Nutritional and anti-nutritional physicochemical composition of cocoyam accessions grown under upland conditions

Abstract

Cocoyam (Colocasia esculenta (L.) Schott) is commonly grown in wetlands, which are ecologically fragile ecosystems that should be conserved. The objective of this study, therefore, was to evaluate the effect of growing wetland adapted cocoyam in upland conditions on the nutritional and anti-nutritional properties of the edible parts of the crop. Four distinct accessions of Colocasia esculenta were collected from farmers in four agro ecological zones of southwestern Uganda. The accessions were planted under upland conditions as their counterparts in the wetland. The accessions were grown in a Randomized Complete Block Design (RCBD) with three replications at Mbarara Zonal Agricultural Research and Development Institute, Mbarara District, Uganda.Though there were no clear distinctions in nutritional composition of corms and leaves between upland and wetland habitats; there were highly significant differences in moisture, starch, total carbohydrate, sugars, proteins, and fibre in corms and leaves among the four accessions. On the other hand, there were significant differences in anti-nutritional (cyanide and oxalic acid) content of corms and leaves of C. esculenta accessions between upland and wetland conditions. The values for cyanide and oxalic acid obtained in C esculenta in this study were also significantly higher than WHO acceptable levels for human and other animals’ consumption. As such, though upland areas offer opportunities for increased production of the crop without affecting the nutritional status of the crop, methods of preparation that emphasize reduction of the anti-nutritional contents of the crop need meticulous attention in order to expand the to production boundary to upland conditions.