorea praehensilis, Dioscorea hirtiflora, Dioscorea bulbifera, Dioscorea multiflora, Dioscorea burkilliana, Dioscorea dumetorum and Dioscorea togoensis) picked in the Ivory Coast forest zone Methods Starch extracted from tuber of wild yam (Dioscorea) species according to the method of Delpeuch et al [] (fig.1). The morphology of starch granule observed under a scanning electron Microscope (Cambridge Instrument Stereoscan 1 - England) The distribution of the mean diameter (average major axis + minor axis) Made on a total of granules (Rasper, 1971) [1] The shape and size of the granules observed in the lugol (I / KI. /.%) under a microscope (CETI - Belgium) with the 33
INTERNATIONAL JOURNAL OF FOOD AND NUTRITION SCIENCE VOL NO1 JUNE 13 ISSN 1-3 (PRINT) ISSN 1-31 (ONLINE) http://www.researchpub.org/journal/ijfns/ijfns.html objective.the granule size is determined by using an eyepiece scale. Yam tubers Weighing Peeling Washing Cutting 9.. 7.... 3.. 1...13.1..3..3.33.3...7..3.. Figure Distribution of D. praehensilis Starch granule size Average diameter of the granules 3 µm Mode of distribution (3 µm) Grinding Sieving (1 µm) successive washes NaCl% Successive washes Wet starch Supern atant FOTO 3: Tuber of D. minutiflora FOTO : Ellipsoidal granule of D. minutiflora Starch Baking ( C/ h) Grinding Dry starch 1 9 Figure 1: Extraction of yam tubers starch [] 7 3. RESULTS AND DISCUSSION 3 1 11. 1. 1.. 31. 3. 1. 3. 7. 1.. 1. 7. Figure 3: Distribution of D. minutiflora Starch granule size Average diameter of the granules µm Mode of distribution (3 µm) FOTO 1.Tuber of D. praehensilis FOTO : Ovo triangular granule of D. praehensilis Starch 3
Number of granule Number of granule INTERNATIONAL JOURNAL OF FOOD AND NUTRITION SCIENCE VOL NO1 JUNE 13 ISSN 1-3 (PRINT) ISSN 1-31 (ONLINE) http://www.researchpub.org/journal/ijfns/ijfns.html 1 1 1 1 1 11. 1. 1. 1... 31. 3. 37. FOTO : Tuber of D. burkilliana FOTO : Ovo triangular granule of D. burkilliana Starch Figure : Distribution of D. hirtiflora starch granule size Average diameter of the granules µm Mode of distribution (1, µm) 1 9 7 3 1 1 1 19 7 3 3 3 9 3 7 9 9 Figure : Distribution of D. burkilliana Starch granule size Average diameter of the granules µm Mode of distribution ( µm) FOTO 9: tuber of D. dumetorum 3 3 1 1 FOTO 1: Polyhedric granule of D. hirtiflora starch. 1. 1.7 3.3...7 granule size µm Figure : Distribution of D. dumetorum starch granule size Average diameter of the granules µm Mode of distribution (1, µm) FOTO 7: tuber of D. hirtiflora FOTO : Ovo triangular granule of D. hirtiflora starch 3
Number ol granules number of granule INTERNATIONAL JOURNAL OF FOOD AND NUTRITION SCIENCE VOL NO1 JUNE 13 ISSN 1-3 (PRINT) ISSN 1-31 (ONLINE) http://www.researchpub.org/journal/ijfns/ijfns.html 1 1 FOTO 11: tuber of D. togoensis FOTO 1: Ovo triangular granule of D. togoensis starch.1.1.1...3.33.3.37..3... granule size µm) Figure : Distribution of D. togoensis starch granule size Average diameter of the granules 31 µm Mode of distribution (3 µm) 1 1 1 1 Bulbil 13 17 3 7 3 33 37 3 7 3 7 3 Figure 7: Distribution of D. togoensis starch granule size Average diameter of the granules 3 µm Mode of distribution ( µm) Foto: 1 Tuber of D. bulbifera Foto 1: Ovo triangular granule of D. bulbifera Bulbi 1 1 Tubers 13.1. 3.. 3 33 3 37 3. Foto: 13 Tuber of D. bulbifera Foto 1: Ovo triangular granule of D. bulbifera tuber Figure 7: Distribution of D. togoensis starch granule size Average diameter of the granules 31 µm Mode of distribution (3, µm) 3
INTERNATIONAL JOURNAL OF FOOD AND NUTRITION SCIENCE VOL NO1 JUNE 13 ISSN 1-3 (PRINT) ISSN 1-31 (ONLINE) http://www.researchpub.org/journal/ijfns/ijfns.html The examination of the forms allowed us to observe four groups of starch (Triangular, Ovo triangular, Polyhedral and Ellipsoidal). These different groups have the starch grain shapes comparable to those grains of starch extracts from the yam cultivated Dioscorea alata, Dioscorea cayenensis and Dioscorea rotundata [] Groups of the starch have a distribution of grain size, uniform and asymmetric, except, the starch extracted from Dioscorea dumetorum whose grain size distribution is symmetric and centered on 3.3 microns The distribution range of the starch groups studied grain size extends from. microns (Dioscorea dumetorum) to 9 microns (Dioscorea burkilliana). It is wider than that of the cultivated yam starch which extends from. to microns [1]. Compared to the modes of the distribution for each variety of starch grains we can deduce that the different groups of starch, surveyed throughout large grains except the sample of Dioscorea dumetorum.. CONCLUSION The granules of starch extracted from the wild yam species were very variable and characteristic forms for each type of starch. The different types of starch are studied throughout the large grains except those of starch from Dioscorea dumetorum composed of small grains. The distribution range of the grain size is large. REFERENCES [1] Knuth R., Dioscoreaceae In Engler. Das Pflanzenreich, 19, 7 (IV-3)1-37 [] L. Degras. L igname, plante à tubercule tropical. Technique agricoles et production tropicale. Maisonneuve et Larose. Paris.19, p. [3] P. Hamon, Dumont, J. Zoundjihekpon, B. Tio- Touré, S. Hamon. Les ignames sauvages d Afrique de l Ouest. Caractères morphologiques. ORSTOM Paris. 199. [] S. Trèche. Potentialités nutritionnelles des ignames (Dioscorea spp) cultivées au Cameroun. Eds ORSTOM. Collection études et thèses. Paris.199, [] D. G Coursey. Yam, an account of the Nature, Origin, Cultivation and utilisation of the useful members of the Dioscoreacea Tropical agriculture series, tropical Products institute... London, U.K, 197, 3 p [] A. O Ketiku, V. A Oyenuga. Changes in the Carbohydrate constituents of yam tuber (Dioscorea rotunda Poir) during growth. J. Sci.ed.Agric.1973. : 3 [7] F.W Martin, S. Sadik S., Tropical yams and their Potential Part.. Dioscorea.1. 1977. [] F. Delpeuch, J.C Favier, R. Charbonnière.. Caractéristiques des amidons des plantes. Ann. Techno. Agric 197.7, ().9- [9] F.W Martin, H. Delpin. New superior varieties of Dioscorea alata: the Asian greater yam. J. Agric. Univ. 197. P. R. ; 7 [1] L.Emiola, L. Delarosa. Characteristics of Dioscorea Rotundata of polyphenolisidase Journal of Applied Biochemistry.19..; 1 11 [11] A. Kamenan, L. R Benchat, M.S Schinnan, E. K Heaton,. Composition and physicochemical Properties of Yam (Dioscorea species): Flour Prepared Using Different Processes Journal of Food Processing and preservation.197, 11:99 3 [1] T. Muzac-Tucker, H. N Asemota, M. H Ahmad 1993 Biochemical Composition and Storage of Jamaican Yams (Dioscorea sp) Journal of Sci. of Food and Agric. : 19 [13] I. A Farh197at, O.Tunde, J. N Roger. Characterisation of Starches from West African Yams. J. Sci. Food Agric, 1999, 79, 1 11 [1] Rasper V. Investigation on starches from major Starch crops grown in Ghana. III. Particles size and Particles size distribution. Journal of the Science of Food and Agriculture, 1971., 7- [1] Amani N. G. Propriétés physico-chimiques et Moléculaires des amidons d-ignames (Dioscorea, spp) cultivées en Côte d Ivoire. Relation avec la stabilitédes gels aux Traitements Technologiques. Thèse de Doctorat es science. Univ Abobo-Adjamé Côte d Ivoire, 1 p 37