Riley, Cliff K.; Wheatley, Andrew O.; Hassan, Ishmael; Ahmad, Mohammed H.; Morrison, Errol Y. ; Asemota, Helen N.
Author Affiliation, Ana.
Department of Basic Medical Sciences
In Vitro Digestibility of Raw Starches Extracted from Five Yam (Dioscorea sp.) Grown in Jamaica
Date of Publication
Yams are important sources of carbohydrates in the diet of millions of people in the tropical and subtropical world, where 70-80% of the dry mass is starch. This study was designed to investigate the physiochemical characteristics of starches from different yam varieties and their influence on digestibility.Starches from five yam varieties grown in Jamaican were extracted. The physiochemical properties; crystallinity determined by X-ray crystallography, granular size and the amylose content were determined and their effects on starch digestibility assessed. Scanning electron microscopy, Crystallinity and amylose contents were determined by the method of Farhat et al (1990) and in vitro digestibility determined by method of Moorthy et al (1999). Statistical differences of starch variables were obtained by use of the studentís t test.X-ray diffractograms of Round leaf yellow yam (Dioscorea cayenensis), Sweet yam (Dioscorea alata), and Negro yam (Dioscorea rotundata) showed open hydrated hexagonal crystallites (type B). However, Bitter yam (Dioscorea dumentorum) had denser crystallites, with staggered monoclinic packing (type A), and Chinese yam (Dioscorea esculenta) the intermediate type crystallites (type C). (AU)....