Evaluation of the Chemical Composition of Cameroonian Yam Germplasm

Abstract

The chemical composition of 98 culivars belonging to eight yam species extensively grown and consumed in Cameroon was evaluated. Due to the fact that statistical anaylsis showed no significant differences between the means obtained for the variables estimated for Dioscorea cayenensis and D. rotundata cultivars, these two yam species have been treated in this study as a single species termed D. cayensis/rotundata complex. On the basis of dry matter content, the yam species could be divided into three groups, low (23-25 g 100g −1, D. alata, D. dumetorum, and D. schimperiana), intermediate (28-30 g 100g −1, D. esculenta and D. bulbifera), and high (32-37 g 100g −1, D. cayensis/rotundata complex and D. liebrechtsiana). There was a great variability in protein levels among the yam species, which makes possible the selection of protein-rich cultivars. Mean fat levels were very low (0.1-0.9 g 100 g −1). Starch contents ranged from mean value of 70.4 to 72.9 g 100g −1, except for D. cayenensis/rotundata complex and D. Liebrechtsiana, which had levels higher than 80 g 100 g −1. D. dumetorum tubers had the highest levels of plant cell wall carbohydrates and almost all the minerals analyzed. Mulitvariate analysis has shown that some of the variables estimated and chosen in a stepwise manner could be used with a low probability error to differentiate among the cultivars within a yam species.