Comparison of Storage Stability of three Yam Species in a Humid Environment

Abstract

The chemical composition of three yam species (Dioscorea rotundata Poir, D. esculenta (Lour) Burk and D. bulbiferaL.) was estimated as a measure of storage stability and susceptibility/tolerance to Penicillium oxilicum. Free fatty acid (FFA) and peroxide value (PV) were highest in Dioscorea bulbiferafollowed by D. rotundata and least in D. esculenta indicating a better storage stability in D. esculenta. The biochemical functions of the tubers, estimated as the quantity of Krebs Cycle acids, indicated the highest quantity in D. bulbiferafollowed by D. rotundata and least in D. esculenta. The biochemical functions were lower 3 months after harvesting indicating the initiation of tuber dormancy and higher 6 months after harvesting which coincided with the initiation of tuber sprouting, thus, showing the increased metabolic activities during sprouting. However, the quantity of ascorbic acid was highest in D. esculenta followed by D. rotundataand least in D. bulbifera. The extent of tuber rot by Penicillium oxilicum confirmed that D. esculentawas the most tolerant of the species and therefore most stable in storage, followed by D. rotundataand least is D. bulbifera. The differential amounts of the chemicals could be an indicator for screening yam species for tolerance/susceptibility to rot organisms and thus for estimating their storage stability.


Keywords: Yam species, rot organism, storage stability and yam storage


[IJARD Vol.3 2002: 127-130]